1
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Nascimento MA, Biagiotti S, Herranz-Pérez V, Santiago S, Bueno R, Ye CJ, Abel TJ, Zhang Z, Rubio-Moll JS, Kriegstein AR, Yang Z, Garcia-Verdugo JM, Huang EJ, Alvarez-Buylla A, Sorrells SF. Protracted neuronal recruitment in the temporal lobes of young children. Nature 2024; 626:1056-1065. [PMID: 38122823 PMCID: PMC10901738 DOI: 10.1038/s41586-023-06981-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 12/07/2023] [Indexed: 12/23/2023]
Abstract
The temporal lobe of the human brain contains the entorhinal cortex (EC). This region of the brain is a highly interconnected integrative hub for sensory and spatial information; it also has a key role in episodic memory formation and is the main source of cortical hippocampal inputs1-4. The human EC continues to develop during childhood5, but neurogenesis and neuronal migration to the EC are widely considered to be complete by birth. Here we show that the human temporal lobe contains many young neurons migrating into the postnatal EC and adjacent regions, with a large tangential stream persisting until the age of around one year and radial dispersal continuing until around two to three years of age. By contrast, we found no equivalent postnatal migration in rhesus macaques (Macaca mulatta). Immunostaining and single-nucleus RNA sequencing of ganglionic eminence germinal zones, the EC stream and the postnatal EC revealed that most migrating cells in the EC stream are derived from the caudal ganglionic eminence and become LAMP5+RELN+ inhibitory interneurons. These late-arriving interneurons could continue to shape the processing of sensory and spatial information well into postnatal life, when children are actively interacting with their environment. The EC is one of the first regions of the brain to be affected in Alzheimer's disease, and previous work has linked cognitive decline to the loss of LAMP5+RELN+ cells6,7. Our investigation reveals that many of these cells arrive in the EC through a major postnatal migratory stream in early childhood.
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Affiliation(s)
- Marcos Assis Nascimento
- Department of Neurological Surgery, University of California, San Francisco, CA, USA.
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, USA.
| | - Sean Biagiotti
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Vicente Herranz-Pérez
- Laboratory of Comparative Neurobiology, Institute Cavanilles, University of Valencia, CIBERNED, Valencia, Spain
- Department of Cell Biology, Functional Biology and Physical Anthropology, University of Valencia, Burjassot, Spain
| | - Samara Santiago
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Neuroscience Graduate Training Program, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition at the University of Pittsburgh, Pittsburgh, PA, USA
| | - Raymund Bueno
- Institute of Human Genetics, University of California, San Francisco, CA, USA
- Division of Rheumatology, Department of Medicine, University of California, San Francisco, CA, USA
| | - Chun J Ye
- Institute of Human Genetics, University of California, San Francisco, CA, USA
- Division of Rheumatology, Department of Medicine, University of California, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA
- Institute of Computational Health Sciences, University of California, San Francisco, CA, USA
- Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Taylor J Abel
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zhuangzhi Zhang
- State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Juan S Rubio-Moll
- Servicio de Obstetricia, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | - Arnold R Kriegstein
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Zhengang Yang
- State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jose Manuel Garcia-Verdugo
- Laboratory of Comparative Neurobiology, Institute Cavanilles, University of Valencia, CIBERNED, Valencia, Spain
| | - Eric J Huang
- Department of Pathology, University of California, San Francisco, CA, USA
| | - Arturo Alvarez-Buylla
- Department of Neurological Surgery, University of California, San Francisco, CA, USA.
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, USA.
| | - Shawn F Sorrells
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA.
- Center for Neuroscience Graduate Training Program, University of Pittsburgh, Pittsburgh, PA, USA.
- Center for the Neural Basis of Cognition at the University of Pittsburgh, Pittsburgh, PA, USA.
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2
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Gonzalo Cogno S, Obenhaus HA, Lautrup A, Jacobsen RI, Clopath C, Andersson SO, Donato F, Moser MB, Moser EI. Minute-scale oscillatory sequences in medial entorhinal cortex. Nature 2024; 625:338-344. [PMID: 38123682 PMCID: PMC10781645 DOI: 10.1038/s41586-023-06864-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 11/10/2023] [Indexed: 12/23/2023]
Abstract
The medial entorhinal cortex (MEC) hosts many of the brain's circuit elements for spatial navigation and episodic memory, operations that require neural activity to be organized across long durations of experience1. Whereas location is known to be encoded by spatially tuned cell types in this brain region2,3, little is known about how the activity of entorhinal cells is tied together over time at behaviourally relevant time scales, in the second-to-minute regime. Here we show that MEC neuronal activity has the capacity to be organized into ultraslow oscillations, with periods ranging from tens of seconds to minutes. During these oscillations, the activity is further organized into periodic sequences. Oscillatory sequences manifested while mice ran at free pace on a rotating wheel in darkness, with no change in location or running direction and no scheduled rewards. The sequences involved nearly the entire cell population, and transcended epochs of immobility. Similar sequences were not observed in neighbouring parasubiculum or in visual cortex. Ultraslow oscillatory sequences in MEC may have the potential to couple neurons and circuits across extended time scales and serve as a template for new sequence formation during navigation and episodic memory formation.
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Affiliation(s)
- Soledad Gonzalo Cogno
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Fred Kavli Building, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Horst A Obenhaus
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Fred Kavli Building, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ane Lautrup
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Fred Kavli Building, Norwegian University of Science and Technology, Trondheim, Norway
| | - R Irene Jacobsen
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Fred Kavli Building, Norwegian University of Science and Technology, Trondheim, Norway
| | - Claudia Clopath
- Department of Bioengineering, Imperial College London, London, UK
| | - Sebastian O Andersson
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Fred Kavli Building, Norwegian University of Science and Technology, Trondheim, Norway
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - Flavio Donato
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Fred Kavli Building, Norwegian University of Science and Technology, Trondheim, Norway
- Biozentrum Universität Basel, Basel, Switzerland
| | - May-Britt Moser
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Fred Kavli Building, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Edvard I Moser
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Fred Kavli Building, Norwegian University of Science and Technology, Trondheim, Norway.
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3
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Yadav N, Noble C, Niemeyer JE, Terceros A, Victor J, Liston C, Rajasethupathy P. Prefrontal feature representations drive memory recall. Nature 2022; 608:153-160. [PMID: 35831504 PMCID: PMC9577479 DOI: 10.1038/s41586-022-04936-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 06/06/2022] [Indexed: 02/03/2023]
Abstract
Memory formation involves binding of contextual features into a unitary representation1-4, whereas memory recall can occur using partial combinations of these contextual features. The neural basis underlying the relationship between a contextual memory and its constituent features is not well understood; in particular, where features are represented in the brain and how they drive recall. Here, to gain insight into this question, we developed a behavioural task in which mice use features to recall an associated contextual memory. We performed longitudinal imaging in hippocampus as mice performed this task and identified robust representations of global context but not of individual features. To identify putative brain regions that provide feature inputs to hippocampus, we inhibited cortical afferents while imaging hippocampus during behaviour. We found that whereas inhibition of entorhinal cortex led to broad silencing of hippocampus, inhibition of prefrontal anterior cingulate led to a highly specific silencing of context neurons and deficits in feature-based recall. We next developed a preparation for simultaneous imaging of anterior cingulate and hippocampus during behaviour, which revealed robust population-level representation of features in anterior cingulate, that lag hippocampus context representations during training but dynamically reorganize to lead and target recruitment of context ensembles in hippocampus during recall. Together, we provide the first mechanistic insights into where contextual features are represented in the brain, how they emerge, and how they access long-range episodic representations to drive memory recall.
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Affiliation(s)
- Nakul Yadav
- Laboratory of Neural Dynamics and Cognition, The Rockefeller University, New York, NY, USA
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Chelsea Noble
- Laboratory of Neural Dynamics and Cognition, The Rockefeller University, New York, NY, USA
| | - James E Niemeyer
- Laboratory of Neural Dynamics and Cognition, The Rockefeller University, New York, NY, USA
- Department of Neurological Surgery, Weill Cornell Medicine, New York, NY, USA
| | - Andrea Terceros
- Laboratory of Neural Dynamics and Cognition, The Rockefeller University, New York, NY, USA
| | - Jonathan Victor
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Conor Liston
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
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Perez-Rando M, Guirado R, Tellez-Merlo G, Carceller H, Nacher J. Estradiol Regulates Polysialylated Form of the Neural Cell Adhesion Molecule Expression and Connectivity of O-LM Interneurons in the Hippocampus of Adult Female Mice. Neuroendocrinology 2022; 112:51-67. [PMID: 33550289 DOI: 10.1159/000515052] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 02/04/2021] [Indexed: 11/19/2022]
Abstract
The estrous cycle is caused by the changing concentration of ovarian hormones, particularly 17β-estradiol, a hormone whose effect on excitatory circuits has been extensively reported. However, fewer studies have tried to elucidate how this cycle, or this hormone, affects the plasticity of inhibitory networks and the structure of interneurons. Among these cells, somatostatin-expressing O-LM neurons of the hippocampus are especially interesting. They have a role in the modulation of theta oscillations, and they receive direct input from the entorhinal cortex, which place them in the center of hippocampal function. In this study, we report that the expression of polysialylated form of the neural cell adhesion molecule (PSA-NCAM) in the hippocampus, a molecule involved in the plasticity of somatostatin-expressing interneurons in the adult brain, fluctuated through the different stages of the estrous cycle. Likewise, these stages and the expression of PSA-NCAM affected the density of dendritic spines of O-LM cells. We also describe that 17β-estradiol replacement of adult ovariectomized female mice caused an increase in the perisomatic inhibitory puncta in O-LM interneurons as well as an increase in their axonal bouton density. Interestingly, this treatment also induced a decrease in their dendritic spine density, specifically in O-LM interneurons lacking PSA-NCAM expression. Finally, using an ex vivo real-time assay with entorhinal-hippocampal organotypic cultures, we show that this hormone decreased the dynamics in spinogenesis, altogether highlighting the modulatory effect that 17β-estradiol has on inhibitory circuits.
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Affiliation(s)
- Marta Perez-Rando
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
- Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
| | - Ramon Guirado
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
- Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
- Dirección General de Universidades, Gobierno de Aragón, Zaragoza, Spain
| | - Guillermina Tellez-Merlo
- Lab. Neuropsiquiatría, Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Hector Carceller
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
| | - Juan Nacher
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
- Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
- CIBERSAM: Spanish National Network for Research in Mental Health, Valencia, Spain
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5
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Palacios-Filardo J, Udakis M, Brown GA, Tehan BG, Congreve MS, Nathan PJ, Brown AJH, Mellor JR. Acetylcholine prioritises direct synaptic inputs from entorhinal cortex to CA1 by differential modulation of feedforward inhibitory circuits. Nat Commun 2021; 12:5475. [PMID: 34531380 PMCID: PMC8445995 DOI: 10.1038/s41467-021-25280-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 07/21/2021] [Indexed: 02/08/2023] Open
Abstract
Acetylcholine release in the hippocampus plays a central role in the formation of new memory representations. An influential but largely untested theory proposes that memory formation requires acetylcholine to enhance responses in CA1 to new sensory information from entorhinal cortex whilst depressing inputs from previously encoded representations in CA3. Here, we show that excitatory inputs from entorhinal cortex and CA3 are depressed equally by synaptic release of acetylcholine in CA1. However, feedforward inhibition from entorhinal cortex exhibits greater depression than CA3 resulting in a selective enhancement of excitatory-inhibitory balance and CA1 activation by entorhinal inputs. Entorhinal and CA3 pathways engage different feedforward interneuron subpopulations and cholinergic modulation of presynaptic function is mediated differentially by muscarinic M3 and M4 receptors, respectively. Thus, our data support a role and mechanisms for acetylcholine to prioritise novel information inputs to CA1 during memory formation.
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Affiliation(s)
- Jon Palacios-Filardo
- Center for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, UK
| | - Matt Udakis
- Center for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, UK
| | - Giles A Brown
- Sosei Heptares, Steinmetz Building, Granta Park, Great Abingdon, Cambridge, UK
- OMass Therapeutics Ltd, The Schrödinger Building, Oxford, UK
| | - Benjamin G Tehan
- Sosei Heptares, Steinmetz Building, Granta Park, Great Abingdon, Cambridge, UK
- OMass Therapeutics Ltd, The Schrödinger Building, Oxford, UK
| | - Miles S Congreve
- Sosei Heptares, Steinmetz Building, Granta Park, Great Abingdon, Cambridge, UK
| | - Pradeep J Nathan
- Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Alastair J H Brown
- Sosei Heptares, Steinmetz Building, Granta Park, Great Abingdon, Cambridge, UK
| | - Jack R Mellor
- Center for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, UK.
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Olajide OJ, Chapman CA. Amyloid-β (1-42) peptide induces rapid NMDA receptor-dependent alterations at glutamatergic synapses in the entorhinal cortex. Neurobiol Aging 2021; 105:296-309. [PMID: 34144329 DOI: 10.1016/j.neurobiolaging.2021.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/26/2021] [Accepted: 05/11/2021] [Indexed: 12/29/2022]
Abstract
The hippocampus and entorhinal cortex (EC) accumulate amyloid beta peptides (Aβ) that promote neuropathology in Alzheimer's disease, but the early effects of Aβ on excitatory synaptic transmission in the EC have not been well characterized. To assess the acute effects of Aβ1-42 on glutamatergic synapses, acute brain slices from wildtype rats were exposed to Aβ1-42 or control solution for 3 hours, and tissue was analyzed using protein immunoblotting and quantitative PCR. Presynaptically, Aβ1-42 induced marked reductions in synaptophysin, synapsin-2a mRNA, and mGluR3 mRNA, and increased both VGluT2 protein and Ca2+-activated channel KCa2.2 mRNA levels. Postsynaptically, Aβ1-42 reduced PSD95 and GluN2B protein, and also downregulated GluN2B and GluN2A mRNA, without affecting scaffolding elements SAP97 and PICK1. mGluR5 mRNA was strongly increased, while mGluR1 mRNA was unaffected. Blocking either GluN2A- or GluN2B-containing NMDA receptors did not significantly prevent synaptic changes induced by Aβ1-42, but combined blockade did prevent synaptic alterations. These findings demonstrate that Aβ1-42 rapidly disrupts glutamatergic transmission in the EC through mechanisms involving concurrent activation of GluN2A- and GluN2B-containing NMDA receptors.
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Affiliation(s)
- Olayemi Joseph Olajide
- Division of Neurobiology, Department of Anatomy, University of Ilorin, Ilorin, Nigeria; Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada
| | - Clifton Andrew Chapman
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada.
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7
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Meier AM, Wang Q, Ji W, Ganachaud J, Burkhalter A. Modular Network between Postrhinal Visual Cortex, Amygdala, and Entorhinal Cortex. J Neurosci 2021; 41:4809-4825. [PMID: 33849948 PMCID: PMC8260166 DOI: 10.1523/jneurosci.2185-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 11/21/2022] Open
Abstract
The postrhinal area (POR) is a known center for integrating spatial with nonspatial visual information and a possible hub for influencing landmark navigation by affective input from the amygdala. This may involve specific circuits within muscarinic acetylcholine receptor 2 (M2)-positive (M2+) or M2- modules of POR that associate inputs from the thalamus, cortex, and amygdala, and send outputs to the entorhinal cortex. Using anterograde and retrograde labeling with conventional and viral tracers in male and female mice, we found that all higher visual areas of the ventral cortical stream project to the amygdala, while such inputs are absent from primary visual cortex and dorsal stream areas. Unexpectedly for the presumed salt-and-pepper organization of mouse extrastriate cortex, tracing results show that inputs from the dorsal lateral geniculate nucleus and lateral posterior nucleus were spatially clustered in layer 1 (L1) and overlapped with M2+ patches of POR. In contrast, input from the amygdala to L1 of POR terminated in M2- interpatches. Importantly, the amygdalocortical input to M2- interpatches in L1 overlapped preferentially with spatially clustered apical dendrites of POR neurons projecting to amygdala and entorhinal area lateral, medial (ENTm). The results suggest that subnetworks in POR, used to build spatial maps for navigation, do not receive direct thalamocortical M2+ patch-targeting inputs. Instead, they involve local networks of M2- interpatches, which are influenced by affective information from the amygdala and project to ENTm, whose cells respond to visual landmark cues for navigation.SIGNIFICANCE STATEMENT A central purpose of visual object recognition is identifying the salience of objects and approaching or avoiding them. However, it is not currently known how the visual cortex integrates the multiple streams of information, including affective and navigational cues, which are required to accomplish this task. We find that in a higher visual area, the postrhinal cortex, the cortical sheet is divided into interdigitating modules receiving distinct inputs from visual and emotion-related sources. One of these modules is preferentially connected with the amygdala and provides outputs to entorhinal cortex, constituting a processing stream that may assign emotional salience to objects and landmarks for the guidance of goal-directed navigation.
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Affiliation(s)
- Andrew M Meier
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Quanxin Wang
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Weiqing Ji
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Jehan Ganachaud
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Andreas Burkhalter
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
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Bondi H, Bortolotto V, Canonico PL, Grilli M. Complex and regional-specific changes in the morphological complexity of GFAP + astrocytes in middle-aged mice. Neurobiol Aging 2021; 100:59-71. [PMID: 33493951 DOI: 10.1016/j.neurobiolaging.2020.12.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/14/2020] [Accepted: 12/19/2020] [Indexed: 02/06/2023]
Abstract
During aging, alterations in astrocyte phenotype occur in areas associated with age-related cognitive decline, including hippocampus. Previous work reported subregion-specific changes in surface, volume, and soma size of hippocampal astrocytes during physiological aging. Herein we extensively analyzed, by morphometric analysis, fine morphological features of GFAP+ astrocytes in young (6-month-old) and middle-aged (14-month-old) male mice. We observed remarkable heterogeneity in the astrocytic response to aging in distinct subfields and along the dorsoventral axis of hippocampus and in entorhinal cortex. In middle-aged mice dorsal granule cell and molecular layers, but not hilus, astrocytes underwent remarkable increase in their morphological complexity. These changes were absent in ventral Dentate Gyrus (DG). In addition, in entorhinal cortex, the major input to dorsal DG, astrocytes underwent remarkable atrophic changes in middle-aged mice. Since dorsal DG, and not ventral DG, is involved in cognitive functions, these findings appear worth of further evaluation. Our findings also suggest an additional level of complexity in the structural changes associated with brain aging.
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Affiliation(s)
- Heather Bondi
- Laboratory of Neuroplasticity, Department of Pharmaceutical Sciences, University of Piemonte Orientale, Novara, Italy; Department of Pharmaceutical Sciences, University of Piemonte Orientale, Novara, Italy
| | - Valeria Bortolotto
- Laboratory of Neuroplasticity, Department of Pharmaceutical Sciences, University of Piemonte Orientale, Novara, Italy; Department of Pharmaceutical Sciences, University of Piemonte Orientale, Novara, Italy
| | - Pier Luigi Canonico
- Department of Pharmaceutical Sciences, University of Piemonte Orientale, Novara, Italy
| | - Mariagrazia Grilli
- Laboratory of Neuroplasticity, Department of Pharmaceutical Sciences, University of Piemonte Orientale, Novara, Italy; Department of Pharmaceutical Sciences, University of Piemonte Orientale, Novara, Italy.
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9
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Schlesiger MI, Ruff T, MacLaren DAA, Barriuso-Ortega I, Saidov KM, Yen TY, Monyer H. Two septal-entorhinal GABAergic projections differentially control coding properties of spatially tuned neurons in the medial entorhinal cortex. Cell Rep 2021; 34:108801. [PMID: 33657367 DOI: 10.1016/j.celrep.2021.108801] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 12/23/2020] [Accepted: 02/05/2021] [Indexed: 12/20/2022] Open
Abstract
Septal parvalbumin-expressing (PV+) and calbindin-expressing (CB+) projections inhibit low-threshold and fast-spiking interneurons, respectively, in the medial entorhinal cortex (MEC). We investigate how the two inputs control neuronal activity in the MEC in freely moving mice. Stimulation of PV+ and CB+ terminals causes disinhibition of spatially tuned MEC neurons, but exerts differential effects on temporal coding and burst firing. Thus, recruitment of PV+ projections disrupts theta-rhythmic firing of MEC neurons, while stimulation of CB+ projections increases burst firing of grid cells and enhances phase precession in a cell-type-specific manner. Inactivation of septal PV+ or CB+ neurons differentially affects context, reference, and working memory. Together, our results reveal how specific connectivity of septal GABAergic projections with MEC interneurons translates into differential modulation of MEC neuronal coding.
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Affiliation(s)
- Magdalene Isabell Schlesiger
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Tobias Ruff
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Duncan Archibald Allan MacLaren
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Isabel Barriuso-Ortega
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Khalid Magomedovich Saidov
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Ting-Yun Yen
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Hannah Monyer
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
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10
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Calderazzo SM, Busch SE, Moore TL, Rosene DL, Medalla M. Distribution and overlap of entorhinal, premotor, and amygdalar connections in the monkey anterior cingulate cortex. J Comp Neurol 2021; 529:885-904. [PMID: 32677044 PMCID: PMC8214921 DOI: 10.1002/cne.24986] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 06/17/2020] [Accepted: 07/11/2020] [Indexed: 12/22/2022]
Abstract
The anterior cingulate cortex (ACC) is important for decision-making as it integrates motor plans with affective and contextual limbic information. Disruptions in these networks have been observed in depression, bipolar disorder, and post-traumatic stress disorder. Yet, overlap of limbic and motor connections within subdivisions of the ACC is not well understood. Hence, we administered a combination of retrograde and anterograde tracers into structures important for contextual memories (entorhinal cortex), affective processing (amygdala), and motor planning (dorsal premotor cortex) to assess overlap of labeled projection neurons from (outputs) and axon terminals to (inputs) the ACC of adult rhesus monkeys (Macaca mulatta). Our data show that entorhinal and dorsal premotor cortical (dPMC) connections are segregated across ventral (A25, A24a) and dorsal (A24b,c) subregions of the ACC, while amygdalar connections are more evenly distributed across subregions. Among all areas, the rostral ACC (A32) had the lowest relative density of connections with all three regions. In the ventral ACC, entorhinal and amygdalar connections strongly overlap across all layers, especially in A25. In the dorsal ACC, outputs to dPMC and the amygdala strongly overlap in deep layers. However, dPMC input to the dorsal ACC was densest in deep layers, while amygdalar inputs predominantly localized in upper layers. These connection patterns are consistent with diverse roles of the dorsal ACC in motor evaluation and the ventral ACC in affective and contextual memory. Further, distinct laminar circuits suggest unique interactions within specific ACC compartments that are likely important for the temporal integration of motor and limbic information during flexible goal-directed behavior.
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Affiliation(s)
- Samantha M. Calderazzo
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts
| | - Silas E. Busch
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts
- Department of Neurobiology, University of Chicago, Chicago, Illinois
| | - Tara L. Moore
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts
| | - Douglas L. Rosene
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts
| | - Maria Medalla
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts
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11
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Mallory CS, Hardcastle K, Campbell MG, Attinger A, Low IIC, Raymond JL, Giocomo LM. Mouse entorhinal cortex encodes a diverse repertoire of self-motion signals. Nat Commun 2021; 12:671. [PMID: 33510164 PMCID: PMC7844029 DOI: 10.1038/s41467-021-20936-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 12/31/2020] [Indexed: 01/30/2023] Open
Abstract
Neural circuits generate representations of the external world from multiple information streams. The navigation system provides an exceptional lens through which we may gain insights about how such computations are implemented. Neural circuits in the medial temporal lobe construct a map-like representation of space that supports navigation. This computation integrates multiple sensory cues, and, in addition, is thought to require cues related to the individual's movement through the environment. Here, we identify multiple self-motion signals, related to the position and velocity of the head and eyes, encoded by neurons in a key node of the navigation circuitry of mice, the medial entorhinal cortex (MEC). The representation of these signals is highly integrated with other cues in individual neurons. Such information could be used to compute the allocentric location of landmarks from visual cues and to generate internal representations of space.
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Affiliation(s)
- Caitlin S Mallory
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Kiah Hardcastle
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Malcolm G Campbell
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Alexander Attinger
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Isabel I C Low
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Jennifer L Raymond
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Lisa M Giocomo
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, USA.
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12
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Christensen AC, Lensjø KK, Lepperød ME, Dragly SA, Sutterud H, Blackstad JS, Fyhn M, Hafting T. Perineuronal nets stabilize the grid cell network. Nat Commun 2021; 12:253. [PMID: 33431847 PMCID: PMC7801665 DOI: 10.1038/s41467-020-20241-w] [Citation(s) in RCA: 238] [Impact Index Per Article: 79.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 11/16/2020] [Indexed: 11/29/2022] Open
Abstract
Grid cells are part of a widespread network which supports navigation and spatial memory. Stable grid patterns appear late in development, in concert with extracellular matrix aggregates termed perineuronal nets (PNNs) that condense around inhibitory neurons. It has been suggested that PNNs stabilize synaptic connections and long-term memories, but their role in the grid cell network remains elusive. We show that removal of PNNs leads to lower inhibitory spiking activity, and reduces grid cells' ability to create stable representations of a novel environment. Furthermore, in animals with disrupted PNNs, exposure to a novel arena corrupted the spatiotemporal relationships within grid cell modules, and the stored representations of a familiar arena. Finally, we show that PNN removal in entorhinal cortex distorted spatial representations in downstream hippocampal neurons. Together this work suggests that PNNs provide a key stabilizing element for the grid cell network.
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Affiliation(s)
- Ane Charlotte Christensen
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
| | - Kristian Kinden Lensjø
- Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
| | - Mikkel Elle Lepperød
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
| | - Svenn-Arne Dragly
- Center for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
- Department of Physics, University of Oslo, Oslo, Norway
| | - Halvard Sutterud
- Center for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
- Department of Physics, University of Oslo, Oslo, Norway
| | - Jan Sigurd Blackstad
- Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
| | - Marianne Fyhn
- Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
| | - Torkel Hafting
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
- Center for Integrative Neuroplasticity, University of Oslo, Oslo, Norway.
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13
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Ridler T, Witton J, Phillips KG, Randall AD, Brown JT. Impaired speed encoding and grid cell periodicity in a mouse model of tauopathy. eLife 2020; 9:59045. [PMID: 33242304 PMCID: PMC7690954 DOI: 10.7554/elife.59045] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/16/2020] [Indexed: 12/13/2022] Open
Abstract
Dementia is associated with severe spatial memory deficits which arise from dysfunction in hippocampal and parahippocampal circuits. For spatially sensitive neurons, such as grid cells, to faithfully represent the environment these circuits require precise encoding of direction and velocity information. Here, we have probed the firing rate coding properties of neurons in medial entorhinal cortex (MEC) in a mouse model of tauopathy. We find that grid cell firing patterns are largely absent in rTg4510 mice, while head-direction tuning remains largely intact. Conversely, neural representation of running speed information was significantly disturbed, with smaller proportions of MEC cells having firing rates correlated with locomotion in rTg4510 mice. Additionally, the power of local field potential oscillations in the theta and gamma frequency bands, which in wild-type mice are tightly linked to running speed, was invariant in rTg4510 mice during locomotion. These deficits in locomotor speed encoding likely severely impact path integration systems in dementia.
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Affiliation(s)
- Thomas Ridler
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Hatherly LaboratoriesExeterUnited Kingdom
| | - Jonathan Witton
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Hatherly LaboratoriesExeterUnited Kingdom
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University WalkBristolUnited Kingdom
| | - Keith G Phillips
- Lilly United Kingdom Erl Wood Manor WindleshamSurreyUnited Kingdom
| | - Andrew D Randall
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Hatherly LaboratoriesExeterUnited Kingdom
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University WalkBristolUnited Kingdom
| | - Jonathan T Brown
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Hatherly LaboratoriesExeterUnited Kingdom
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14
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Gerlei K, Passlack J, Hawes I, Vandrey B, Stevens H, Papastathopoulos I, Nolan MF. Grid cells are modulated by local head direction. Nat Commun 2020; 11:4228. [PMID: 32839445 PMCID: PMC7445272 DOI: 10.1038/s41467-020-17500-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 07/02/2020] [Indexed: 01/11/2023] Open
Abstract
Grid and head direction codes represent cognitive spaces for navigation and memory. Pure grid cells generate grid codes that have been assumed to be independent of head direction, whereas conjunctive cells generate grid representations that are tuned to a single head direction. Here, we demonstrate that pure grid cells also encode head direction, but through distinct mechanisms. We show that individual firing fields of pure grid cells are tuned to multiple head directions, with the preferred sets of directions differing between fields. This local directional modulation is not predicted by previous continuous attractor or oscillatory interference models of grid firing but is accounted for by models in which pure grid cells integrate inputs from co-aligned conjunctive cells with firing rates that differ between their fields. We suggest that local directional signals from grid cells may contribute to downstream computations by decorrelating different points of view from the same location.
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Affiliation(s)
- Klara Gerlei
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Jessica Passlack
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Ian Hawes
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Brianna Vandrey
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Holly Stevens
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Ioannis Papastathopoulos
- School of Mathematics, Maxwell Institute and Centre for Statistics, University of Edinburgh, Edinburgh, EH9 3FD, UK
- The Alan Turing Institute, 96 Euston Road, London, NW1 2DB, UK
| | - Matthew F Nolan
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, UK.
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15
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Ekstrom AD, Harootonian SK, Huffman DJ. Grid coding, spatial representation, and navigation: Should we assume an isomorphism? Hippocampus 2020; 30:422-432. [PMID: 31742364 PMCID: PMC7409510 DOI: 10.1002/hipo.23175] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/21/2019] [Accepted: 10/28/2019] [Indexed: 12/11/2022]
Abstract
Grid cells provide a compelling example of a link between cellular activity and an abstract and difficult to define concept like space. Accordingly, a representational perspective on grid coding argues that neural grid coding underlies a fundamentally spatial metric. Recently, some theoretical proposals have suggested extending such a framework to nonspatial cognition as well, such as category learning. Here, we provide a critique of the frequently employed assumption of an isomorphism between patterns of neural activity (e.g., grid cells), mental representation, and behavior (e.g., navigation). Specifically, we question the strict isomorphism between these three levels and suggest that human spatial navigation is perhaps best characterized by a wide variety of both metric and nonmetric strategies. We offer an alternative perspective on how grid coding might relate to human spatial navigation, arguing that grid coding is part of a much larger conglomeration of neural activity patterns that dynamically tune to accomplish specific behavioral outputs.
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Affiliation(s)
- Arne D Ekstrom
- Department of Psychology, University of Arizona, Tucson, Arizona
| | | | - Derek J Huffman
- Center for Neuroscience, University of California, Davis, California
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16
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Park SW, Jang HJ, Kim M, Kwag J. Spatiotemporally random and diverse grid cell spike patterns contribute to the transformation of grid cell to place cell in a neural network model. PLoS One 2019; 14:e0225100. [PMID: 31725775 PMCID: PMC6855461 DOI: 10.1371/journal.pone.0225100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 10/29/2019] [Indexed: 12/13/2022] Open
Abstract
The medial entorhinal cortex and the hippocampus are brain regions specialized in spatial information processing. While an animal navigates around an environment, grid cells in the medial entorhinal cortex spike at multiple discrete locations, forming hexagonal grid patterns, and each grid cell is spatiotemporally dynamic with a different grid size, spacing, and orientation. In contrast, place cells in the hippocampus spike when an animal is at one or more specific locations, called a “place field”. While an animal traverses through a place field, the place cell’s spike phases relative to the hippocampal theta-frequency oscillation advance in phase, known as the “spike phase precession” phenomenon and each spike encodes the specific location within the place field. Interestingly, the medial entorhinal cortical grid cells and the hippocampal place cells are only one excitatory synapse apart. However, how the spatiotemporally dynamic multi-peaked grid cell activities are transformed into hippocampal place cell activities with spike phase precession phenomenon is yet unknown. To address this question, we construct an anatomically and physiologically realistic neural network model comprised of 10,000 grid cell models, each with a spatiotemporally dynamic grid patterns and a place cell model connected by excitatory synapses. Using this neural network model, we show that grid cells’ spike activities with spatiotemporally random and diverse grid orientation, spacing, and phases as inputs to place cell are able to generate a place field with spike phase precession. These results indicate that spatiotemporally random and diverse grid cell spike activities are essential for the formation of place cell activity observed in vivo.
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Affiliation(s)
- Sahn Woo Park
- Neural Computational Laboratory, Department of Brain and Cognitive Engineering, Korea University, Seoul, Korea
| | - Hyun Jae Jang
- Neural Computational Laboratory, Department of Brain and Cognitive Engineering, Korea University, Seoul, Korea
| | - Mincheol Kim
- Neural Computational Laboratory, Department of Brain and Cognitive Engineering, Korea University, Seoul, Korea
| | - Jeehyun Kwag
- Neural Computational Laboratory, Department of Brain and Cognitive Engineering, Korea University, Seoul, Korea
- * E-mail:
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17
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Nilssen ES, Doan TP, Nigro MJ, Ohara S, Witter MP. Neurons and networks in the entorhinal cortex: A reappraisal of the lateral and medial entorhinal subdivisions mediating parallel cortical pathways. Hippocampus 2019; 29:1238-1254. [PMID: 31408260 DOI: 10.1002/hipo.23145] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 06/29/2019] [Accepted: 07/11/2019] [Indexed: 12/31/2022]
Abstract
In this review, we aim to reappraise the organization of intrinsic and extrinsic networks of the entorhinal cortex with a focus on the concept of parallel cortical connectivity streams. The concept of two entorhinal areas, the lateral and medial entorhinal cortex, belonging to two parallel input-output streams mediating the encoding and storage of respectively what and where information hinges on the claim that a major component of their cortical connections is with the perirhinal cortex and postrhinal or parahippocampal cortex in, respectively, rodents or primates. In this scenario, the lateral entorhinal cortex and the perirhinal cortex are connectionally associated and likewise the postrhinal/parahippocampal cortex and the medial entorhinal cortex are partners. In contrast, here we argue that the connectivity matrix emphasizes the potential of substantial integration of cortical information through interactions between the two entorhinal subdivisions and between the perirhinal and postrhinal/parahippocampal cortices, but most importantly through a new observation that the postrhinal/parahippocampal cortex projects to both lateral and medial entorhinal cortex. We suggest that entorhinal inputs provide the hippocampus with high-order complex representations of the external environment, its stability, as well as apparent changes either as an inherent feature of a biological environment or as the result of navigating the environment. This thus indicates that the current connectional model of the parahippocampal region as part of the medial temporal lobe memory system needs to be revised.
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Affiliation(s)
- Eirik S Nilssen
- Kavli Institute for Systems Neuroscience, Centre for Neural Computation, Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Thanh P Doan
- Kavli Institute for Systems Neuroscience, Centre for Neural Computation, Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Maximiliano J Nigro
- Kavli Institute for Systems Neuroscience, Centre for Neural Computation, Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Shinya Ohara
- Kavli Institute for Systems Neuroscience, Centre for Neural Computation, Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, NTNU Norwegian University of Science and Technology, Trondheim, Norway
- Laboratory of Systems Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Menno P Witter
- Kavli Institute for Systems Neuroscience, Centre for Neural Computation, Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, NTNU Norwegian University of Science and Technology, Trondheim, Norway
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18
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Abstract
Spatial memory, the aspect of memory involving encoding and retrieval of information regarding one's environment and spatial orientation, is a complex biological function incorporating multiple neuronal networks. Hippocampus-dependent spatial memory is not innate and emerges during development in both humans and rodents. In children, nonhippocampal dependent egocentric (self-to-object) memory develops before hippocampal-dependent allocentric (object-to-object) memory. The onset of allocentric spatial memory abilities in children around 22 mo of age occurs at an age-equivalent time in rodents when spatially tuned grid and place cells arise from patterned activity propagating through the entorhinal-hippocampal circuit. Neuronal activity, often driven by specific sensory signals, is critical for the normal maturation of brain circuits This patterned activity fine-tunes synaptic connectivity of the network and drives the emergence of specific firing necessary for spatial memory. Whereas normal activity patterns are required for circuit maturation, aberrant neuronal activity during development can have major adverse consequences, disrupting the development of spatial memory. Seizures during infancy, involving massive bursts of synchronized network activity, result in impaired spatial memory when animals are tested as adolescents or adults. This impaired spatial memory is accompanied by alterations in spatial and temporal coding of place cells. The molecular mechanisms by which early-life seizures lead to disruptions at the cellular and network levels are now becoming better understood, and provide a target for intervention, potentially leading to improved cognitive outcome in individuals experiencing early-life seizures.
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Affiliation(s)
- Tallie Z Baram
- Department of Anatomy/Neurobiology, University of California-Irvine, Irvine, California 92697, USA
- Department of Pediatrics, University of California-Irvine, Irvine, California 92697, USA
- Department of Neurology, University of California-Irvine, Irvine, California 92697, USA
| | - Flavio Donato
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim 7491, Norway
- Biozentrum, Department of Cell Biology, University of Basel 4056, Switzerland
| | - Gregory L Holmes
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont 05401, USA
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19
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Gu Y, Lewallen S, Kinkhabwala AA, Domnisoru C, Yoon K, Gauthier JL, Fiete IR, Tank DW. A Map-like Micro-Organization of Grid Cells in the Medial Entorhinal Cortex. Cell 2018; 175:736-750.e30. [PMID: 30270041 PMCID: PMC6591153 DOI: 10.1016/j.cell.2018.08.066] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 07/31/2018] [Accepted: 08/29/2018] [Indexed: 11/20/2022]
Abstract
How the topography of neural circuits relates to their function remains unclear. Although topographic maps exist for sensory and motor variables, they are rarely observed for cognitive variables. Using calcium imaging during virtual navigation, we investigated the relationship between the anatomical organization and functional properties of grid cells, which represent a cognitive code for location during navigation. We found a substantial degree of grid cell micro-organization in mouse medial entorhinal cortex: grid cells and modules all clustered anatomically. Within a module, the layout of grid cells was a noisy two-dimensional lattice in which the anatomical distribution of grid cells largely matched their spatial tuning phases. This micro-arrangement of phases demonstrates the existence of a topographical map encoding a cognitive variable in rodents. It contributes to a foundation for evaluating circuit models of the grid cell network and is consistent with continuous attractor models as the mechanism of grid formation.
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Affiliation(s)
- Yi Gu
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA; Bezos Center for Neural Circuit Dynamics, Princeton University, NJ 08544, USA.
| | - Sam Lewallen
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA; Bezos Center for Neural Circuit Dynamics, Princeton University, NJ 08544, USA
| | - Amina A Kinkhabwala
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA; Bezos Center for Neural Circuit Dynamics, Princeton University, NJ 08544, USA
| | - Cristina Domnisoru
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA; Bezos Center for Neural Circuit Dynamics, Princeton University, NJ 08544, USA
| | - Kijung Yoon
- Center for Learning and Memory, University of Texas at Austin, Austin, TX 78712, USA; Department of Neuroscience, University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey L Gauthier
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA; Bezos Center for Neural Circuit Dynamics, Princeton University, NJ 08544, USA
| | - Ila R Fiete
- Center for Learning and Memory, University of Texas at Austin, Austin, TX 78712, USA; Department of Neuroscience, University of Texas at Austin, Austin, TX 78712, USA
| | - David W Tank
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA; Bezos Center for Neural Circuit Dynamics, Princeton University, NJ 08544, USA.
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20
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Park D, Bae S, Yoon TH, Ko J. Molecular Mechanisms of Synaptic Specificity: Spotlight on Hippocampal and Cerebellar Synapse Organizers. Mol Cells 2018; 41:373-380. [PMID: 29665671 PMCID: PMC5974614 DOI: 10.14348/molcells.2018.0081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 03/30/2018] [Accepted: 04/02/2018] [Indexed: 12/13/2022] Open
Abstract
Synapses and neural circuits form with exquisite specificity during brain development to allow the precise and appropriate flow of neural information. Although this property of synapses and neural circuits has been extensively investigated for more than a century, molecular mechanisms underlying this property are only recently being unveiled. Recent studies highlight several classes of cell-surface proteins as organizing hubs in building structural and functional architectures of specific synapses and neural circuits. In the present mini-review, we discuss recent findings on various synapse organizers that confer the distinct properties of specific synapse types and neural circuit architectures in mammalian brains, with a particular focus on the hippocampus and cerebellum.
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Affiliation(s)
- Dongseok Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
| | - Sungwon Bae
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
| | - Taek Han Yoon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
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21
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Chizhov AV, Amakhin DV, Zaizev AV, Magazanik LG. AMPAR-mediated Interictal Discharges in Neurons of Entorhinal Cortex: Experiment and Model. Dokl Biol Sci 2018; 479:47-50. [PMID: 29790025 DOI: 10.1134/s0012496618020011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Indexed: 06/08/2023]
Abstract
The mechanisms of interictal discharges (IID) were studied under the conditions of the 4-aminopyridine model of spontaneous epileptiform activity in surviving rat brain slice preparations. Addition of the agents blocking GABA and NMDA receptors failed to inhibit IID generation in the entorhinal cortex. A mathematical model of IID has been developed on the basis of the excitatory neuron interaction mediated by the AMPA receptor. Short-term synaptic depression and slow afterspike-hyperpolarization are the key factors required to terminate a single IID. The IID shape-determining factors have been identified. The experimental and model IID features correspond to each other.
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Affiliation(s)
- A V Chizhov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
- Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg, Russia.
| | - D V Amakhin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - A V Zaizev
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - L G Magazanik
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
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22
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Jun JJ, Steinmetz NA, Siegle JH, Denman DJ, Bauza M, Barbarits B, Lee AK, Anastassiou CA, Andrei A, Aydın Ç, Barbic M, Blanche TJ, Bonin V, Couto J, Dutta B, Gratiy SL, Gutnisky DA, Häusser M, Karsh B, Ledochowitsch P, Lopez CM, Mitelut C, Musa S, Okun M, Pachitariu M, Putzeys J, Rich PD, Rossant C, Sun WL, Svoboda K, Carandini M, Harris KD, Koch C, O'Keefe J, Harris TD. Fully integrated silicon probes for high-density recording of neural activity. Nature 2017; 551:232-236. [PMID: 29120427 PMCID: PMC5955206 DOI: 10.1038/nature24636] [Citation(s) in RCA: 943] [Impact Index Per Article: 134.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 10/16/2017] [Indexed: 12/24/2022]
Abstract
Sensory, motor and cognitive operations involve the coordinated action of large neuronal populations across multiple brain regions in both superficial and deep structures. Existing extracellular probes record neural activity with excellent spatial and temporal (sub-millisecond) resolution, but from only a few dozen neurons per shank. Optical Ca2+ imaging offers more coverage but lacks the temporal resolution needed to distinguish individual spikes reliably and does not measure local field potentials. Until now, no technology compatible with use in unrestrained animals has combined high spatiotemporal resolution with large volume coverage. Here we design, fabricate and test a new silicon probe known as Neuropixels to meet this need. Each probe has 384 recording channels that can programmably address 960 complementary metal-oxide-semiconductor (CMOS) processing-compatible low-impedance TiN sites that tile a single 10-mm long, 70 × 20-μm cross-section shank. The 6 × 9-mm probe base is fabricated with the shank on a single chip. Voltage signals are filtered, amplified, multiplexed and digitized on the base, allowing the direct transmission of noise-free digital data from the probe. The combination of dense recording sites and high channel count yielded well-isolated spiking activity from hundreds of neurons per probe implanted in mice and rats. Using two probes, more than 700 well-isolated single neurons were recorded simultaneously from five brain structures in an awake mouse. The fully integrated functionality and small size of Neuropixels probes allowed large populations of neurons from several brain structures to be recorded in freely moving animals. This combination of high-performance electrode technology and scalable chip fabrication methods opens a path towards recording of brain-wide neural activity during behaviour.
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Affiliation(s)
- James J. Jun
- HHMI Janelia Research Campus, 19700 Helix Dr., Ashburn, VA 20147
| | - Nicholas A. Steinmetz
- UCL Institute of Neurology, University College London, London WC1N 3BG, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6DE, UK
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Joshua H. Siegle
- Allen Institute for Brain Science, 615 Westlake Ave N, Seattle, WA 98109
| | - Daniel J. Denman
- Allen Institute for Brain Science, 615 Westlake Ave N, Seattle, WA 98109
| | - Marius Bauza
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
- Sainsbury Wellcome Center, University College London, London W1T 4JG, UK
| | - Brian Barbarits
- HHMI Janelia Research Campus, 19700 Helix Dr., Ashburn, VA 20147
| | - Albert K. Lee
- HHMI Janelia Research Campus, 19700 Helix Dr., Ashburn, VA 20147
| | | | | | - Çağatay Aydın
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001 Leuven Belgium
- KU Leuven, Department of Biology, Naamsestraat 59, 3000 Leuven, Belgium
| | - Mladen Barbic
- HHMI Janelia Research Campus, 19700 Helix Dr., Ashburn, VA 20147
| | - Timothy J. Blanche
- Allen Institute for Brain Science, 615 Westlake Ave N, Seattle, WA 98109
- White Matter LLC, Seattle, USA
| | - Vincent Bonin
- imec, Kapeldreef 75, 3001 Heverlee, Leuven Belgium
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001 Leuven Belgium
- KU Leuven, Department of Biology, Naamsestraat 59, 3000 Leuven, Belgium
- VIB, 3001 Leuven, Belgium
| | - João Couto
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001 Leuven Belgium
- KU Leuven, Department of Biology, Naamsestraat 59, 3000 Leuven, Belgium
| | | | - Sergey L. Gratiy
- Allen Institute for Brain Science, 615 Westlake Ave N, Seattle, WA 98109
| | | | - Michael Häusser
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6DE, UK
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
| | - Bill Karsh
- HHMI Janelia Research Campus, 19700 Helix Dr., Ashburn, VA 20147
| | | | | | - Catalin Mitelut
- Allen Institute for Brain Science, 615 Westlake Ave N, Seattle, WA 98109
| | - Silke Musa
- imec, Kapeldreef 75, 3001 Heverlee, Leuven Belgium
| | - Michael Okun
- UCL Institute of Neurology, University College London, London WC1N 3BG, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6DE, UK
- Centre for Systems Neuroscience, University of Leicester, Leicester LE1 7QR, UK
| | - Marius Pachitariu
- UCL Institute of Neurology, University College London, London WC1N 3BG, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6DE, UK
| | - Jan Putzeys
- imec, Kapeldreef 75, 3001 Heverlee, Leuven Belgium
| | - P. Dylan Rich
- HHMI Janelia Research Campus, 19700 Helix Dr., Ashburn, VA 20147
| | - Cyrille Rossant
- UCL Institute of Neurology, University College London, London WC1N 3BG, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6DE, UK
| | - Wei-lung Sun
- HHMI Janelia Research Campus, 19700 Helix Dr., Ashburn, VA 20147
| | - Karel Svoboda
- HHMI Janelia Research Campus, 19700 Helix Dr., Ashburn, VA 20147
| | - Matteo Carandini
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Kenneth D. Harris
- UCL Institute of Neurology, University College London, London WC1N 3BG, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6DE, UK
| | - Christof Koch
- Allen Institute for Brain Science, 615 Westlake Ave N, Seattle, WA 98109
| | - John O'Keefe
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
- Sainsbury Wellcome Center, University College London, London W1T 4JG, UK
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23
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Abstract
Spatial cognition in mammals is thought to rely on the activity of grid cells in the entorhinal cortex, yet the fundamental principles underlying the origin of grid-cell firing are still debated. Grid-like patterns could emerge via Hebbian learning and neuronal adaptation, but current computational models remained too abstract to allow direct confrontation with experimental data. Here, we propose a single-cell spiking model that generates grid firing fields via spike-rate adaptation and spike-timing dependent plasticity. Through rigorous mathematical analysis applicable in the linear limit, we quantitatively predict the requirements for grid-pattern formation, and we establish a direct link to classical pattern-forming systems of the Turing type. Our study lays the groundwork for biophysically-realistic models of grid-cell activity.
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Affiliation(s)
- Tiziano D’Albis
- Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Richard Kempter
- Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
- Einstein Center for Neurosciences Berlin, Berlin, Germany
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24
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Grieves RM, Duvelle É, Wood ER, Dudchenko PA. Field repetition and local mapping in the hippocampus and the medial entorhinal cortex. J Neurophysiol 2017; 118:2378-2388. [PMID: 28814638 PMCID: PMC5646201 DOI: 10.1152/jn.00933.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 07/20/2017] [Accepted: 07/20/2017] [Indexed: 11/22/2022] Open
Abstract
Hippocampal place cells support spatial cognition and are thought to form the neural substrate of a global "cognitive map." A widely held view is that parts of the hippocampus also underlie the ability to separate patterns or to provide different neural codes for distinct environments. However, a number of studies have shown that in environments composed of multiple, repeating compartments, place cells and other spatially modulated neurons show the same activity in each local area. This repetition of firing fields may reflect pattern completion and may make it difficult for animals to distinguish similar local environments. In this review we 1) highlight some of the navigation difficulties encountered by humans in repetitive environments, 2) summarize literature demonstrating that place and grid cells represent local and not global space, and 3) attempt to explain the origin of these phenomena. We argue that the repetition of firing fields can be a useful tool for understanding the relationship between grid cells in the entorhinal cortex and place cells in the hippocampus, the spatial inputs shared by these cells, and the propagation of spatially related signals through these structures.
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Affiliation(s)
- Roddy M Grieves
- Institute of Behavioural Neuroscience, Department of Experimental Psychology, University College London, London, United Kingdom
| | - Éléonore Duvelle
- Institute of Behavioural Neuroscience, Department of Experimental Psychology, University College London, London, United Kingdom
| | - Emma R Wood
- Centre for Cognitive and Neural Systems, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom; and
| | - Paul A Dudchenko
- Centre for Cognitive and Neural Systems, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom; and
- Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
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25
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Roy DS, Kitamura T, Okuyama T, Ogawa SK, Sun C, Obata Y, Yoshiki A, Tonegawa S. Distinct Neural Circuits for the Formation and Retrieval of Episodic Memories. Cell 2017; 170:1000-1012.e19. [PMID: 28823555 PMCID: PMC5586038 DOI: 10.1016/j.cell.2017.07.013] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/01/2017] [Accepted: 07/12/2017] [Indexed: 01/26/2023]
Abstract
The formation and retrieval of a memory is thought to be accomplished by activation and reactivation, respectively, of the memory-holding cells (engram cells) by a common set of neural circuits, but this hypothesis has not been established. The medial temporal-lobe system is essential for the formation and retrieval of episodic memory for which individual hippocampal subfields and entorhinal cortex layers contribute by carrying out specific functions. One subfield whose function is poorly known is the subiculum. Here, we show that dorsal subiculum and the circuit, CA1 to dorsal subiculum to medial entorhinal cortex layer 5, play a crucial role selectively in the retrieval of episodic memories. Conversely, the direct CA1 to medial entorhinal cortex layer 5 circuit is essential specifically for memory formation. Our data suggest that the subiculum-containing detour loop is dedicated to meet the requirements associated with recall such as rapid memory updating and retrieval-driven instinctive fear responses.
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Affiliation(s)
- Dheeraj S Roy
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Takashi Kitamura
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Teruhiro Okuyama
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sachie K Ogawa
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Chen Sun
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yuichi Obata
- RIKEN BioResource Center, 3-1-1 Koyadai, Ibaraki 305-0074, Japan
| | - Atsushi Yoshiki
- RIKEN BioResource Center, 3-1-1 Koyadai, Ibaraki 305-0074, Japan
| | - Susumu Tonegawa
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
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26
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Cilz NI, Lei S. Histamine facilitates GABAergic transmission in the rat entorhinal cortex: Roles of H 1 and H 2 receptors, Na + -permeable cation channels, and inward rectifier K + channels. Hippocampus 2017; 27:613-631. [PMID: 28188663 PMCID: PMC5793915 DOI: 10.1002/hipo.22718] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/07/2017] [Indexed: 12/11/2022]
Abstract
In the brain, histamine (HA) serves as a neuromodulator and a neurotransmitter released from the tuberomammillary nucleus (TMN). HA is involved in wakefulness, thermoregulation, energy homeostasis, nociception, and learning and memory. The medial entorhinal cortex (MEC) receives inputs from the TMN and expresses HA receptors (H1 , H2 , and H3 ). We investigated the effects of HA on GABAergic transmission in the MEC and found that HA significantly increased the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) with an EC50 of 1.3 µM, but failed to significantly alter sIPSC amplitude. HA-induced increases in sIPSC frequency were sensitive to tetrodotoxin (TTX), required extracellular Ca2+ , and persisted when GDP-β-S, a G-protein inactivator, was applied postsynaptically via the recording pipettes, indicating that HA increased GABA release by facilitating the excitability of GABAergic interneurons in the MEC. Recordings from local MEC interneurons revealed that HA significantly increased their excitability as determined by membrane depolarization, generation of an inward current at -65 mV, and augmentation of action potential firing frequency. Both H1 and H2 receptors were involved in HA-induced increases in sIPSCs and interneuron excitability. Immunohistochemical staining showed that both H1 and H2 receptors are expressed on GABAergic interneurons in the MEC. HA-induced depolarization of interneurons involved a mixed ionic mechanism including activation of a Na+ -permeable cation channel and inhibition of a cesium-sensitive inward rectifier K+ channel, although HA also inhibited the delayed rectifier K+ channels. Our results may provide a cellular mechanism, at least partially, to explain the roles of HA in the brain. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Nicholas I Cilz
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota
| | - Saobo Lei
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota
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27
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Hönigsperger C, Nigro MJ, Storm JF. Physiological roles of Kv2 channels in entorhinal cortex layer II stellate cells revealed by Guangxitoxin-1E. J Physiol 2017; 595:739-757. [PMID: 27562026 PMCID: PMC5285721 DOI: 10.1113/jp273024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/19/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Kv2 channels underlie delayed-rectifier potassium currents in various neurons, although their physiological roles often remain elusive. Almost nothing is known about Kv2 channel functions in medial entorhinal cortex (mEC) neurons, which are involved in representing space, memory formation, epilepsy and dementia. Stellate cells in layer II of the mEC project to the hippocampus and are considered to be space-representing grid cells. We used the new Kv2 blocker Guangxitoxin-1E (GTx) to study Kv2 functions in these neurons. Voltage clamp recordings from mEC stellate cells in rat brain slices showed that GTx inhibited delayed-rectifier K+ current but not transient A-type current. In current clamp, GTx had multiple effects: (i) increasing excitability and bursting at moderate spike rates but reducing firing at high rates; (ii) enhancing after-depolarizations; (iii) reducing the fast and medium after-hyperpolarizations; (iv) broadening action potentials; and (v) reducing spike clustering. GTx is a useful tool for studying Kv2 channels and their functions in neurons. ABSTRACT The medial entorhinal cortex (mEC) is strongly involved in spatial navigation, memory, dementia and epilepsy. Although potassium channels shape neuronal activity, their roles in mEC are largely unknown. We used the new Kv2 blocker Guangxitoxin-1E (GTx; 10-100 nm) in rat brain slices to investigate Kv2 channel functions in mEC layer II stellate cells (SCs). These neurons project to the hippocampus and are considered to be grid cells representing space. Voltage clamp recordings from SCs nucleated patches showed that GTx inhibited a delayed rectifier K+ current activating beyond -30 mV but not transient A-type current. In current clamp, GTx (i) had almost no effect on the first action potential but markedly slowed repolarization of late spikes during repetitive firing; (ii) enhanced the after-depolarization (ADP); (iii) reduced fast and medium after-hyperpolarizations (AHPs); (iv) strongly enhanced burst firing and increased excitability at moderate spike rates but reduced spiking at high rates; and (v) reduced spike clustering and rebound potentials. The changes in bursting and excitability were related to the altered ADPs and AHPs. Kv2 channels strongly shape the activity of mEC SCs by affecting spike repolarization, after-potentials, excitability and spike patterns. GTx is a useful tool and may serve to further clarify Kv2 channel functions in neurons. We conclude that Kv2 channels in mEC SCs are important determinants of intrinsic properties that allow these neurons to produce spatial representation. The results of the present study may also be important for the accurate modelling of grid cells.
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Affiliation(s)
| | - Maximiliano J. Nigro
- Department of PhysiologyInstitute of Basal Medical SciencesUniversity of OsloOsloNorway
- Department of Physiology and NeuroscienceNeuroscience InstituteNew York UniversityNew York, NYUSA
| | - Johan F. Storm
- Department of PhysiologyInstitute of Basal Medical SciencesUniversity of OsloOsloNorway
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28
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Keene CS, Bladon J, McKenzie S, Liu CD, O'Keefe J, Eichenbaum H. Complementary Functional Organization of Neuronal Activity Patterns in the Perirhinal, Lateral Entorhinal, and Medial Entorhinal Cortices. J Neurosci 2016; 36:3660-75. [PMID: 27030753 PMCID: PMC4812128 DOI: 10.1523/jneurosci.4368-15.2016] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 02/16/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED It is commonly conceived that the cortical areas of the hippocampal region are functionally divided into the perirhinal cortex (PRC) and the lateral entorhinal cortex (LEC), which selectively process object information; and the medial entorhinal cortex (MEC), which selectively processes spatial information. Contrary to this notion, in rats performing a task that demands both object and spatial information processing, single neurons in PRC, LEC, and MEC, including those in both superficial and deep cortical areas and in grid, border, and head direction cells of MEC, have a highly similar range of selectivity to object and spatial dimensions of the task. By contrast, representational similarity analysis of population activity reveals a key distinction in the organization of information in these areas, such that PRC and LEC populations prioritize object over location information, whereas MEC populations prioritize location over object information. These findings bring to the hippocampal system a growing emphasis on population analyses as a powerful tool for characterizing neural representations supporting cognition and memory. SIGNIFICANCE STATEMENT Contrary to the common view that brain regions in the "what" and "where" streams distinctly process object and spatial cues, respectively, we found that both streams encode both object and spatial information but distinctly organize memories for objects and space. Specifically, perirhinal cortex and lateral entorhinal cortex represent objects and, within the object-specific representations, the locations where they occur. Conversely, medial entorhinal cortex represents relevant locations and, within those spatial representations, the objects that occupy them. Furthermore, these findings reach beyond simple notions of perirhinal cortex and lateral entorhinal cortex neurons as object detectors and MEC neurons as position detectors, and point to a more complex organization of memory representations within the medial temporal lobe system.
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Affiliation(s)
- Christopher S Keene
- Center for Memory and Brain, Boston University, Boston, Massachusetts 02215, and
| | - John Bladon
- Center for Memory and Brain, Boston University, Boston, Massachusetts 02215, and
| | - Sam McKenzie
- The Neuroscience Institute, New York University Langone Medical Center, New York, New York 10016
| | - Cindy D Liu
- Center for Memory and Brain, Boston University, Boston, Massachusetts 02215, and
| | - Joseph O'Keefe
- Center for Memory and Brain, Boston University, Boston, Massachusetts 02215, and
| | - Howard Eichenbaum
- Center for Memory and Brain, Boston University, Boston, Massachusetts 02215, and
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29
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Boehlen A, Heinemann U, Henneberger C. Hierarchical spike clustering analysis for investigation of interneuron heterogeneity. Neurosci Lett 2016; 619:86-91. [PMID: 26987719 DOI: 10.1016/j.neulet.2016.03.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/02/2016] [Accepted: 03/11/2016] [Indexed: 11/18/2022]
Abstract
Action potentials represent the output of a neuron. Especially interneurons display a variety of discharge patterns ranging from regular action potential firing to prominent spike clustering or stuttering. The mechanisms underlying this heterogeneity remain incompletely understood. We established hierarchical cluster analysis of spike trains as a measure of spike clustering. A clustering index was calculated from action potential trains recorded in the whole-cell patch clamp configuration from hippocampal (CA1, stratum radiatum) and entorhinal (medial entorhinal cortex, layer 2) interneurons in acute slices and simulated data. Prominent, region-dependent, but also variable spike clustering was detected using this measure. Further analysis revealed a strong positive correlation between spike clustering and membrane potentials oscillations but an inverse correlation with neuronal resonance. Furthermore, clustering was more pronounced when the balance between fast-activating K(+) currents, assessed by the spike repolarisation time, and hyperpolarization-activated currents, gauged by the size of the sag potential, was shifted in favour of fast K(+) currents. Simulations of spike clustering confirmed that variable ratios of fast K(+) and hyperpolarization-activated currents could underlie different degrees of spike clustering and could thus be crucial for temporally structuring interneuron spike output.
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Affiliation(s)
- Anne Boehlen
- Institute of Neurophysiology, Charité, Berlin, Germany; Institute of Cellular Neurosciences, University of Bonn Medical School, Bonn, Germany.
| | - Uwe Heinemann
- Institute of Neurophysiology, Charité, Berlin, Germany; Excellence Cluster NeuroCure, Berlin, Germany
| | - Christian Henneberger
- Institute of Cellular Neurosciences, University of Bonn Medical School, Bonn, Germany; German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany; Institute of Neurology, University College London, London, United Kingdom.
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30
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Abstract
The discovery of grid cells in the entorhinal cortex has both elucidated our understanding of spatial representations in the brain, and germinated a large number of theoretical models regarding the mechanisms of these cells' striking spatial firing characteristics. These models cross multiple neurobiological levels that include intrinsic membrane resonance, dendritic integration, after hyperpolarization characteristics and attractor dynamics. Despite the breadth of the models, to our knowledge, parallels can be drawn between grid fields and other temporal dynamics observed in nature, much of which was described by Art Winfree and colleagues long before the initial description of grid fields. Using theoretical and mathematical investigations of oscillators, in a wide array of mediums far from the neurobiology of grid cells, Art Winfree has provided a substantial amount of research with significant and profound similarities. These theories provide specific inferences into the biological mechanisms and extraordinary resemblances across phenomenon. Therefore, this manuscript provides a novel interpretation on the phenomenon of grid fields, from the perspective of coupled oscillators, postulating that grid fields are the spatial representation of phase resetting curves in the brain. In contrast to prior models of gird cells, the current manuscript provides a sketch by which a small network of neurons, each with oscillatory components can operate to form grid cells, perhaps providing a unique hybrid between the competing attractor neural network and oscillatory interference models. The intention of this new interpretation of the data is to encourage novel testable hypotheses.
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Affiliation(s)
- Andrey L. Shilnikov
- Neuroscience Institute and Department of Mathematics and Statistics, Georgia State UniversityAtlanta, GA, USA
- Institute for Information Technology, Mathematics and Mechanics, Lobachevsky State University of Nizhni NovgorodNizhni Novgorod, Russia
| | - Andrew Porter Maurer
- Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of FloridaGainesville, FL, USA
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31
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Naumann RK, Ray S, Prokop S, Las L, Heppner FL, Brecht M. Conserved size and periodicity of pyramidal patches in layer 2 of medial/caudal entorhinal cortex. J Comp Neurol 2016; 524:783-806. [PMID: 26223342 PMCID: PMC5014138 DOI: 10.1002/cne.23865] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/16/2015] [Accepted: 07/17/2015] [Indexed: 11/29/2022]
Abstract
To understand the structural basis of grid cell activity, we compare medial entorhinal cortex architecture in layer 2 across five mammalian species (Etruscan shrews, mice, rats, Egyptian fruit bats, and humans), bridging ∼100 million years of evolutionary diversity. Principal neurons in layer 2 are divided into two distinct cell types, pyramidal and stellate, based on morphology, immunoreactivity, and functional properties. We confirm the existence of patches of calbindin-positive pyramidal cells across these species, arranged periodically according to analyses techniques like spatial autocorrelation, grid scores, and modifiable areal unit analysis. In rodents, which show sustained theta oscillations in entorhinal cortex, cholinergic innervation targeted calbindin patches. In bats and humans, which only show intermittent entorhinal theta activity, cholinergic innervation avoided calbindin patches. The organization of calbindin-negative and calbindin-positive cells showed marked differences in entorhinal subregions of the human brain. Layer 2 of the rodent medial and the human caudal entorhinal cortex were structurally similar in that in both species patches of calbindin-positive pyramidal cells were superimposed on scattered stellate cells. The number of calbindin-positive neurons in a patch increased from ∼80 in Etruscan shrews to ∼800 in humans, only an ∼10-fold over a 20,000-fold difference in brain size. The relatively constant size of calbindin patches differs from cortical modules such as barrels, which scale with brain size. Thus, selective pressure appears to conserve the distribution of stellate and pyramidal cells, periodic arrangement of calbindin patches, and relatively constant neuron number in calbindin patches in medial/caudal entorhinal cortex.
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Affiliation(s)
- Robert K. Naumann
- Bernstein Center for Computational NeuroscienceHumboldt University of Berlin10115BerlinGermany
- Max‐Planck‐Institute for Brain ResearchMax‐von‐Laue‐Str. 460438Frankfurt am MainGermany
| | - Saikat Ray
- Bernstein Center for Computational NeuroscienceHumboldt University of Berlin10115BerlinGermany
| | - Stefan Prokop
- Neuropathology Institute, Charité Medical School10117BerlinGermany
| | - Liora Las
- Department of NeurobiologyWeizmann Institute of ScienceRehovot76100Israel
| | - Frank L. Heppner
- Neuropathology Institute, Charité Medical School10117BerlinGermany
| | - Michael Brecht
- Bernstein Center for Computational NeuroscienceHumboldt University of Berlin10115BerlinGermany
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32
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Abstract
Grid cells in entorhinal and parahippocampal cortices contribute to a network, centered on the hippocampal place cell system, that constructs a representation of spatial context for use in navigation and memory. In doing so, they use metric cues such as the distance and direction of nearby boundaries to position and orient their firing field arrays (grids). The present study investigated whether they also use purely nonmetric "context" information such as color and odor of the environment. We found that, indeed, purely nonmetric cues--sufficiently salient to cause changes in place cell firing patterns--can regulate grid positioning; they do so independently of orientation, and thus interact with linear but not directional spatial inputs. Grid cells responded homogeneously to context changes. We suggest that the grid and place cell networks receive context information directly and also from each other; the information is used by place cells to compute the final decision of the spatial system about which context the animal is in, and by grid cells to help inform the system about where the animal is within it.
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Affiliation(s)
- Elizabeth Marozzi
- Department of Experimental Psychology, University College London, London WC1H 0AP, UK
| | - Lin Lin Ginzberg
- Department of Experimental Psychology, University College London, London WC1H 0AP, UK Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Andrea Alenda
- Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, UK
| | - Kate J Jeffery
- Department of Experimental Psychology, University College London, London WC1H 0AP, UK
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33
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Rueckemann JW, DiMauro AJ, Rangel LM, Han X, Boyden ES, Eichenbaum H. Transient optogenetic inactivation of the medial entorhinal cortex biases the active population of hippocampal neurons. Hippocampus 2015; 26:246-60. [PMID: 26299904 DOI: 10.1002/hipo.22519] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 08/20/2015] [Indexed: 11/07/2022]
Abstract
The mechanisms that enable the hippocampal network to express the appropriate spatial representation for a particular circumstance are not well understood. Previous studies suggest that the medial entorhinal cortex (MEC) may have a role in reproducibly selecting the hippocampal representation of an environment. To examine how ongoing MEC activity is continually integrated by the hippocampus, we performed transient unilateral optogenetic inactivations of the MEC while simultaneously recording place cell activity in CA1. Inactivation of the MEC caused a partial remapping in the CA1 population without diminishing the degree of spatial tuning across the active cell assembly. These changes remained stable irrespective of intermittent disruption of MEC input, indicating that while MEC input is integrated over long time scales to bias the active population, there are mechanisms for stabilizing the population of active neurons independent of the MEC. We find that MEC inputs to the hippocampus shape its ongoing activity by biasing the participation of the neurons in the active network, thereby influencing how the hippocampus selectively represents information.
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Affiliation(s)
- Jon W Rueckemann
- Center for Memory and Brain, Boston University, Boston, Massachusetts
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA
| | - Audrey J DiMauro
- Center for Memory and Brain, Boston University, Boston, Massachusetts
- Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Lara M Rangel
- Center for Memory and Brain, Boston University, Boston, Massachusetts
| | - Xue Han
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Edward S Boyden
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Howard Eichenbaum
- Center for Memory and Brain, Boston University, Boston, Massachusetts
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34
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Abstract
In this issue of Neuron, Hardcastle et al. (2015) show that the spatial firing patterns of grid cells accumulate error, drifting coherently, until reset by encounters with environmental boundaries. These results reveal important aspects of the neural dynamics of self-localization from self-motion and environmental information.
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Affiliation(s)
- Robin Hayman
- UCL Institute of Cognitive Neuroscience, London WC1N 3AR, UK; UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Neil Burgess
- UCL Institute of Cognitive Neuroscience, London WC1N 3AR, UK; UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.
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35
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Abstract
The discoveries of "place cells" in the hippocampus and "grid cells" in the entorhinal cortex are landmark achievements in relating behavior to neural activity, permitting analysis of a powerful system for spatial representation in the brain. The contributions of this work include not only the empirical findings but also the approach this work pioneered of examining neural activity in complex behaviors with real ecological validity in freely moving animals, and of attempting to place the findings in the larger context of how the neural representations of space are used in service of real-world behavior, namely what the Nobel committee described as permitting us to "navigate our way through a complex environment." These discoveries and approaches have had far-ranging impact on and implications for work in human cognitive neuroscience, where we see (1) confirmation in humans that the hippocampus and overlying MTL cortex are critically engaged in supporting a relational representation of space, and that it can be used for flexible spatial navigation and (2) evidence that these regions are also critically involved in aspects of relational memory not limited to space, and in the flexible use of hippocampal memory extending beyond spatial navigation. Recent work, using tasks that emphasize the requirement for the active use of memory in online processing, just as spatial navigation has long placed such a requirement on rodents, suggests that the hippocampus and related MTL cortex can support the navigating of environments even more complex than what is needed in spatial navigation. It allows us to use memory in guiding upcoming actions and choices to act optimally in and on the world, permitting us to navigate life in all its beautiful complexity.
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Affiliation(s)
- Neal J. Cohen
- Department of Psychology, Neuroscience Program, and Beckman Institute, University of Illinois at Urbana-Champaign, Illinois
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36
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Hardcastle K, Ganguli S, Giocomo LM. Environmental boundaries as an error correction mechanism for grid cells. Neuron 2015; 86:827-39. [PMID: 25892299 DOI: 10.1016/j.neuron.2015.03.039] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/17/2014] [Accepted: 03/17/2015] [Indexed: 11/19/2022]
Abstract
Medial entorhinal grid cells fire in periodic, hexagonally patterned locations and are proposed to support path-integration-based navigation. The recursive nature of path integration results in accumulating error and, without a corrective mechanism, a breakdown in the calculation of location. The observed long-term stability of grid patterns necessitates that the system either performs highly precise internal path integration or implements an external landmark-based error correction mechanism. To distinguish these possibilities, we examined grid cells in behaving rodents as they made long trajectories across an open arena. We found that error accumulates relative to time and distance traveled since the animal last encountered a boundary. This error reflects coherent drift in the grid pattern. Further, interactions with boundaries yield direction-dependent error correction, suggesting that border cells serve as a neural substrate for error correction. These observations, combined with simulations of an attractor network grid cell model, demonstrate that landmarks are crucial to grid stability.
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Affiliation(s)
- Kiah Hardcastle
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA.
| | - Surya Ganguli
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA; Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Lisa M Giocomo
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA.
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37
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Abstract
The 2014 Nobel Prize for Physiology or Medicine was awarded for the discoveries that have elucidated the components of the internal positioning system that is centered on the hippocampus and entorhinal cortex. Here I provide a less than objective discussion of the importance of these accomplishments to systems neuroscience. By identifying positioning components like place, direction, distance, borders and the like, the field is given the opportunity to have a shot at piecing together how these components are integrated into the synthetic positioning sense. We are also given what is in my view, the most experimentally accessible and therefore potentially understandable, cognitive representation. Lest we feel too confident in the completeness of our understanding, and to inspire redoubled curiosity, I briefly describe a preliminary observation from our work with the psychosis-inducing drug phencyclidine (PCP). While PCP does not disturb where individual place cells fire, it dramatically discoordinates how these cells discharge together in time. Trying to understand how the positioning component cells are coordinated to provide useful knowledge is an exciting and tenable problem to be working on.
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Affiliation(s)
- André A Fenton
- Center for Neural Science, New York University, New York
- Department of Physiology and Pharmacology, Robert F. Furchgott Center for Neural and Behavioral Science, SUNY Downstate Medical Center, New York
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38
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Abstract
We study the statistics of spike trains of simultaneously recorded grid cells in freely behaving rats. We evaluate pairwise correlations between these cells and, using a maximum entropy kinetic pairwise model (kinetic Ising model), study their functional connectivity. Even when we account for the covariations in firing rates due to overlapping fields, both the pairwise correlations and functional connections decay as a function of the shortest distance between the vertices of the spatial firing pattern of pairs of grid cells, i.e. their phase difference. They take positive values between cells with nearby phases and approach zero or negative values for larger phase differences. We find similar results also when, in addition to correlations due to overlapping fields, we account for correlations due to theta oscillations and head directional inputs. The inferred connections between neurons in the same module and those from different modules can be both negative and positive, with a mean close to zero, but with the strongest inferred connections found between cells of the same module. Taken together, our results suggest that grid cells in the same module do indeed form a local network of interconnected neurons with a functional connectivity that supports a role for attractor dynamics in the generation of grid pattern. The way mammals navigate in space is hypothesized to depend on neural structures in the temporal lobe including the hippocampus and medial entorhinal cortex (MEC). In particular, grid cells, neurons whose firing is mostly restricted to regions of space that form a hexagonal pattern, are believed to be an important part of this circuitry. Despite several years of work, not much is known about the correlated activity of neurons in the MEC and how grid cells are functionally coupled to each other. Here, we have taken a statistical approach to these questions and studied pairwise correlations and functional connections between simultaneously recorded grid cells. Through careful statistical analysis, we demonstrate that grid cells with nearby firing vertices tend to have positive effects on eliciting responses in each other, while those further apart tend to have inhibitory or no effects. Cells that respond similarly to manipulations of the environment are considered to belong to the same module. Cells belonging to a module have stronger interactions with each other than those in different modules. These results are consistent with and shed light on the population-based mechanisms suggested by models for the generation of grid cell firing.
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Affiliation(s)
- Benjamin Dunn
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, NTNU, Trondheim, Norway
| | - Maria Mørreaunet
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, NTNU, Trondheim, Norway
| | - Yasser Roudi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, NTNU, Trondheim, Norway
- Nordita, KTH and Stockholm University, Stockholm, Sweden
- * E-mail:
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39
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Bienvenu TCM, Busti D, Micklem BR, Mansouri M, Magill PJ, Ferraguti F, Capogna M. Large intercalated neurons of amygdala relay noxious sensory information. J Neurosci 2015; 35:2044-57. [PMID: 25653362 PMCID: PMC4315833 DOI: 10.1523/jneurosci.1323-14.2015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 11/07/2014] [Accepted: 11/13/2014] [Indexed: 01/03/2023] Open
Abstract
Various GABAergic neuron types of the amygdala cooperate to control principal cell firing during fear-related and other behaviors, and understanding their specialized roles is important. Among GABAergic neurons, the so-called intercalated cells (ITCcs) are critically involved in the expression and extinction of fear memory. Tightly clustered small-sized spiny neurons constitute the majority of ITCcs, but they are surrounded by sparse, larger neurons (L-ITCcs) for which very little information is known. We report here a detailed neurochemical, structural and physiological characterization of rat L-ITCcs, as identified with juxtacellular recording/labeling in vivo. We supplement these data with anatomical and neurochemical analyses of nonrecorded L-ITCcs. We demonstrate that L-ITCcs are GABAergic, and strongly express metabotropic glutamate receptor 1α and GABAA receptor α1 subunit, together with moderate levels of parvalbumin. Furthermore, L-ITCcs are innervated by fibers enriched with metabotropic glutamate receptors 7a and/or 8a. In contrast to small-sized spiny ITCcs, L-ITCcs possess thick, aspiny dendrites, have highly branched, long-range axonal projections, and innervate interneurons in the basolateral amygdaloid complex. The axons of L-ITCcs also project to distant brain areas, such as the perirhinal, entorhinal, and endopiriform cortices. In vivo recorded L-ITCcs are strongly activated by noxious stimuli, such as hindpaw pinches or electrical footshocks. Consistent with this, we observed synaptic contacts on L-ITCc dendrites from nociceptive intralaminar thalamic nuclei. We propose that, during salient sensory stimulation, L-ITCcs disinhibit local and distant principal neurons, acting as "hub cells," to orchestrate the activity of a distributed network.
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Affiliation(s)
- Thomas C M Bienvenu
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, United Kingdom, and
| | - Daniela Busti
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Benjamin R Micklem
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, United Kingdom, and
| | - Mahnaz Mansouri
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Peter J Magill
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, United Kingdom, and
| | - Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Marco Capogna
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, United Kingdom, and
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40
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Abstract
Grid cells in the medial entorhinal cortex encode space with firing fields that are arranged on the nodes of spatial hexagonal lattices. Potential candidates to read out the space information of this grid code and to combine it with other sensory cues are hippocampal place cells. In this paper, we investigate a population of grid cells providing feed-forward input to place cells. The capacity of the underlying synaptic transformation is determined by both spatial acuity and the number of different spatial environments that can be represented. The codes for different environments arise from phase shifts of the periodical entorhinal cortex patterns that induce a global remapping of hippocampal place fields, i.e., a new random assignment of place fields for each environment. If only a single environment is encoded, the grid code can be read out at high acuity with only few place cells. A surplus in place cells can be used to store a space code for more environments via remapping. The number of stored environments can be increased even more efficiently by stronger recurrent inhibition and by partitioning the place cell population such that learning affects only a small fraction of them in each environment. We find that the spatial decoding acuity is much more resilient to multiple remappings than the sparseness of the place code. Since the hippocampal place code is sparse, we thus conclude that the projection from grid cells to the place cells is not using its full capacity to transfer space information. Both populations may encode different aspects of space. The mammalian brain represents space in the population of hippocampal place cells as well as in the population of medial entorhinal cortex grid cells. Since both populations are active at the same time, space information has to be synchronized between the two. Both brain areas are reciprocally connected, and it is unclear how the two codes influence each other. In this paper, we analyze a theoretical model of how a place code processes inputs from the grid cell population. The model shows that the sparseness of the place code poses a much stronger constraint than maximal information transfer. We thus conclude that the potentially high spatial acuity of the grid code cannot be efficiently conveyed to a sparse place cell population and thus propose that sparseness and spatial acuity are two independent objectives of the neuronal place representation.
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Affiliation(s)
- Axel Kammerer
- Department Biologie II, Ludwig-Maximilians-Universität München, Planegg, Germany
- Graduate School for Systemic Neurosciences, Ludwig-Maximilians-Universität München, Planegg, Germany
| | - Christian Leibold
- Department Biologie II, Ludwig-Maximilians-Universität München, Planegg, Germany
- * E-mail:
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41
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Luo FL, Yang N, He C, Li HL, Li C, Chen F, Xiong JX, Hu ZA, Zhang J. Exposure to extremely low frequency electromagnetic fields alters the calcium dynamics of cultured entorhinal cortex neurons. Environ Res 2014; 135:236-246. [PMID: 25462671 DOI: 10.1016/j.envres.2014.09.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 08/25/2014] [Accepted: 09/13/2014] [Indexed: 06/04/2023]
Abstract
Previous studies have revealed that extremely low frequency electromagnetic field (ELF-EMF) exposure affects neuronal dendritic spine density and NMDAR and AMPAR subunit expressions in the entorhinal cortex (EC). Although calcium signaling has a critical role in control of EC neuronal functions, however, it is still unclear whether the ELF-EMF exposure affects the EC neuronal calcium homeostasis. In the present study, using whole-cell recording and calcium imaging, we record the whole-cell inward currents that contain the voltage-gated calcium currents and show that ELF-EMF (50Hz, 1mT or 3mT, lasting 24h) exposure does not influence these currents. Next, we specifically isolate the high-voltage activated (HVA) and low-voltage activated (LVA) calcium channels-induced currents. Similarly, the activation and inactivation characteristics of these membrane calcium channels are also not influenced by ELF-EMF. Importantly, ELF-EMF exposure reduces the maximum amplitude of the high-K(+)-evoked calcium elevation in EC neurons, which is abolished by thapsigargin, a Ca(2+) ATPase inhibitor, to empty the intracellular calcium stores of EC neurons. Together, these findings indicate that ELF-EMF exposure specifically influences the intracellular calcium dynamics of cultural EC neurons via a calcium channel-independent mechanism.
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Affiliation(s)
- Fen-Lan Luo
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Nian Yang
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Chao He
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Hong-Li Li
- Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, PR China
| | - Chao Li
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Fang Chen
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Jia-Xiang Xiong
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Zhi-An Hu
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
| | - Jun Zhang
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
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42
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Unichenko P, Yang JW, Luhmann HJ, Kirischuk S. Glutamatergic system controls synchronization of spontaneous neuronal activity in the murine neonatal entorhinal cortex. Pflugers Arch 2014; 467:1565-1575. [PMID: 25163767 DOI: 10.1007/s00424-014-1600-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/16/2014] [Accepted: 08/20/2014] [Indexed: 12/21/2022]
Abstract
Synchronized spontaneous neuronal activity is a characteristic feature of the developing brain. Rhythmic network discharges in the neonatal medial entorhinal cortex (mEC) in vitro depend on activation of ionotropic glutamate receptors, but spontaneously active neurons are required for their initiation. Field potential recordings revealed synchronized neuronal activity in the mEC in vivo developmentally earlier than in vitro. We suggested that not only ionotropic receptors, but also other components of the glutamatergic system modulate neuronal activity in the mEC. Ca(2+) imaging was used to record neuronal activity in neonatal murine brain slices. Two types of spontaneous events were distinguished: global synchronous discharges (synchronous activity) and asynchronously (not synchronized with global discharges) active cells (asynchronous activity). AMPA receptor blockade strongly reduced the frequency of synchronous discharges, while NMDA receptor inhibition was less effective. AMPA and NMDA receptor blockade or activation of group 2/3 metabotropic glutamate receptors (mGluR2/3) completely suppressed synchronous discharges and increased the number of active cells. Blockade of glutamate transporters with DL-TBOA led to NMDA receptor-mediated hyper-synchronization of neuronal activity. Inhibition of NMDA receptors in the presence of DL-TBOA failed to restore synchronous discharges. The latter were partially reestablished only after blockade of mGluR2/3. We conclude that the glutamatergic system can influence neuronal activity via different receptors/mechanisms. As both NMDA and mGluR2/3 receptors have a high affinity for glutamate, changes in extracellular glutamate levels resulting for instance from glutamate transporter malfunction can balance neuronal activity in the mEC, affecting in turn synapse and network formation.
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Affiliation(s)
- Petr Unichenko
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128, Mainz, Germany
| | - Jeng-Wei Yang
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128, Mainz, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128, Mainz, Germany.
| | - Sergei Kirischuk
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128, Mainz, Germany
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43
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Buetfering C, Allen K, Monyer H. Parvalbumin interneurons provide grid cell-driven recurrent inhibition in the medial entorhinal cortex. Nat Neurosci 2014; 17:710-8. [PMID: 24705183 DOI: 10.1038/nn.3696] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 03/11/2014] [Indexed: 11/09/2022]
Abstract
Grid cells in the medial entorhinal cortex (MEC) generate metric spatial representations. Recent attractor-network models suggest an essential role for GABAergic interneurons in the emergence of the grid-cell firing pattern through recurrent inhibition dependent on grid-cell phase. To test this hypothesis, we studied identified parvalbumin-expressing (PV(+)) interneurons that are the most likely candidate for providing this recurrent inhibition onto grid cells. Using optogenetics and tetrode recordings in mice, we found that PV(+) interneurons exhibited high firing rates, low spatial sparsity and no spatial periodicity. PV(+) interneurons inhibited all functionally defined cell types in the MEC and were in turn recruited preferentially by grid cells. To our surprise, we found that individual PV(+) interneurons received input from grid cells with various phases, which most likely accounts for the broadly tuned spatial firing activity of PV(+) interneurons. Our data argue against the notion that PV(+) interneurons provide phase-dependent recurrent inhibition and challenge recent attractor-network models of grid cells.
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Affiliation(s)
- Christina Buetfering
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Kevin Allen
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Hannah Monyer
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
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44
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Castro L, Aguiar P. A feedforward model for the formation of a grid field where spatial information is provided solely from place cells. Biol Cybern 2014; 108:133-143. [PMID: 24577877 DOI: 10.1007/s00422-013-0581-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 12/20/2013] [Indexed: 06/03/2023]
Abstract
Grid cells (GCs) in the medial entorhinal cortex (mEC) have the property of having their firing activity spatially tuned to a regular triangular lattice. Several theoretical models for grid field formation have been proposed, but most assume that place cells (PCs) are a product of the grid cell system. There is, however, an alternative possibility that is supported by various strands of experimental data. Here we present a novel model for the emergence of gridlike firing patterns that stands on two key hypotheses: (1) spatial information in GCs is provided from PC activity and (2) grid fields result from a combined synaptic plasticity mechanism involving inhibitory and excitatory neurons mediating the connections between PCs and GCs. Depending on the spatial location, each PC can contribute with excitatory or inhibitory inputs to GC activity. The nature and magnitude of the PC input is a function of the distance to the place field center, which is inferred from rate decoding. A biologically plausible learning rule drives the evolution of the connection strengths from PCs to a GC. In this model, PCs compete for GC activation, and the plasticity rule favors efficient packing of the space representation. This leads to gridlike firing patterns. In a new environment, GCs continuously recruit new PCs to cover the entire space. The model described here makes important predictions and can represent the feedforward connections from hippocampus CA1 to deeper mEC layers.
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Affiliation(s)
- Luísa Castro
- Departamento de Matemática, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
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45
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Abstract
Episodic memory requires associations of temporally discontiguous events. In the entorhinal-hippocampal network, temporal associations are driven by a direct pathway from layer III of the medial entorhinal cortex (MECIII) to the hippocampal CA1 region. However, the identification of neural circuits that regulate this association has remained unknown. In layer II of entorhinal cortex (ECII), we report clusters of excitatory neurons called island cells, which appear in a curvilinear matrix of bulblike structures, directly project to CA1, and activate interneurons that target the distal dendrites of CA1 pyramidal neurons. Island cells suppress the excitatory MECIII input through the feed-forward inhibition to control the strength and duration of temporal association in trace fear memory. Together, the two EC inputs compose a control circuit for temporal association memory.
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Affiliation(s)
- Takashi Kitamura
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A
| | - Michele Pignatelli
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A
| | - Junghyup Suh
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A
| | - Keigo Kohara
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A
| | - Atsushi Yoshiki
- RIKEN BioResource Center, 3-1-1 Koyadai, Ibaraki 305-0074, Japan
| | - Kuniya Abe
- RIKEN BioResource Center, 3-1-1 Koyadai, Ibaraki 305-0074, Japan
| | - Susumu Tonegawa
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A
- Howard Hughes Medical Institute at MIT, Cambridge, MA 02139, U.S.A
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46
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Xiong J, He C, Li C, Tan G, Li J, Yu Z, Hu Z, Chen F. Changes of dendritic spine density and morphology in the superficial layers of the medial entorhinal cortex induced by extremely low-frequency magnetic field exposure. PLoS One 2013; 8:e83561. [PMID: 24376717 PMCID: PMC3869808 DOI: 10.1371/journal.pone.0083561] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 11/09/2013] [Indexed: 01/20/2023] Open
Abstract
In the present study, we investigated the effects of chronic exposure (14 and 28 days) to a 0.5 mT 50 Hz extremely low-frequency magnetic field (ELM) on the dendritic spine density and shape in the superficial layers of the medial entorhinal cortex (MEC). We performed Golgi staining to reveal the dendritic spines of the principal neurons in rats. The results showed that ELM exposure induced a decrease in the spine density in the dendrites of stellate neurons and the basal dendrites of pyramidal neurons at both 14 days and 28 days, which was largely due to the loss of the thin and branched spines. The alteration in the density of mushroom and stubby spines post ELM exposure was cell-type specific. For the stellate neurons, ELM exposure slightly increased the density of stubby spines at 28 days, while it did not affect the density of mushroom spines at the same time. In the basal dendrites of pyramidal neurons, we observed a significant decrease in the mushroom spine density only at the later time point post ELM exposure, while the stubby spine density was reduced at 14 days and partially restored at 28 days post ELM exposure. ELM exposure-induced reduction in the spine density in the apical dendrites of pyramidal neurons was only observed at 28 days, reflecting the distinct vulnerability of spines in the apical and basal dendrites. Considering the changes in spine number and shape are involved in synaptic plasticity and the MEC is a part of neural network that is closely related to learning and memory, these findings may be helpful for explaining the ELM exposure-induced impairment in cognitive functions.
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Affiliation(s)
- Jiaxiang Xiong
- Department of Physiology, Third Military Medical University, Chongqing, PR China
| | - Chao He
- Department of Physiology, Third Military Medical University, Chongqing, PR China
| | - Chao Li
- Department of Physiology, Third Military Medical University, Chongqing, PR China
| | - Gang Tan
- Department of Physiology, Third Military Medical University, Chongqing, PR China
| | - Jingcheng Li
- Department of Physiology, Third Military Medical University, Chongqing, PR China
| | - Zhengping Yu
- Department of Occupational Health, Third Military Medical University, Chongqing, PR China
| | - Zhian Hu
- Department of Physiology, Third Military Medical University, Chongqing, PR China
- * E-mail: (ZH); (FC)
| | - Fang Chen
- Department of Physiology, Third Military Medical University, Chongqing, PR China
- * E-mail: (ZH); (FC)
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Pilly PK, Grossberg S. Spiking neurons in a hierarchical self-organizing map model can learn to develop spatial and temporal properties of entorhinal grid cells and hippocampal place cells. PLoS One 2013; 8:e60599. [PMID: 23577130 PMCID: PMC3618326 DOI: 10.1371/journal.pone.0060599] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 02/28/2013] [Indexed: 11/30/2022] Open
Abstract
Medial entorhinal grid cells and hippocampal place cells provide neural correlates of spatial representation in the brain. A place cell typically fires whenever an animal is present in one or more spatial regions, or places, of an environment. A grid cell typically fires in multiple spatial regions that form a regular hexagonal grid structure extending throughout the environment. Different grid and place cells prefer spatially offset regions, with their firing fields increasing in size along the dorsoventral axes of the medial entorhinal cortex and hippocampus. The spacing between neighboring fields for a grid cell also increases along the dorsoventral axis. This article presents a neural model whose spiking neurons operate in a hierarchy of self-organizing maps, each obeying the same laws. This spiking GridPlaceMap model simulates how grid cells and place cells may develop. It responds to realistic rat navigational trajectories by learning grid cells with hexagonal grid firing fields of multiple spatial scales and place cells with one or more firing fields that match neurophysiological data about these cells and their development in juvenile rats. The place cells represent much larger spaces than the grid cells, which enable them to support navigational behaviors. Both self-organizing maps amplify and learn to categorize the most frequent and energetic co-occurrences of their inputs. The current results build upon a previous rate-based model of grid and place cell learning, and thus illustrate a general method for converting rate-based adaptive neural models, without the loss of any of their analog properties, into models whose cells obey spiking dynamics. New properties of the spiking GridPlaceMap model include the appearance of theta band modulation. The spiking model also opens a path for implementation in brain-emulating nanochips comprised of networks of noisy spiking neurons with multiple-level adaptive weights for controlling autonomous adaptive robots capable of spatial navigation.
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Affiliation(s)
- Praveen K. Pilly
- Center for Adaptive Systems, Center for Computational Neuroscience and Neural Technology, Boston University, Boston, Massachusetts, United States of America
| | - Stephen Grossberg
- Center for Adaptive Systems, Center for Computational Neuroscience and Neural Technology, Department of Mathematics, Boston University, Boston, Massachusetts, United States of America
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Jain S, Yoon SY, Leung L, Knoferle J, Huang Y. Cellular source-specific effects of apolipoprotein (apo) E4 on dendrite arborization and dendritic spine development. PLoS One 2013; 8:e59478. [PMID: 23527202 PMCID: PMC3602301 DOI: 10.1371/journal.pone.0059478] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Accepted: 02/14/2013] [Indexed: 01/12/2023] Open
Abstract
Apolipoprotein (apo) E4 is the leading genetic risk factor for Alzheimer’s disease (AD), and it has a gene dose-dependent effect on the risk and age of onset of AD. Although apoE4 is primarily produced by astrocytes in the brain, neurons can also produce apoE4 under stress conditions. ApoE4 is known to inhibit neurite outgrowth and spine development in vitro and in vivo, but the potential influence of apoE4’s cellular source on dendritic arborization and spine development has not yet been investigated. In this study, we report impairments in dendritic arborization and a loss of spines, especially thin (learning) and mushroom (memory) spines, in the hippocampus and entorhinal cortex of 19–21-month-old female neuron-specific-enolase (NSE)-apoE4 and apoE4-knockin (KI) mice compared to their respective apoE3-expressing counterparts. In general, NSE-apoE4 mice had more severe and widespread deficits in dendritic arborization as well as spine density and morphology than apoE4-KI mice. The loss of dendritic spines, especially mushroom spines, occurred in NSE-apoE4 mice as early as 7–8 months of age. In contrast, glial fibrillary acidic protein (GFAP)-apoE4 mice, which express apoE4 solely in astrocytes, did not have impairments in their dendrite arborization or spine density and morphology compared to GFAP-apoE3 mice at both ages. These results indicate that the effects of apoE4 on dendrite arborization, spine density, and spine morphology depend critically on its cellular source, with neuronal apoE4 having more detrimental effects than astrocytic apoE4.
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Affiliation(s)
- Sachi Jain
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, California, United States of America
| | - Seo Yeon Yoon
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Laura Leung
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, California, United States of America
| | - Johanna Knoferle
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, California, United States of America
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Gladstone Institute of Cardiovascular Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, California, United States of America
- Department of Pathology, University of California San Francisco, California, United States of America
- * E-mail:
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Abstract
The entorhinal cortex is a brain area with multiple reciprocal connections to the hippocampus, amygdala, perirhinal cortex, olfactory bulb and piriform cortex. As such, it is thought to play a large role in the olfactory memory process. The present study is the first to compare lateral entorhinal and anterior piriform cortex odor-evoked single-unit and local field potential activity in mouse. Recordings were made in urethane-anesthetized mice that were administered a range of three pure odors and three overlapping odor mixtures. Results show that spontaneous as well as odor-evoked unit activity was lower in lateral entorhinal versus piriform cortex. In addition, units in lateral entorhinal cortex were responsive to a more restricted set of odors compared to piriform. Conversely, odor-evoked power change in local field potential activity was greater in the lateral entorhinal cortex in the theta band than in piriform. The highly odor-specific and restricted firing in lateral entorhinal cortex suggests that it may play a role in modulating odor-specific, experience- and state-dependent olfactory coding.
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Affiliation(s)
- W Xu
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research Orangeburg, NY 10962, USA.
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Grossberg S, Pilly PK. How entorhinal grid cells may learn multiple spatial scales from a dorsoventral gradient of cell response rates in a self-organizing map. PLoS Comput Biol 2012; 8:e1002648. [PMID: 23055909 PMCID: PMC3464193 DOI: 10.1371/journal.pcbi.1002648] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 06/20/2012] [Indexed: 11/19/2022] Open
Abstract
Place cells in the hippocampus of higher mammals are critical for spatial navigation. Recent modeling clarifies how this may be achieved by how grid cells in the medial entorhinal cortex (MEC) input to place cells. Grid cells exhibit hexagonal grid firing patterns across space in multiple spatial scales along the MEC dorsoventral axis. Signals from grid cells of multiple scales combine adaptively to activate place cells that represent much larger spaces than grid cells. But how do grid cells learn to fire at multiple positions that form a hexagonal grid, and with spatial scales that increase along the dorsoventral axis? In vitro recordings of medial entorhinal layer II stellate cells have revealed subthreshold membrane potential oscillations (MPOs) whose temporal periods, and time constants of excitatory postsynaptic potentials (EPSPs), both increase along this axis. Slower (faster) subthreshold MPOs and slower (faster) EPSPs correlate with larger (smaller) grid spacings and field widths. A self-organizing map neural model explains how the anatomical gradient of grid spatial scales can be learned by cells that respond more slowly along the gradient to their inputs from stripe cells of multiple scales, which perform linear velocity path integration. The model cells also exhibit MPO frequencies that covary with their response rates. The gradient in intrinsic rhythmicity is thus not compelling evidence for oscillatory interference as a mechanism of grid cell firing. A response rate gradient combined with input stripe cells that have normalized receptive fields can reproduce all known spatial and temporal properties of grid cells along the MEC dorsoventral axis. This spatial gradient mechanism is homologous to a gradient mechanism for temporal learning in the lateral entorhinal cortex and its hippocampal projections. Spatial and temporal representations may hereby arise from homologous mechanisms, thereby embodying a mechanistic “neural relativity” that may clarify how episodic memories are learned. Spatial navigation is a critical competence of all higher mammals, and place cells in the hippocampus represent the large spaces in which they navigate. Recent modeling clarifies how this may occur via interactions between grid cells in the medial entorhinal cortex (MEC) and place cells. Grid cells exhibit hexagonal grid firing patterns across space and come in multiple spatial scales that increase along the dorsoventral axis of MEC. Signals from multiple scales of grid cells combine to activate place cells that represent much larger spaces than grid cells. This article shows how a gradient of cell response rates along the dorsoventral axis enables the learning of grid cells with the observed gradient of spatial scales as an animal navigates realistic trajectories. The observed gradient of grid cell membrane potential oscillation frequencies is shown to be a direct result of the gradient of response rates. This gradient mechanism for spatial learning is homologous to a gradient mechanism for temporal learning in the lateral entorhinal cortex and its hippocampal projections, thereby clarifying why both spatial and temporal representations are found in the entorhinal-hippocampal system.
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Affiliation(s)
- Stephen Grossberg
- Center for Adaptive Systems, Graduate Program in Cognitive and Neural Systems, and Center for Computational Neuroscience and Neural Technology, Boston University, Boston, Massachusetts, United States of America.
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