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Concetti C, Viskaitis P, Grujic N, Duss SN, Privitera M, Bohacek J, Peleg-Raibstein D, Burdakov D. Exploratory Rearing Is Governed by Hypothalamic Melanin-Concentrating Hormone Neurons According to Locus Ceruleus. J Neurosci 2024; 44:e0015242024. [PMID: 38575343 PMCID: PMC11112542 DOI: 10.1523/jneurosci.0015-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 03/20/2024] [Accepted: 03/25/2024] [Indexed: 04/06/2024] Open
Abstract
Information seeking, such as standing on tiptoes to look around in humans, is observed across animals and helps survival. Its rodent analog-unsupported rearing on hind legs-was a classic model in deciphering neural signals of cognition and is of intense renewed interest in preclinical modeling of neuropsychiatric states. Neural signals and circuits controlling this dedicated decision to seek information remain largely unknown. While studying subsecond timing of spontaneous behavioral acts and activity of melanin-concentrating hormone (MCH) neurons (MNs) in behaving male and female mice, we observed large MN activity spikes that aligned to unsupported rears. Complementary causal, loss and gain of function, analyses revealed specific control of rear frequency and duration by MNs and MCHR1 receptors. Activity in a key stress center of the brain-the locus ceruleus noradrenaline cells-rapidly inhibited MNs and required functional MCH receptors for its endogenous modulation of rearing. By defining a neural module that both tracks and controls rearing, these findings may facilitate further insights into biology of information seeking.
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Affiliation(s)
- Cristina Concetti
- Department of Health Sciences and Technology, Neuroscience Center Zürich (ZNZ), Swiss Federal Institute of Technology (ETH Zürich), Zürich 8092, Switzerland
| | - Paulius Viskaitis
- Department of Health Sciences and Technology, Neuroscience Center Zürich (ZNZ), Swiss Federal Institute of Technology (ETH Zürich), Zürich 8092, Switzerland
| | - Nikola Grujic
- Department of Health Sciences and Technology, Neuroscience Center Zürich (ZNZ), Swiss Federal Institute of Technology (ETH Zürich), Zürich 8092, Switzerland
| | - Sian N Duss
- Department of Health Sciences and Technology, Neuroscience Center Zürich (ZNZ), Swiss Federal Institute of Technology (ETH Zürich), Zürich 8092, Switzerland
| | - Mattia Privitera
- Department of Health Sciences and Technology, Neuroscience Center Zürich (ZNZ), Swiss Federal Institute of Technology (ETH Zürich), Zürich 8092, Switzerland
| | - Johannes Bohacek
- Department of Health Sciences and Technology, Neuroscience Center Zürich (ZNZ), Swiss Federal Institute of Technology (ETH Zürich), Zürich 8092, Switzerland
| | - Daria Peleg-Raibstein
- Department of Health Sciences and Technology, Neuroscience Center Zürich (ZNZ), Swiss Federal Institute of Technology (ETH Zürich), Zürich 8092, Switzerland
| | - Denis Burdakov
- Department of Health Sciences and Technology, Neuroscience Center Zürich (ZNZ), Swiss Federal Institute of Technology (ETH Zürich), Zürich 8092, Switzerland
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2
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Varga V, Petersen P, Zutshi I, Huszar R, Zhang Y, Buzsáki G. Working memory features are embedded in hippocampal place fields. Cell Rep 2024; 43:113807. [PMID: 38401118 PMCID: PMC11044127 DOI: 10.1016/j.celrep.2024.113807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/13/2023] [Accepted: 01/31/2024] [Indexed: 02/26/2024] Open
Abstract
Hippocampal principal neurons display both spatial tuning properties and memory features. Whether this distinction corresponds to separate neuron types or a context-dependent continuum has been debated. We report here that the task-context ("splitter") feature is highly variable along both trial and spatial position axes. Neurons acquire or lose splitter features across trials even when place field features remain unaltered. Multiple place fields of the same neuron can individually encode both past or future run trajectories, implying that splitter fields are under the control of assembly activity. Place fields can be differentiated into subfields by the behavioral choice of the animal, and splitting within subfields evolves across trials. Interneurons also differentiate choices by integrating inputs from pyramidal cells. Finally, bilateral optogenetic inactivation of the medial entorhinal cortex reversibly decreases the fraction of splitter fields. Our findings suggest that place or splitter features are different manifestations of the same hippocampal computation.
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Affiliation(s)
- Viktor Varga
- Neuroscience Institute, Langone Health, New York University, New York, NY, USA; Subcortical Modulation Research Group, Institute of Experimental Medicine - Hungarian Research Network, Budapest, Hungary
| | - Peter Petersen
- Neuroscience Institute, Langone Health, New York University, New York, NY, USA; Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Ipshita Zutshi
- Neuroscience Institute, Langone Health, New York University, New York, NY, USA
| | - Roman Huszar
- Neuroscience Institute, Langone Health, New York University, New York, NY, USA
| | - Yiyao Zhang
- Neuroscience Institute, Langone Health, New York University, New York, NY, USA
| | - György Buzsáki
- Neuroscience Institute, Langone Health, New York University, New York, NY, USA; Department of Neuroscience and Physiology, Langone Health, New York University, New York, NY, USA; Department of Neurology, Langone Health, New York University, New York, NY, USA.
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3
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O'Connor M, Qiao H, Odamah K, Cerdeira PC, Man HY. Heterozygous Nexmif female mice demonstrate mosaic NEXMIF expression, autism-like behaviors, and abnormalities in dendritic arborization and synaptogenesis. Heliyon 2024; 10:e24703. [PMID: 38322873 PMCID: PMC10844029 DOI: 10.1016/j.heliyon.2024.e24703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 11/28/2023] [Accepted: 01/12/2024] [Indexed: 02/08/2024] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder with a strong genetic basis. ASDs are commonly characterized by impairments in language, restrictive and repetitive behaviors, and deficits in social interactions. Although ASD is a highly heterogeneous disease with many different genes implicated in its etiology, many ASD-associated genes converge on common cellular defects, such as aberrant neuronal morphology and synapse dysregulation. Our previous work revealed that, in mice, complete loss of the ASD-associated X-linked gene NEXMIF results in a reduction in dendritic complexity, a decrease in spine and synapse density, altered synaptic transmission, and ASD-like behaviors. Interestingly, human females of NEXMIF haploinsufficiency have recently been reported to demonstrate autistic features; however, the cellular and molecular basis for this haploinsufficiency-caused ASD remains unclear. Here we report that in the brains of Nexmif± female mice, NEXMIF shows a mosaic pattern in its expression in neurons. Heterozygous female mice demonstrate behavioral impairments similar to those of knockout male mice. In the mosaic mixture of neurons from Nexmif± mice, cells that lack NEXMIF have impairments in dendritic arborization and spine development. Remarkably, the NEXMIF-expressing neurons from Nexmif± mice also demonstrate similar defects in dendritic growth and spine formation. These findings establish a novel mouse model of NEXMIF haploinsufficiency and provide new insights into the pathogenesis of NEXMIF-dependent ASD.
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Affiliation(s)
- Margaret O'Connor
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - Hui Qiao
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - KathrynAnn Odamah
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | | | - Heng-Ye Man
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
- Department of Pharmacology, Physiology & Biophysics, Boston University School of Medicine, 72 East Concord St., Boston, MA 02118, USA
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Ave, Boston, MA 02215, USA
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4
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Shan X, Contreras MP, Sawangjit A, Dimitrov S, Born J, Inostroza M. Rearing is critical for forming spatial representations in pre-weanling rats. Behav Brain Res 2023; 452:114545. [PMID: 37321311 DOI: 10.1016/j.bbr.2023.114545] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/24/2023] [Accepted: 06/13/2023] [Indexed: 06/17/2023]
Abstract
Rearing, i.e., standing on the hind limbs in an upright posture, is part of a rat's innate exploratory motor program. Here, we examined in developing rats whether rearing is critical for the pup's capability to form spatial representations based on distal environmental cues. Pups (male) were tested at PD18, i.e., the first day they typically exhibit stable rearing, on a spatial habituation paradigm comprising a Familiarization session (with the pup exposed to an arena with a specific configuration of distal cues) followed, 3 h later, by a Test session where the pups were either re-exposed to the identical distal cue configuration (NoChange) or a changed configuration (DistalChange). In Experiment 1, rearing activity (rearing events, duration) decreased from Familiarization to Test in the NoChange pups but, remained elevated in the DistalChange group indicating that these pups recognized the distal novelty. Recognition of distal novelty was associated with increased c-Fos expression in hippocampal and medial prefrontal cortex (mPFC) areas, compared with NoChange pups. Analysis of GAD67+ cells suggested a parallel increase in excitation and inhibition specifically in prelimbic mPFC networks in response to distal cue changes. In Experiment 2, the pups were mechanically prevented from rearing while still seeing the distal cues during Familiarization. Rearing activity in the Test session of these pups did not differ between groups that were or were not exposed to a changed distal cue configuration at Test. The findings evidence a critical role of rearing for the emergence of allocentric representations integrating distal space during early development.
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Affiliation(s)
- Xia Shan
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Graduate School of Neural & Behavioural Science, International Max Planck Research School, Tübingen, Germany
| | - María Paz Contreras
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Graduate School of Neural & Behavioural Science, International Max Planck Research School, Tübingen, Germany
| | - Anuck Sawangjit
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Stoyan Dimitrov
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD), Institute for Diabetes Research & Metabolic Diseases of the Helmholtz Center Munich at the University Tübingen (IDM), Germany; Werner Reichert Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany; German Center for Mental Health (DZPG), Germany.
| | - Marion Inostroza
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
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Inyang D, Saumtally T, Nnadi CN, Devi S, So PW. A Systematic Review of the Effects of Capsaicin on Alzheimer's Disease. Int J Mol Sci 2023; 24:10176. [PMID: 37373321 DOI: 10.3390/ijms241210176] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/11/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
Alzheimer's Disease (AD) is a progressive neurodegenerative disorder characterised by cognitive impairment, and amyloid-β plaques and neurofibrillary tau tangles at neuropathology. Capsaicin is a spicy-tasting compound found in chili peppers, with anti-inflammatory, antioxidant, and possible neuroprotective properties. Capsaicin intake has been associated with greater cognitive function in humans, and attenuating aberrant tau hyperphosphorylation in a rat model of AD. This systematic review discusses the potential of capsaicin in improving AD pathology and symptoms. A systematic analysis was conducted on the effect of capsaicin on AD-associated molecular changes, cognitive and behaviour resulting in 11 studies employing rodents and/or cell cultures, which were appraised with the Cochrane Risk of Bias tool. Ten studies showed capsaicin attenuated tau deposition, apoptosis, and synaptic dysfunction; was only weakly effective on oxidative stress; and had conflicting effects on amyloid processing. Eight studies demonstrated improved spatial and working memory, learning, and emotional behaviours in rodents following capsaicin treatment. Overall, capsaicin showed promise in improving AD-associated molecular, cognitive, and behavioural changes in cellular and animal models, and further investigations are recommended to test the readily available bioactive, capsaicin, to treat AD.
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Affiliation(s)
- Deborah Inyang
- Basic and Clinical Neuroscience Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, UK
| | - Tasneem Saumtally
- Basic and Clinical Neuroscience Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, UK
| | - Chinelo Nonyerem Nnadi
- Basic and Clinical Neuroscience Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, UK
| | - Sharmila Devi
- Basic and Clinical Neuroscience Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, UK
| | - Po-Wah So
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, UK
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6
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Layfield D, Sidell N, Blankenberger K, Newman EL. Hippocampal inactivation during rearing on hind legs impairs spatial memory. Sci Rep 2023; 13:6136. [PMID: 37061540 PMCID: PMC10105745 DOI: 10.1038/s41598-023-33209-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 04/09/2023] [Indexed: 04/17/2023] Open
Abstract
Spatial memory requires an intact hippocampus. Hippocampal function during epochs of locomotion and quiet rest (e.g., grooming and reward consumption) has been the target of extensive study. However, during navigation rats frequently rear up onto their hind legs, and the importance of hippocampal activity during these periods of attentive sampling for spatial memory is unknown. To address this, we tested the necessity of dorsal hippocampal activity during rearing epochs in the study phase of a delayed win-shift task for memory performance in the subsequent test phase. Hippocampal activity was manipulated with closed-loop, bilateral, optogenetic inactivation. Spatial memory accuracy was significantly and selectively reduced when the dorsal hippocampus was inactivated during rearing epochs at encoding. These data show that hippocampal activity during periods of rearing can be important for spatial memory, revealing a novel link between hippocampal function during epochs of rearing and spatial memory.
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Affiliation(s)
- Dylan Layfield
- Program in Neuroscience, Indiana University, 1101 E 10th St, Bloomington, IN, 47405, USA.
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10th St, Bloomington, IN, 47405, USA.
| | - Nathan Sidell
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10th St, Bloomington, IN, 47405, USA
| | - Kevin Blankenberger
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10th St, Bloomington, IN, 47405, USA
| | - Ehren Lee Newman
- Program in Neuroscience, Indiana University, 1101 E 10th St, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10th St, Bloomington, IN, 47405, USA
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7
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Kitchigina V, Shubina L. Oscillations in the dentate gyrus as a tool for the performance of the hippocampal functions: Healthy and epileptic brain. Prog Neuropsychopharmacol Biol Psychiatry 2023; 125:110759. [PMID: 37003419 DOI: 10.1016/j.pnpbp.2023.110759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 03/17/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The dentate gyrus (DG) is part of the hippocampal formation and is essential for important cognitive processes such as navigation and memory. The oscillatory activity of the DG network is believed to play a critical role in cognition. DG circuits generate theta, beta, and gamma rhythms, which participate in the specific information processing performed by DG neurons. In the temporal lobe epilepsy (TLE), cognitive abilities are impaired, which may be due to drastic alterations in the DG structure and network activity during epileptogenesis. The theta rhythm and theta coherence are especially vulnerable in dentate circuits; disturbances in DG theta oscillations and their coherence may be responsible for general cognitive impairments observed during epileptogenesis. Some researchers suggested that the vulnerability of DG mossy cells is a key factor in the genesis of TLE, but others did not support this hypothesis. The aim of the review is not only to present the current state of the art in this field of research but to help pave the way for future investigations by highlighting the gaps in our knowledge to completely appreciate the role of DG rhythms in brain functions. Disturbances in oscillatory activity of the DG during TLE development may be a diagnostic marker in the treatment of this disease.
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Affiliation(s)
- Valentina Kitchigina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia.
| | - Liubov Shubina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
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8
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Hines M, Poulter S, Douchamps V, Pibiri F, McGregor A, Lever C. Frequency matters: how changes in hippocampal theta frequency can influence temporal coding, anxiety-reduction, and memory. Front Syst Neurosci 2023; 16:998116. [PMID: 36817946 PMCID: PMC9936826 DOI: 10.3389/fnsys.2022.998116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 12/30/2022] [Indexed: 02/05/2023] Open
Abstract
Hippocampal theta frequency is a somewhat neglected topic relative to theta power, phase, coherence, and cross-frequency coupling. Accordingly, here we review and present new data on variation in hippocampal theta frequency, focusing on functional associations (temporal coding, anxiety reduction, learning, and memory). Taking the rodent hippocampal theta frequency to running-speed relationship as a model, we identify two doubly-dissociable frequency components: (a) the slope component of the theta frequency-to-stimulus-rate relationship ("theta slope"); and (b) its y-intercept frequency ("theta intercept"). We identify three tonic determinants of hippocampal theta frequency. (1) Hotter temperatures increase theta frequency, potentially consistent with time intervals being judged as shorter when hot. Initial evidence suggests this occurs via the "theta slope" component. (2) Anxiolytic drugs with widely-different post-synaptic and pre-synaptic primary targets share the effect of reducing the "theta intercept" component, supporting notions of a final common pathway in anxiety reduction involving the hippocampus. (3) Novelty reliably decreases, and familiarity increases, theta frequency, acting upon the "theta slope" component. The reliability of this latter finding, and the special status of novelty for learning, prompts us to propose a Novelty Elicits Slowing of Theta frequency (NEST) hypothesis, involving the following elements: (1) Theta frequency slowing in the hippocampal formation is a generalised response to novelty of different types and modalities; (2) Novelty-elicited theta slowing is a hippocampal-formation-wide adaptive response functioning to accommodate the additional need for learning entailed by novelty; (3) Lengthening the theta cycle enhances associativity; (4) Even part-cycle lengthening may boost associativity; and (5) Artificial theta stimulation aimed at enhancing learning should employ low-end theta frequencies.
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9
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Depression-Associated Negr1 Gene-Deficiency Induces Alterations in the Monoaminergic Neurotransmission Enhancing Time-Dependent Sensitization to Amphetamine in Male Mice. Brain Sci 2022; 12:brainsci12121696. [PMID: 36552158 PMCID: PMC9776224 DOI: 10.3390/brainsci12121696] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
In GWAS studies, the neural adhesion molecule encoding the neuronal growth regulator 1 (NEGR1) gene has been consistently linked with both depression and obesity. Although the linkage between NEGR1 and depression is the strongest, evidence also suggests the involvement of NEGR1 in a wide spectrum of psychiatric conditions. Here we show the expression of NEGR1 both in tyrosine- and tryptophan hydroxylase-positive cells. Negr1-/- mice show a time-dependent increase in behavioral sensitization to amphetamine associated with increased dopamine release in both the dorsal and ventral striatum. Upregulation of transcripts encoding dopamine and serotonin transporters and higher levels of several monoamines and their metabolites was evident in distinct brain areas of Negr1-/- mice. Chronic (23 days) escitalopram-induced reduction of serotonin and dopamine turnover is enhanced in Negr1-/- mice, and escitalopram rescued reduced weight of hippocampi in Negr1-/- mice. The current study is the first to show alterations in the brain monoaminergic systems in Negr1-deficient mice, suggesting that monoaminergic neural circuits contribute to both depressive and obesity-related phenotypes linked to the human NEGR1 gene.
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10
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Griffith TA, Russell JS, Naghipour S, Helman TJ, Peart JN, Stapelberg NJ, Headrick JP, Du Toit EF. Behavioural disruption in diabetic mice: Neurobiological correlates and influences of dietary α-linolenic acid. Life Sci 2022; 311:121137. [DOI: 10.1016/j.lfs.2022.121137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 10/17/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022]
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11
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Rukundo P, Feng T, Pham V, Pieraut S. Moderate effect of early-life experience on dentate gyrus function. Mol Brain 2022; 15:92. [PMID: 36411441 PMCID: PMC9677655 DOI: 10.1186/s13041-022-00980-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/06/2022] [Indexed: 11/22/2022] Open
Abstract
The development, maturation, and plasticity of neural circuits are strongly influenced by experience and the interaction of an individual with their environment can have a long-lasting effect on cognitive function. Using an enriched environment (EE) paradigm, we have recently demonstrated that enhancing social, physical, and sensory activity during the pre-weaning time in mice led to an increase of inhibitory and excitatory synapses in the dentate gyrus (DG) of the hippocampus. The structural plasticity induced by experience may affect information processing in the circuit. The DG performs pattern separation, a computation that enables the encoding of very similar and overlapping inputs into dissimilar outputs. In the presented study, we have tested the hypothesis that an EE in juvenile mice will affect DG's functions that are relevant for pattern separation: the decorrelation of the inputs from the entorhinal cortex (EC) and the recruitment of the principal excitatory granule cell (GC) during behavior. First, using a novel slice electrophysiology protocol, we found that the transformation of the incoming signal from the EC afferents by individual GC is moderately affected by EE. We further show that EE does not affect behaviorally induced recruitment of principal excitatory GC. Lastly, using the novel object recognition task, a hippocampus-dependent memory test, we show that the ontogeny of this discrimination task was similar among the EE mice and the controls. Taken together, our work demonstrates that pre-weaning enrichment moderately affects DG function.
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Affiliation(s)
- Pacifique Rukundo
- grid.266818.30000 0004 1936 914XDepartment of Biology, University of Nevada, Reno, NV 89557 USA
| | - Ting Feng
- grid.266818.30000 0004 1936 914XDepartment of Biology, University of Nevada, Reno, NV 89557 USA
| | - Vincent Pham
- grid.266818.30000 0004 1936 914XDepartment of Biology, University of Nevada, Reno, NV 89557 USA
| | - Simon Pieraut
- grid.266818.30000 0004 1936 914XDepartment of Biology, University of Nevada, Reno, NV 89557 USA
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12
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Loh MK, Ferrara NC, Torres JM, Rosenkranz JA. Medial orbitofrontal cortex and nucleus accumbens mediation in risk assessment behaviors in adolescents and adults. Neuropsychopharmacology 2022; 47:1808-1815. [PMID: 35039643 PMCID: PMC9372086 DOI: 10.1038/s41386-022-01273-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 01/05/2022] [Accepted: 01/07/2022] [Indexed: 11/09/2022]
Abstract
Risk assessment behaviors are necessary for gathering risk information and guiding decision-making. Risky decision-making heightens during adolescence, possibly as a result of low risk awareness and an increase in sensitivity to reward-associated cues and experiences. Higher adolescent engagement in high-risk behaviors may be, in part, due to developing circuits that contribute to risk assessment behaviors. Nucleus accumbens (NAc) activity is linked to risky decision-making and receives inputs carrying sensory and emotional information. Namely, the medial orbitofrontal cortex (MO) contributes to behavior guided by reward probability and sends direct projections to the NAc (MO→NAc), which may permit risk assessment in a mature circuit. Here, we evaluated risk assessment behaviors in adult and adolescent rats during elevated plus maze (EPM) exploration, including stretch and attend postures, head dips, and rears. We found that adolescents exhibited fewer EPM risk assessment behaviors than adults. We also quantified MO→NAc projections using a fluorescent anterograde tracer, Fluoro-Ruby, in both age groups. Labeled MO→NAc pathways exhibited greater total fluorescence in adults than in adolescents, indicating MO→NAc fibers increase over development. Using a disconnection approach to measure the contribution of the MO-NAc pathway in adults, we found that ipsilateral inactivation of the MO-NAc did not alter risk assessment behavior; however, MO-NAc disconnection reduced the number of stretch-and-attend postures. Together, this work suggests that the development of MO-NAc pathways can contribute to age-dependent differences in risk assessment.
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Affiliation(s)
- Maxine K Loh
- Department of Foundational Sciences and Humanities, Cellular and Molecular Pharmacology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA.
- Center for Neurobiology of Stress Resilience and Psychiatric Disorders, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA.
| | - Nicole C Ferrara
- Department of Foundational Sciences and Humanities, Cellular and Molecular Pharmacology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
- Center for Neurobiology of Stress Resilience and Psychiatric Disorders, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Jocelyn M Torres
- Department of Foundational Sciences and Humanities, Cellular and Molecular Pharmacology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
- Center for Neurobiology of Stress Resilience and Psychiatric Disorders, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - J Amiel Rosenkranz
- Department of Foundational Sciences and Humanities, Cellular and Molecular Pharmacology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
- Center for Neurobiology of Stress Resilience and Psychiatric Disorders, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
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13
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Kopsick JD, Hartzell K, Lazaro H, Nambiar P, Hasselmo ME, Dannenberg H. Temporal dynamics of cholinergic activity in the septo-hippocampal system. Front Neural Circuits 2022; 16:957441. [PMID: 36092276 PMCID: PMC9452968 DOI: 10.3389/fncir.2022.957441] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Cholinergic projection neurons in the medial septum and diagonal band of Broca are the major source of cholinergic modulation of hippocampal circuit functions that support neural coding of location and running speed. Changes in cholinergic modulation are known to correlate with changes in brain states, cognitive functions, and behavior. However, whether cholinergic modulation can change fast enough to serve as a potential speed signal in hippocampal and parahippocampal cortices and whether the temporal dynamics in such a signal depend on the presence of visual cues remain unknown. In this study, we use a fiber-photometric approach to quantify the temporal dynamics of cholinergic activity in freely moving mice as a function of the animal's movement speed and visual cues. We show that the population activity of cholinergic neurons in the medial septum and diagonal band of Broca changes fast enough to be aligned well with changes in the animal's running speed and is strongly and linearly correlated to the logarithm of the animal's running speed. Intriguingly, the cholinergic modulation remains strongly and linearly correlated to the speed of the animal's neck movements during periods of stationary activity. Furthermore, we show that cholinergic modulation is unaltered during darkness. Lastly, we identify rearing, a stereotypic behavior where the mouse stands on its hindlimbs to scan the environment from an elevated perspective, is associated with higher cholinergic activity than expected from neck movements on the horizontal plane alone. Taken together, these data show that temporal dynamics in the cholinergic modulation of hippocampal circuits are fast enough to provide a potential running speed signal in real-time. Moreover, the data show that cholinergic modulation is primarily a function of the logarithm of the animal's movement speed, both during locomotion and during stationary activity, with no significant interaction with visual inputs. These data advance our understanding of temporal dynamics in cholinergic modulation of hippocampal circuits and their functions in the context of neural coding of location and running speed.
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Affiliation(s)
- Jeffrey D. Kopsick
- Department of Bioengineering, George Mason University, Fairfax, VA, United States,Interdisciplinary Program for Neuroscience, George Mason University, Fairfax, VA, United States
| | - Kyle Hartzell
- Department of Bioengineering, George Mason University, Fairfax, VA, United States
| | - Hallie Lazaro
- Center for Systems Neuroscience, Boston University, Boston, MA, United States,Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
| | - Pranav Nambiar
- Center for Systems Neuroscience, Boston University, Boston, MA, United States,Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
| | - Michael E. Hasselmo
- Center for Systems Neuroscience, Boston University, Boston, MA, United States,Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
| | - Holger Dannenberg
- Department of Bioengineering, George Mason University, Fairfax, VA, United States,Interdisciplinary Program for Neuroscience, George Mason University, Fairfax, VA, United States,*Correspondence: Holger Dannenberg,
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14
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Two distinct ways to form long-term object recognition memory during sleep and wakefulness. Proc Natl Acad Sci U S A 2022; 119:e2203165119. [PMID: 35969775 PMCID: PMC9407643 DOI: 10.1073/pnas.2203165119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Memory consolidation is promoted by sleep. However, there is also evidence for consolidation into long-term memory during wakefulness via processes that preferentially affect nonhippocampal representations. We compared, in rats, the effects of 2-h postencoding periods of sleep and wakefulness on the formation of long-term memory for objects and their associated environmental contexts. We employed a novel-object recognition (NOR) task, using object exploration and exploratory rearing as behavioral indicators of these memories. Remote recall testing (after 1 wk) confirmed significant long-term NOR memory under both conditions, with NOR memory after sleep predicted by the occurrence of EEG spindle-slow oscillation coupling. Rats in the sleep group decreased their exploratory rearing at recall testing, revealing successful recall of the environmental context. By contrast, rats that stayed awake after encoding showed equally high levels of rearing upon remote testing as during encoding, indicating that context memory was lost. Disruption of hippocampal function during the postencoding interval (by muscimol administration) suppressed long-term NOR memory together with context memory formation when animals slept, but enhanced NOR memory when they were awake during this interval. Testing remote recall in a context different from that during encoding impaired NOR memory in the sleep condition, while exploratory rearing was increased. By contrast, NOR memory in the wake rats was preserved and actually superior to that after sleep. Our findings indicate two distinct modes of long-term memory formation: Sleep consolidation is hippocampus dependent and implicates event-context binding, whereas wake consolidation is impaired by hippocampal activation and strengthens context-independent representations.
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15
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Green L, Tingley D, Rinzel J, Buzsáki G. Action-driven remapping of hippocampal neuronal populations in jumping rats. Proc Natl Acad Sci U S A 2022; 119:e2122141119. [PMID: 35737843 PMCID: PMC9245695 DOI: 10.1073/pnas.2122141119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 05/03/2022] [Indexed: 12/24/2022] Open
Abstract
The current dominant view of the hippocampus is that it is a navigation "device" guided by environmental inputs. Yet, a critical aspect of navigation is a sequence of planned, coordinated actions. We examined the role of action in the neuronal organization of the hippocampus by training rats to jump a gap on a linear track. Recording local field potentials and ensembles of single units in the hippocampus, we found that jumping produced a stereotypic behavior associated with consistent electrophysiological patterns, including phase reset of theta oscillations, predictable global firing-rate changes, and population vector shifts of hippocampal neurons. A subset of neurons ("jump cells") were systematically affected by the gap but only in one direction of travel. Novel place fields emerged and others were either boosted or attenuated by jumping, yet the theta spike phase versus animal position relationship remained unaltered. Thus, jumping involves an action plan for the animal to traverse the same route as without jumping, which is faithfully tracked by hippocampal neuronal activity.
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Affiliation(s)
- Laura Green
- Neuroscience Institute, Langone Medical Center, New York University, New York, NY 10016
- Center for Neural Science, New York University, New York, NY 10003
| | - David Tingley
- Neuroscience Institute, Langone Medical Center, New York University, New York, NY 10016
| | - John Rinzel
- Center for Neural Science, New York University, New York, NY 10003
- Courant Institute for Mathematical Sciences, New York University, New York, NY 10012
| | - György Buzsáki
- Neuroscience Institute, Langone Medical Center, New York University, New York, NY 10016
- Center for Neural Science, New York University, New York, NY 10003
- Department of Neurology, Langone Medical Center, New York University, New York, NY 10016
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16
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Something new and something blue: Responses to novelty in a rodent model of depression and epilepsy comorbidity. Physiol Behav 2022; 249:113778. [PMID: 35278474 DOI: 10.1016/j.physbeh.2022.113778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/27/2022] [Accepted: 03/08/2022] [Indexed: 11/20/2022]
Abstract
A bidirectional comorbidity exists between depression and epilepsy such that patients with epilepsy are at higher risk for developing depression, and vice versa. Each of these conditions individually can be complicated by behavioral effects that worsen quality of life, but less is known about these interactions within the comorbidity of depression and epilepsy. The SwLo rat has been selectively bred for depression-relevant behaviors and exhibits enhanced limbic seizure susceptibility. This study sought to characterize the effects of novelty and stress on the SwLo rodent model of this comorbidity. It was hypothesized that SwLo rats would exhibit altered responses to novelty, reflected in hyperactivity-, anxiety-, sensation seeking-, and/or compulsive behaviors, and that this would be exacerbated with stress. Compared to the SwHi rat (their depression- and epilepsy-resistant counterparts), SwLo rats showed increased entries in all areas of the Open Field Test and spent significantly more time in the light compartment of the Light-Dark Box. SwLo rats also had a significantly higher number of rearing behaviors in the inner squares of the Open Field Test, the closed arms of the Elevated Plus Maze, and both areas of the Light-Dark Box. They demonstrated increased Nestlet shredding but showed no difference in a marble burying task or in latency to consume food in a novelty suppressed feeding task. Interestingly, restraint stress showed little effect on these behaviors, despite increasing corticosterone levels. Combined, these results suggest an increase in exploratory sensation seeking and hypervigilant information-gathering behaviors in the SwLo rat that are not dependent on corticosterone levels. This shows the utility of this model for studying behavioral effects of comorbid depression and epilepsy and allows for their use in identifying underlying mechanisms or screening treatment strategies for this complex comorbidity.
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17
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Modular microcircuit organization of the presubicular head-direction map. Cell Rep 2022; 39:110684. [PMID: 35417686 DOI: 10.1016/j.celrep.2022.110684] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 02/16/2022] [Accepted: 03/24/2022] [Indexed: 11/22/2022] Open
Abstract
Our internal sense of direction is thought to rely on the activity of head-direction (HD) neurons. We find that the mouse dorsal presubiculum (PreS), a key structure in the cortical representation of HD, displays a modular "patch-matrix" organization, which is conserved across species (including human). Calbindin-positive layer 2 neurons within the "matrix" form modular recurrent microcircuits, while inputs from the anterodorsal and laterodorsal thalamic nuclei are non-overlapping and target the "patch" and "matrix" compartments, respectively. The apical dendrites of identified HD cells are largely restricted within the "matrix," pointing to a non-random sampling of patterned inputs and to a precise structure-function architecture. Optogenetic perturbation of modular recurrent microcircuits results in a drastic tonic suppression of firing only in a subpopulation of HD neurons. Altogether, our data reveal a modular microcircuit organization of the PreS HD map and point to the existence of cell-type-specific microcircuits that support the cortical HD representation.
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18
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Mysin I, Shubina L. From mechanisms to functions: The role of theta and gamma coherence in the intrahippocampal circuits. Hippocampus 2022; 32:342-358. [PMID: 35192228 DOI: 10.1002/hipo.23410] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 02/09/2022] [Accepted: 02/12/2022] [Indexed: 11/08/2022]
Abstract
Brain rhythms are essential for information processing in neuronal networks. Oscillations recorded in different brain regions can be synchronized and have a constant phase difference, that is, they can be coherent. Coherence between local field potential (LFP) signals from different brain regions may be correlated with the performance of cognitive tasks, indicating that these regions of the brain are jointly involved in the information processing. Why does coherence occur and how is it related to the information transfer between different regions of the hippocampal formation? In this article, we discuss possible mechanisms of theta and gamma coherence and its role in the hippocampus-dependent attention and memory processes, since theta and gamma rhythms are most pronounced in these processes. We review in vivo studies of interactions between different regions of the hippocampal formation in theta and gamma frequency bands. The key propositions of the review are as follows: (1) coherence emerges from synchronous postsynaptic currents in principal neurons as a result of synchronization of neuronal spike activity; (2) the synchronization of neuronal spike patterns in two regions of the hippocampal formation can be realized through induction or resonance; (3) coherence at a specific time point reflects the transfer of information between the regions of the hippocampal formation; (4) the physiological roles of theta and gamma coherence are different due to their different functions and mechanisms of generation. All hippocampal neurons are involved in theta activity, and theta coherence arranges the firing order of principal neurons throughout the hippocampal formation. In contrast, gamma coherence reflects the coupling of active neuronal ensembles. Overall, the coherence of LFPs between different areas of the brain is an important physiological process based on the synchronized neuronal firing, and it is essential for cooperative information processing.
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Affiliation(s)
- Ivan Mysin
- Laboratory of Systemic Organization of Neurons, Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
| | - Liubov Shubina
- Laboratory of Systemic Organization of Neurons, Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
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19
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Modeling intrahippocampal effects of anterior hippocampal hyperactivity relevant to schizophrenia using chemogenetic excitation of long axis-projecting mossy cells in the mouse dentate gyrus. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2021; 1:101-111. [PMID: 34414387 PMCID: PMC8372626 DOI: 10.1016/j.bpsgos.2021.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Background The anterior hippocampus of individuals with early psychosis or schizophrenia is hyperactive, as is the ventral hippocampus in many rodent models for schizophrenia risk. Mossy cells (MCs) of the ventral dentate gyrus (DG) densely project in the hippocampal long axis, targeting both dorsal DG granule cells and inhibitory interneurons. MCs are responsive to stimulation throughout hippocampal subfields and thus may be suited to detect hyperactivity in areas where it originates such as CA1. Here, we tested the hypothesis that hyperactivation of ventral MCs activates dorsal DG granule cells to influence dorsal hippocampal function. Methods In CD-1 mice, we targeted dorsal DG-projecting ventral MCs using an adeno-associated virus intersectional strategy. In vivo fiber photometry recording of ventral MCs was performed during exploratory behaviors. We used excitatory chemogenetic constructs to test the effects of ventral MC hyperactivation on long-term spatial memory during an object location memory task. Results Photometry revealed that ventral MCs were activated during exploratory rearing. Ventral MCs made functional monosynaptic inputs to dorsal DG granule cells, and chemogenetic activation of ventral MCs modestly increased activity of dorsal DG granule cells measured by c-Fos. Finally, chemogenetic activation of ventral MCs during the training phase of an object location memory task impaired test performance 24 hours later, without effects on locomotion or object exploration. Conclusions These data suggest that ventral MC activation can directly excite dorsal granule cells and interfere with dorsal DG function, supporting future study of their in vivo activity in animal models for schizophrenia featuring ventral hyperactivity.
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20
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Dvorak D, Chung A, Park EH, Fenton AA. Dentate spikes and external control of hippocampal function. Cell Rep 2021; 36:109497. [PMID: 34348165 PMCID: PMC8369486 DOI: 10.1016/j.celrep.2021.109497] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 06/04/2021] [Accepted: 07/14/2021] [Indexed: 11/11/2022] Open
Abstract
Mouse hippocampus CA1 place-cell discharge typically encodes current location, but during slow gamma dominance (SGdom), when SG oscillations (30-50 Hz) dominate mid-frequency gamma oscillations (70-90 Hz) in CA1 local field potentials, CA1 discharge switches to represent distant recollected locations. We report that dentate spike type 2 (DSM) events initiated by medial entorhinal cortex II (MECII)→ dentate gyrus (DG) inputs promote SGdom and change excitation-inhibition coordinated discharge in DG, CA3, and CA1, whereas type 1 (DSL) events initiated by lateral entorhinal cortex II (LECII)→DG inputs do not. Just before SGdom, LECII-originating SG oscillations in DG and CA3-originating SG oscillations in CA1 phase and frequency synchronize at the DSM peak when discharge within DG and CA3 increases to promote excitation-inhibition cofiring within and across the DG→CA3→CA1 pathway. This optimizes discharge for the 5-10 ms DG-to-CA1 neuro-transmission that SGdom initiates. DSM properties identify extrahippocampal control of SGdom and a cortico-hippocampal mechanism that switches between memory-related modes of information processing.
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Affiliation(s)
- Dino Dvorak
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Ain Chung
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Eun Hye Park
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - André Antonio Fenton
- Center for Neural Science, New York University, New York, NY 10003, USA; Neuroscience Institute at the NYU Langone Medical Center, New York, NY 10003, USA.
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21
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Ibrahim KM, Ariffin MZ, Khanna S. Modulation of Septo-Hippocampal Neural Responses in Anesthetized and Behaving Rats by Septal AMPA Receptor Mechanisms. Front Neural Circuits 2021; 15:663633. [PMID: 34177470 PMCID: PMC8220821 DOI: 10.3389/fncir.2021.663633] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 05/06/2021] [Indexed: 01/14/2023] Open
Abstract
This study explored the effects of septal glutamatergic transmission on septal-hippocampal theta activity via intraseptal microinjection of antagonist at AMPA receptors (AMPAR). The current results showed that microinjection of AMPAR antagonist, NBQX (2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione, 20 μg/μl, 0.5 μl), evoked a decrease in the frequency of theta activity evoked by various means in anesthetized and behaving rat. Theta wave activity was induced on: (a) intraseptal microinjection of carbachol, an agonist at cholinergic receptors, (b) reticular stimulation, (c) exploration in novel open field (OF), and (d) hind paw (HP) injection of the algogen, formalin. The effect on frequency in the formalin test was observed in an early period on injection of formalin, which was novel to the animal, but not in the later more sustained phase of the formalin test. The effect of NBQX, being seen in both anesthetized and behaving animals, suggests that the modulation of theta wave frequency, including in novelty, is a function of AMPAR in MS. The effect of the antagonist on theta power was less apparent, being observed only in anesthetized animals. In addition to theta power and frequency, intraseptal NBQX also attenuated suppression of CA1 population spike (PS) induced by intraseptal carbachol, thus suggesting that septal glutamate neurotransmission is involved in the spectrum of MS-mediated network responses. Indeed, in the context of behavior, formalin injection induced an increase in the level of septal glutamate, while NBQX attenuated nociceptive behaviors. Notably, MS is involved in the modulation of formalin nociception. These findings suggest that AMPA receptors are a key modulator of septal physiological function.
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Affiliation(s)
- Khairunisa Mohamad Ibrahim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Mohammed Zacky Ariffin
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Sanjay Khanna
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore.,Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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22
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Balog M, Blažetić S, Ivić V, Labak I, Krajnik B, Marin R, Canerina-Amaro A, de Pablo DP, Bardak A, Gaspar R, Szűcs KF, Vari SG, Heffer M. Disarranged neuroplastin environment upon aging and chronic stress recovery in female Sprague Dawley rats. Eur J Neurosci 2021; 55:2474-2490. [PMID: 33909305 PMCID: PMC9290558 DOI: 10.1111/ejn.15256] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 04/14/2021] [Accepted: 04/21/2021] [Indexed: 11/27/2022]
Abstract
Chronic stress produces long-term metabolic changes throughout the superfamily of nuclear receptors, potentially causing various pathologies. Sex hormones modulate the stress response and generate a sex-specific age-dependent metabolic imprint, especially distinct in the reproductive senescence of females. We monitored chronic stress recovery in two age groups of female Sprague Dawley rats to determine whether stress and/or aging structurally changed the glycolipid microenvironment, a milieu playing an important role in cognitive functions. Old females experienced memory impairment even at basal conditions, which was additionally amplified by stress. On the other hand, the memory of young females was not disrupted. Stress recovery was followed by a microglial decrease and an increase in astrocyte count in the hippocampal immune system. Since dysfunction of the brain immune system could contribute to disturbed synaptogenesis, we analyzed neuroplastin expression and the lipid environment. Neuroplastin microenvironments were explored by analyzing immunofluorescent stainings using a newly developed Python script method. Stress reorganized glycolipid microenvironment in the Cornu Ammonis 1 (CA1) and dentate gyrus (DG) hippocampal regions of old females but in a very different fashion, thus affecting neuroplasticity. The postulation of four possible neuroplastin environments pointed to the GD1a ganglioside enrichment during reproductive senescence of stressed females, as well as its high dispersion in both regions and to GD1a and GM1 loss in the CA1 region. A specific lipid environment might influence neuroplastin functionality and underlie synaptic dysfunction triggered by a combination of aging and chronic stress.
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Affiliation(s)
- Marta Balog
- Department of Medical Biology and Genetics, Faculty of Medicine, J. J. Strossmayer University of Osijek, Osijek, Croatia
| | - Senka Blažetić
- Department of Biology, J. J. Strossmayer University of Osijek, Osijek, Croatia
| | - Vedrana Ivić
- Department of Medical Biology and Genetics, Faculty of Medicine, J. J. Strossmayer University of Osijek, Osijek, Croatia
| | - Irena Labak
- Department of Biology, J. J. Strossmayer University of Osijek, Osijek, Croatia
| | - Bartosz Krajnik
- Department of Experimental Physics, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Raquel Marin
- Laboratory of Cellular Neurobiology, Department of Basic Medical Sciences, School of Health Sciences, Universidad de La Laguna, La Laguna, Spain
| | - Ana Canerina-Amaro
- Laboratory of Cellular Neurobiology, Department of Basic Medical Sciences, School of Health Sciences, Universidad de La Laguna, La Laguna, Spain
| | - Daniel Pereda de Pablo
- Laboratory of Cellular Neurobiology, Department of Basic Medical Sciences, School of Health Sciences, Universidad de La Laguna, La Laguna, Spain
| | - Ana Bardak
- Department of Medical Biology and Genetics, Faculty of Medicine, J. J. Strossmayer University of Osijek, Osijek, Croatia
| | - Robert Gaspar
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Kálmán Ferenc Szűcs
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Sandor G Vari
- Cedars-Sinai Medical Center, International Research and Innovation in Medicine Program, Los Angeles, CA, USA
| | - Marija Heffer
- Department of Medical Biology and Genetics, Faculty of Medicine, J. J. Strossmayer University of Osijek, Osijek, Croatia
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23
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Fernández-Ruiz A, Oliva A, Soula M, Rocha-Almeida F, Nagy GA, Martin-Vazquez G, Buzsáki G. Gamma rhythm communication between entorhinal cortex and dentate gyrus neuronal assemblies. Science 2021; 372:eabf3119. [PMID: 33795429 PMCID: PMC8285088 DOI: 10.1126/science.abf3119] [Citation(s) in RCA: 105] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 01/29/2021] [Indexed: 01/02/2023]
Abstract
Gamma oscillations are thought to coordinate the spike timing of functionally specialized neuronal ensembles across brain regions. To test this hypothesis, we optogenetically perturbed gamma spike timing in the rat medial (MEC) and lateral (LEC) entorhinal cortices and found impairments in spatial and object learning tasks, respectively. MEC and LEC were synchronized with the hippocampal dentate gyrus through high- and low-gamma-frequency rhythms, respectively, and engaged either granule cells or mossy cells and CA3 pyramidal cells in a task-dependent manner. Gamma perturbation disrupted the learning-induced assembly organization of target neurons. Our findings imply that pathway-specific gamma oscillations route task-relevant information between distinct neuronal subpopulations in the entorhinal-hippocampal circuit. We hypothesize that interregional gamma-time-scale spike coordination is a mechanism of neuronal communication.
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Affiliation(s)
- Antonio Fernández-Ruiz
- New York University Neuroscience Institute, New York University, New York, NY 10016, USA.
| | - Azahara Oliva
- New York University Neuroscience Institute, New York University, New York, NY 10016, USA
- Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Marisol Soula
- New York University Neuroscience Institute, New York University, New York, NY 10016, USA
| | - Florbela Rocha-Almeida
- New York University Neuroscience Institute, New York University, New York, NY 10016, USA
- Division of Neurosciences, University Pablo de Olavide, 41013 Seville, Spain
| | - Gergo A Nagy
- New York University Neuroscience Institute, New York University, New York, NY 10016, USA
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Szigony utca 43, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, H-1085 Budapest, Üllői út 26, Hungary
| | - Gonzalo Martin-Vazquez
- Department of Theoretical Physics, Complutense University, 28040 Madrid, Spain
- School of Experimental Sciences, University Francisco de Vitoria, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - György Buzsáki
- New York University Neuroscience Institute, New York University, New York, NY 10016, USA.
- Center for Neural Science, New York University, New York, NY 10016, USA
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24
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Rao G, Lee H, Gallagher M, Knierim JJ. Decreased investigatory head scanning during exploration in learning-impaired, aged rats. Neurobiol Aging 2021; 98:1-9. [PMID: 33221571 PMCID: PMC8639103 DOI: 10.1016/j.neurobiolaging.2020.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 08/23/2020] [Accepted: 10/08/2020] [Indexed: 01/04/2023]
Abstract
"Head scanning" is an investigatory behavior that has been linked to spatial exploration and the one-trial formation or strengthening of place cells in the hippocampus. Previous studies have demonstrated that a subset of aged rats with normal spatial learning performance show head scanning rates during a novel, local-global cue-mismatch manipulation that are similar to those of young rats. However, these aged rats demonstrated different patterns of expression of neural activity markers in brain regions associated with spatial learning, perhaps suggesting neural mechanisms that compensate for age-related brain changes. These prior studies did not investigate the head scanning properties of aged rats that had spatial learning impairments. The present study analyzed head scanning behavior in young, aged-unimpaired, and aged-impaired Long Evans rats. Aged-impaired rats performed the head scan behavior at a lower rate than the young rats. These results suggest that decreased attention to spatial landmarks may be a contributing factor to the spatial learning deficits shown by the aged-impaired rats.
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Affiliation(s)
- Geeta Rao
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA.
| | - Heekyung Lee
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Michela Gallagher
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - James J Knierim
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA; Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
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25
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Garcia-Cortadella R, Schwesig G, Jeschke C, Illa X, Gray AL, Savage S, Stamatidou E, Schiessl I, Masvidal-Codina E, Kostarelos K, Guimerà-Brunet A, Sirota A, Garrido JA. Graphene active sensor arrays for long-term and wireless mapping of wide frequency band epicortical brain activity. Nat Commun 2021; 12:211. [PMID: 33431878 PMCID: PMC7801381 DOI: 10.1038/s41467-020-20546-w] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 12/08/2020] [Indexed: 01/29/2023] Open
Abstract
Graphene active sensors have demonstrated promising capabilities for the detection of electrophysiological signals in the brain. Their functional properties, together with their flexibility as well as their expected stability and biocompatibility have raised them as a promising building block for large-scale sensing neural interfaces. However, in order to provide reliable tools for neuroscience and biomedical engineering applications, the maturity of this technology must be thoroughly studied. Here, we evaluate the performance of 64-channel graphene sensor arrays in terms of homogeneity, sensitivity and stability using a wireless, quasi-commercial headstage and demonstrate the biocompatibility of epicortical graphene chronic implants. Furthermore, to illustrate the potential of the technology to detect cortical signals from infra-slow to high-gamma frequency bands, we perform proof-of-concept long-term wireless recording in a freely behaving rodent. Our work demonstrates the maturity of the graphene-based technology, which represents a promising candidate for chronic, wide frequency band neural sensing interfaces.
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Affiliation(s)
- R Garcia-Cortadella
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain
| | - G Schwesig
- Bernstein Center for Computational Neuroscience Munich, Faculty of Medicine, Ludwig-Maximilians Universität München, Planegg-Martinsried, Germany
| | - C Jeschke
- Multi Channel Systems (MCS) GmbH, Reutlingen, Germany
| | - X Illa
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Anna L Gray
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - S Savage
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - E Stamatidou
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - I Schiessl
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - E Masvidal-Codina
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - K Kostarelos
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - A Guimerà-Brunet
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - A Sirota
- Bernstein Center for Computational Neuroscience Munich, Faculty of Medicine, Ludwig-Maximilians Universität München, Planegg-Martinsried, Germany.
| | - J A Garrido
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain.
- ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain.
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26
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Post-inflammatory behavioural despair in male mice is associated with reduced cortical glutamate-glutamine ratios, and circulating lipid and energy metabolites. Sci Rep 2020; 10:16857. [PMID: 33033375 PMCID: PMC7545201 DOI: 10.1038/s41598-020-74008-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 09/10/2020] [Indexed: 12/13/2022] Open
Abstract
Post-inflammatory behaviours in rodents are widely used to model human depression and to test the efficacy of novel anti-depressants. Mice injected with lipopolysaccharide (LPS) display a depressive-like phenotype twenty-four hours after endotoxin administration. Despite the widespread use of this model, the mechanisms that underlie the persistent behavioural changes after the transient peripheral inflammatory response remain elusive. The study of the metabolome, the collection of all the small molecule metabolites in a sample, combined with multivariate statistical techniques provides a way of studying biochemical pathways influenced by an LPS challenge. Adult male CD-1 mice received an intraperitoneal injection of either LPS (0.83 mg/kg) or saline, and were assessed for depressive-like behaviour 24 h later. In a separate mouse cohort, pro-inflammatory cytokine gene expression and 1H nuclear magnetic resonance (NMR) metabolomics measurements were made in brain tissue and blood. Statistical analyses included Independent Sample t-tests for gene expression data, and supervised multi-variate analysis using orthogonal partial least squares discriminant analysis for metabolomics. Both plasma and brain metabolites in male mice were altered following a single peripheral LPS challenge that led to depressive-like behaviour in the forced swim test. The plasma metabolites altered by LPS are involved in energy metabolism, including lipoproteins, glucose, creatine, and isoleucine. In the brain, glutamate, serine, and N-acetylaspartate (NAA) were reduced after LPS, whereas glutamine was increased. Serine-modulated glutamatergic signalling and changes in bioenergetics may mediate the behavioural phenotype induced by LPS. In light of other data supporting a central imbalance of glutamate-glutamine cycling in depression, our results suggest that aberrant central glutaminergic signalling may underpin the depressive-like behaviours that result from both inflammation and non-immune pathophysiology. Normalising glutaminergic signalling, rather than seeking to increase serotonergic signalling, might prove to be a more coherent approach to the development of new treatments for mood disorder.
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27
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López-Madrona VJ, Pérez-Montoyo E, Álvarez-Salvado E, Moratal D, Herreras O, Pereda E, Mirasso CR, Canals S. Different theta frameworks coexist in the rat hippocampus and are coordinated during memory-guided and novelty tasks. eLife 2020; 9:57313. [PMID: 32687054 PMCID: PMC7413668 DOI: 10.7554/elife.57313] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/19/2020] [Indexed: 12/31/2022] Open
Abstract
Hippocampal firing is organized in theta sequences controlled by internal memory processes and by external sensory cues, but how these computations are coordinated is not fully understood. Although theta activity is commonly studied as a unique coherent oscillation, it is the result of complex interactions between different rhythm generators. Here, by separating hippocampal theta activity in three different current generators, we found epochs with variable theta frequency and phase coupling, suggesting flexible interactions between theta generators. We found that epochs of highly synchronized theta rhythmicity preferentially occurred during behavioral tasks requiring coordination between internal memory representations and incoming sensory information. In addition, we found that gamma oscillations were associated with specific theta generators and the strength of theta-gamma coupling predicted the synchronization between theta generators. We propose a mechanism for segregating or integrating hippocampal computations based on the flexible coordination of different theta frameworks to accommodate the cognitive needs.
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Affiliation(s)
- Víctor J López-Madrona
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, San Juan de Alicante, Spain
| | - Elena Pérez-Montoyo
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, San Juan de Alicante, Spain
| | - Efrén Álvarez-Salvado
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, San Juan de Alicante, Spain
| | - David Moratal
- Centro de Biomateriales e Ingeniería Tisular, Universitat Politècnica de València, Valencia, Spain
| | - Oscar Herreras
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Ernesto Pereda
- Departamento de Ingeniería Industrial & IUNE, Escuela Superior de Ingeniería y Tecnología, Universidad de La Laguna, La Laguna, Spain.,Laboratory of Cognitive and Computational Neuroscience, Center for Biomedical Technology, Madrid, Spain
| | - Claudio R Mirasso
- Instituto de Física Interdisciplinar y Sistemas Complejos, IFISC (CSIC-UIB), Campus Universitat de les Illes Balears, Palma de Mallorca, Spain
| | - Santiago Canals
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, San Juan de Alicante, Spain
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28
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Schultheiss NW, Schlecht M, Jayachandran M, Brooks DR, McGlothan JL, Guilarte TR, Allen TA. Awake delta and theta-rhythmic hippocampal network modes during intermittent locomotor behaviors in the rat. Behav Neurosci 2020; 134:529-546. [PMID: 32672989 DOI: 10.1037/bne0000409] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Delta-frequency network activity is commonly associated with sleep or behavioral disengagement accompanied by a dearth of cortical spiking, but delta in awake behaving animals is not well understood. We show that hippocampal (HC) synchronization in the delta frequency band (1-4 Hz) is related to animals' locomotor behavior using detailed analyses of the HC local field potential (LFP) and simultaneous head- and body-tracking data. In contrast to running-speed modulation of the theta rhythm (6-10 Hz), delta was most prominent when animals were stationary or moving slowly, that is, when theta and fast gamma (65-120 Hz) were weak, and often developed rapidly when animals paused briefly between runs. We next combined time-frequency decomposition of the LFP with hierarchical clustering algorithms to categorize momentary estimations of the power spectral density (PSD) into putative modes of HC activity. Delta and theta power were strikingly orthogonal across spectral modes, as well as across bouts of precisely defined running and stationary behavior. Delta-band and theta-band coherences between HC recording sites were monotonically related to theta-delta ratios across modes; and whereas theta coherence between HC and medial prefrontal cortex (mPFC) increased during running, delta-band coherence between mPFC and HC increased during stationary bouts. Taken together, our findings suggest that delta-dominated network modes (and corresponding mPFC-HC couplings) represent functionally distinct circuit dynamics that are temporally and behaviorally interspersed among theta-dominated modes during navigation. As such, delta modes could play a fundamental role in coordinating encoding and retrieval mechanisms or decision-making processes at a timescale that segments event sequences within behavioral episodes. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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Affiliation(s)
| | | | | | - Deborah R Brooks
- Department of Environmental Health Sciences, Robert Stempel College of Public Health, Florida International University
| | - Jennifer L McGlothan
- Department of Environmental Health Sciences, Robert Stempel College of Public Health, Florida International University
| | - Tomás R Guilarte
- Department of Environmental Health Sciences, Robert Stempel College of Public Health, Florida International University
| | - Timothy A Allen
- Cognitive Neuroscience Program, Robert Stempel College of Public Health, Florida International University
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29
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Faraji J, Metz GAS. Infrared Thermography Reveals Sex-Specific Responses to Stress in Mice. Front Behav Neurosci 2020; 14:79. [PMID: 32523518 PMCID: PMC7261839 DOI: 10.3389/fnbeh.2020.00079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/28/2020] [Indexed: 01/20/2023] Open
Abstract
Psychogenic hyperthermia is a stress-related condition reported mostly in women. Neuroendocrine responses to stress in females differ from those in males, and these differences cannot be explained solely based on hypothalamic-pituitary-adrenal (HPA) axis activity. Here, we used infrared (IR) thermographic imaging to record changes in cutaneous temperature following two types of stressful experiences in female and male mice. Mice were exposed to either single-session restraint stress or vertical exploration (rearing) deprivation and were monitored for exploratory activity and IR surface thermal changes. Females displayed higher rearing activity than males during the dark phase of the light cycle. Both sexes showed similar plasma corticosterone (CORT) responses after a challenge with restraint and rearing deprivation. However, only females responded to rearing deprivation with increased cutaneous temperature in the head and back, and a reduced thermal response in the tail. Circulating CORT levels were not correlated with the thermal variations. These findings, for the first time, provide evidence for sex-specific cutaneous thermal responses to short-term stress in mice following transient vertical-activity deprivation that may mimic clinical psychogenic hyperthermia.
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Affiliation(s)
- Jamshid Faraji
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada.,Faculty of Nursing & Midwifery, Golestan University of Medical Sciences, Gorgan, Iran
| | - Gerlinde A S Metz
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
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30
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Braganza O, Mueller-Komorowska D, Kelly T, Beck H. Quantitative properties of a feedback circuit predict frequency-dependent pattern separation. eLife 2020; 9:53148. [PMID: 32077850 PMCID: PMC7032930 DOI: 10.7554/elife.53148] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 01/20/2020] [Indexed: 12/16/2022] Open
Abstract
Feedback inhibitory motifs are thought to be important for pattern separation across species. How feedback circuits may implement pattern separation of biologically plausible, temporally structured input in mammals is, however, poorly understood. We have quantitatively determined key properties of netfeedback inhibition in the mouse dentate gyrus, a region critically involved in pattern separation. Feedback inhibition is recruited steeply with a low dynamic range (0% to 4% of active GCs), and with a non-uniform spatial profile. Additionally, net feedback inhibition shows frequency-dependent facilitation, driven by strongly facilitating mossy fiber inputs. Computational analyses show a significant contribution of the feedback circuit to pattern separation of theta modulated inputs, even within individual theta cycles. Moreover, pattern separation was selectively boosted at gamma frequencies, in particular for highly similar inputs. This effect was highly robust, suggesting that frequency-dependent pattern separation is a key feature of the feedback inhibitory microcircuit. You can probably recall where you left your car this morning without too much trouble. But assuming you use the same busy parking lot every day, can you remember which space you parked in yesterday? Or the day before that? Most people find this difficult not because they cannot remember what happened two or three days ago, but because it requires distinguishing between very similar memories. The car, the parking lot, and the time of day were the same on each occasion. So how do you remember where you parked this morning? This ability to distinguish between memories of similar events depends on a brain region called the hippocampus. A subregion of the hippocampus called the dentate gyrus generates different patterns of activity in response to events that are similar but distinct. This process is called pattern separation, and it helps ensure that you do not look for your car in yesterday’s parking space. Pattern separation in the dentate gyrus is thought to involve a form of negative feedback called feedback inhibition, a phenomenon where the output of a process acts to limit or stop the same process. To test this idea, Braganza et al. studied feedback inhibition in the dentate gyrus of mice, before building a computer model simulating the inhibition process and supplying the model with two types of realistic input. The first consisted of low-frequency theta brainwaves, which occur, for instance, in the dentate gyrus when animals explore their environment. The second consisted of higher frequency gamma brainwaves, which occur, for example, when animals experience something new. Testing the model showed that feedback inhibition contributes to pattern separation with both theta and gamma inputs. However, pattern separation is stronger with gamma input. This suggests that high frequency brainwaves in the hippocampus could help animals distinguish new events from old ones by promoting pattern separation. Various brain disorders, including Alzheimer’s disease, schizophrenia and epilepsy, involve changes in the dentate gyrus and altered brain rhythms. The current findings could help reveal how these changes contribute to memory impairments and to a reduced ability to distinguish similar experiences.
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Affiliation(s)
- Oliver Braganza
- Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany
| | - Daniel Mueller-Komorowska
- Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany.,International Max Planck Research School for Brain and Behavior, University of Bonn, Bonn, Germany
| | - Tony Kelly
- Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany
| | - Heinz Beck
- Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany
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31
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Abstract
Mammals have evolved specialized brain systems to support efficient navigation within diverse habitats and over varied distances, but while navigational strategies and sensory mechanisms vary across species, core spatial components appear to be widely shared. This review presents common elements found in mammalian spatial mapping systems, focusing on the cells in the hippocampal formation representing orientational and locational spatial information, and 'core' mammalian hippocampal circuitry. Mammalian spatial mapping systems make use of both allothetic cues (space-defining cues in the external environment) and idiothetic cues (cues derived from self-motion). As examples of each cue type, we discuss: environmental boundaries, which control both orientational and locational neuronal activity and behaviour; and 'path integration', a process that allows the estimation of linear translation from velocity signals, thought to depend upon grid cells in the entorhinal cortex. Building cognitive maps entails sampling environments: we consider how the mapping system controls exploration to acquire spatial information, and how exploratory strategies may integrate idiothetic with allothetic information. We discuss how 'replay' may act to consolidate spatial maps, and simulate trajectories to aid navigational planning. Finally, we discuss grid cell models of vector navigation.
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Affiliation(s)
| | - Tom Hartley
- Department of Psychology, University of York, YO10 5DD, UK
| | - Colin Lever
- Psychology Department, Durham University, DH1 3LE, UK.
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