1
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Ueta Y, Miyata M. Functional and structural synaptic remodeling mechanisms underlying somatotopic organization and reorganization in the thalamus. Neurosci Biobehav Rev 2023; 152:105332. [PMID: 37524138 DOI: 10.1016/j.neubiorev.2023.105332] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/09/2023] [Accepted: 07/27/2023] [Indexed: 08/02/2023]
Abstract
The somatosensory system organizes the topographic representation of body maps, termed somatotopy, at all levels of an ascending hierarchy. Postnatal maturation of somatotopy establishes optimal somatosensation, whereas deafferentation in adults reorganizes somatotopy, which underlies pathological somatosensation, such as phantom pain and complex regional pain syndrome. Here, we focus on the mouse whisker somatosensory thalamus to study how sensory experience shapes the fine topography of afferent connectivity during the critical period and what mechanisms remodel it and drive a large-scale somatotopic reorganization after peripheral nerve injury. We will review our findings that, following peripheral nerve injury in adults, lemniscal afferent synapses onto thalamic neurons are remodeled back to immature configuration, as if the critical period reopens. The remodeling process is initiated with local activation of microglia in the brainstem somatosensory nucleus downstream to injured nerves and heterosynaptically controlled by input from GABAergic and cortical neurons to thalamic neurons. These fruits of thalamic studies complement well-studied cortical mechanisms of somatotopic organization and reorganization and unveil potential intervention points in treating pathological somatosensation.
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Affiliation(s)
- Yoshifumi Ueta
- Division of Neurophysiology, Department of Physiology, School of Medicine, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Mariko Miyata
- Division of Neurophysiology, Department of Physiology, School of Medicine, Tokyo Women's Medical University, Tokyo 162-8666, Japan.
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2
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The Pedunculopontine Tegmental Nucleus is not Important for Breathing Impairments Observed in a Parkinson's Disease Model. Neuroscience 2023; 512:32-46. [PMID: 36690033 DOI: 10.1016/j.neuroscience.2022.12.022] [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: 09/01/2022] [Revised: 12/15/2022] [Accepted: 12/20/2022] [Indexed: 01/21/2023]
Abstract
Parkinson's disease (PD) is a motor disorder resulting from degeneration of dopaminergic neurons of substantia nigra pars compacta (SNpc), with classical and non-classical symptoms such as respiratory instability. An important region for breathing control, the Pedunculopontine Tegmental Nucleus (PPTg), is composed of cholinergic, glutamatergic, and GABAergic neurons. We hypothesize that degenerated PPTg neurons in a PD model contribute to the blunted respiratory activity. Adult mice (40 males and 29 females) that express the fluorescent green protein in cholinergic, glutamatergic or GABAergic cells were used (Chat-cre Ai6, Vglut2-cre Ai6 and Vgat-cre Ai6) and received bilateral intrastriatal injections of vehicle or 6-hydroxydopamine (6-OHDA). Ten days later, the animals were exposed to hypercapnia or hypoxia to activate PPTg neurons. Vglut2-cre Ai6 animals also received retrograde tracer injections (cholera toxin b) into the retrotrapezoid nucleus (RTN) or preBötzinger Complex (preBötC) and anterograde tracer injections (AAV-mCherry) into the SNpc. In 6-OHDA-injected mice, there is a 77% reduction in the number of dopaminergic neurons in SNpc without changing the number of neurons in the PPTg. Hypercapnia activated fewer Vglut2 neurons in PD, and hypoxia did not activate PPTg neurons. PPTg neurons do not input RTN or preBötC regions but receive projections from SNpc. Although our results did not show a reduction in the number of glutamatergic neurons in PPTg, we observed a reduction in the number of neurons activated by hypercapnia in the PD animal model, suggesting that PPTg may participate in the hypercapnia ventilatory response.
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3
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Revah O, Gore F, Kelley KW, Andersen J, Sakai N, Chen X, Li MY, Birey F, Yang X, Saw NL, Baker SW, Amin ND, Kulkarni S, Mudipalli R, Cui B, Nishino S, Grant GA, Knowles JK, Shamloo M, Huguenard JR, Deisseroth K, Pașca SP. Maturation and circuit integration of transplanted human cortical organoids. Nature 2022; 610:319-326. [PMID: 36224417 PMCID: PMC9556304 DOI: 10.1038/s41586-022-05277-w] [Citation(s) in RCA: 122] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 08/25/2022] [Indexed: 01/26/2023]
Abstract
Self-organizing neural organoids represent a promising in vitro platform with which to model human development and disease1-5. However, organoids lack the connectivity that exists in vivo, which limits maturation and makes integration with other circuits that control behaviour impossible. Here we show that human stem cell-derived cortical organoids transplanted into the somatosensory cortex of newborn athymic rats develop mature cell types that integrate into sensory and motivation-related circuits. MRI reveals post-transplantation organoid growth across multiple stem cell lines and animals, whereas single-nucleus profiling shows progression of corticogenesis and the emergence of activity-dependent transcriptional programs. Indeed, transplanted cortical neurons display more complex morphological, synaptic and intrinsic membrane properties than their in vitro counterparts, which enables the discovery of defects in neurons derived from individuals with Timothy syndrome. Anatomical and functional tracings show that transplanted organoids receive thalamocortical and corticocortical inputs, and in vivo recordings of neural activity demonstrate that these inputs can produce sensory responses in human cells. Finally, cortical organoids extend axons throughout the rat brain and their optogenetic activation can drive reward-seeking behaviour. Thus, transplanted human cortical neurons mature and engage host circuits that control behaviour. We anticipate that this approach will be useful for detecting circuit-level phenotypes in patient-derived cells that cannot otherwise be uncovered.
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Affiliation(s)
- Omer Revah
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, CA, USA
| | - Felicity Gore
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Kevin W Kelley
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, CA, USA
| | - Jimena Andersen
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, CA, USA
| | - Noriaki Sakai
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Xiaoyu Chen
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, CA, USA
| | - Min-Yin Li
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, CA, USA
| | - Fikri Birey
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, CA, USA
| | - Xiao Yang
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, CA, USA
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Nay L Saw
- Stanford Behavioral and Functional Neuroscience Laboratory, Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
| | - Samuel W Baker
- Department of Comparative Medicine, Stanford University, Stanford, CA, USA
| | - Neal D Amin
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, CA, USA
| | - Shravanti Kulkarni
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, CA, USA
| | - Rachana Mudipalli
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Bianxiao Cui
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Seiji Nishino
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Gerald A Grant
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Juliet K Knowles
- Department of Neurology and Neurological Sciences, Stanford, CA, USA
| | - Mehrdad Shamloo
- Stanford Behavioral and Functional Neuroscience Laboratory, Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford, CA, USA
| | - Karl Deisseroth
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Sergiu P Pașca
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA.
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, CA, USA.
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Su M, Liu J, Yu B, Zhou K, Sun C, Yang M, Zhao C. Loss of Calretinin in L5a impairs the formation of the barrel cortex leading to abnormal whisker-mediated behaviors. Mol Brain 2021; 14:67. [PMID: 33845857 PMCID: PMC8042711 DOI: 10.1186/s13041-021-00775-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/23/2021] [Indexed: 11/30/2022] Open
Abstract
The rodent whisker-barrel cortex system has been established as an ideal model for studying sensory information integration. The barrel cortex consists of barrel and septa columns that receive information input from the lemniscal and paralemniscal pathways, respectively. Layer 5a is involved in both barrel and septa circuits and play a key role in information integration. However, the role of layer 5a in the development of the barrel cortex remains unclear. Previously, we found that calretinin is dynamically expressed in layer 5a. In this study, we analyzed calretinin KO mice and found that the dendritic complexity and length of layer 5a pyramidal neurons were significantly decreased after calretinin ablation. The membrane excitability and excitatory synaptic transmission of layer 5a neurons were increased. Consequently, the organization of the barrels was impaired. Moreover, layer 4 spiny stellate cells were not able to properly gather, leading to abnormal formation of barrel walls as the ratio of barrel/septum size obviously decreased. Calretinin KO mice exhibited deficits in exploratory and whisker-associated tactile behaviors as well as social novelty preference. Our study expands our knowledge of layer 5a pyramidal neurons in the formation of barrel walls and deepens the understanding of the development of the whisker-barrel cortex system.
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Affiliation(s)
- Mingzhao Su
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Junhua Liu
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Baocong Yu
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Kaixing Zhou
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Congli Sun
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Mengjie Yang
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Chunjie Zhao
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China.
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Gharaei S, Honnuraiah S, Arabzadeh E, Stuart GJ. Superior colliculus modulates cortical coding of somatosensory information. Nat Commun 2020; 11:1693. [PMID: 32245963 PMCID: PMC7125203 DOI: 10.1038/s41467-020-15443-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 03/02/2020] [Indexed: 12/05/2022] Open
Abstract
The cortex modulates activity in superior colliculus via a direct projection. What is largely unknown is whether (and if so how) the superior colliculus modulates activity in the cortex. Here, we investigate this issue and show that optogenetic activation of superior colliculus changes the input-output relationship of neurons in somatosensory cortex, enhancing responses to low amplitude whisker deflections. While there is no direct pathway from superior colliculus to somatosensory cortex, we found that activation of superior colliculus drives spiking in the posterior medial (POm) nucleus of the thalamus via a powerful monosynaptic pathway. Furthermore, POm neurons receiving input from superior colliculus provide monosynaptic excitatory input to somatosensory cortex. Silencing POm abolished the capacity of superior colliculus to modulate cortical whisker responses. Our findings indicate that the superior colliculus, which plays a key role in attention, modulates sensory processing in somatosensory cortex via a powerful di-synaptic pathway through the thalamus.
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Affiliation(s)
- Saba Gharaei
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, ACT, Australia.
| | - Suraj Honnuraiah
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, ACT, Australia
| | - Ehsan Arabzadeh
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, ACT, Australia
| | - Greg J Stuart
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, ACT, Australia.
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6
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A Non-canonical Feedback Circuit for Rapid Interactions between Somatosensory Cortices. Cell Rep 2019; 23:2718-2731.e6. [PMID: 29847801 PMCID: PMC6004823 DOI: 10.1016/j.celrep.2018.04.115] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/20/2018] [Accepted: 04/26/2018] [Indexed: 12/17/2022] Open
Abstract
Sensory perception depends on interactions among cortical areas. These
interactions are mediated by canonical patterns of connectivity in which higher
areas send feedback projections to lower areas via neurons in superficial and
deep layers. Here, we probed the circuit basis of interactions among two areas
critical for touch perception in mice, whisker primary (wS1) and secondary (wS2)
somatosensory cortices. Neurons in layer 4 of wS2 (S2L4) formed a
major feedback pathway to wS1. Feedback from wS2 to wS1 was organized
somatotopically. Spikes evoked by whisker deflections occurred nearly as rapidly
in wS2 as in wS1, including among putative S2L4 → S1 feedback
neurons. Axons from S2L4 → S1 neurons sent stimulus
orientation-specific activity to wS1. Optogenetic excitation of S2L4
neurons modulated activity across both wS2 and wS1, while inhibition of
S2L4 reduced orientation tuning among wS1 neurons. Thus, a
non-canonical feedback circuit, originating in layer 4 of S2, rapidly modulates
early tactile processing.
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7
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Kroon T, van Hugte E, van Linge L, Mansvelder HD, Meredith RM. Early postnatal development of pyramidal neurons across layers of the mouse medial prefrontal cortex. Sci Rep 2019; 9:5037. [PMID: 30911152 PMCID: PMC6433913 DOI: 10.1038/s41598-019-41661-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 03/12/2019] [Indexed: 12/24/2022] Open
Abstract
Mammalian neocortex is a highly layered structure. Each layer is populated by distinct subtypes of principal cells that are born at different times during development. While the differences between principal cells across layers have been extensively studied, it is not known how the developmental profiles of neurons in different layers compare. Here, we provide a detailed morphological and functional characterisation of pyramidal neurons in mouse mPFC during the first postnatal month, corresponding to known critical periods for synapse and neuron formation in mouse sensory neocortex. Our data demonstrate similar maturation profiles of dendritic morphology and intrinsic properties of pyramidal neurons in both deep and superficial layers. In contrast, the balance of synaptic excitation and inhibition differs in a layer-specific pattern from one to four postnatal weeks of age. Our characterisation of the early development and maturation of pyramidal neurons in mouse mPFC not only demonstrates a comparable time course of postnatal maturation to that in other neocortical circuits, but also implies that consideration of layer- and time-specific changes in pyramidal neurons may be relevant for studies in mouse models of neuropsychiatric and neurodevelopmental disorders.
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Affiliation(s)
- Tim Kroon
- Department of Integrative Neurophysiology, Center for Neurogenomics & Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.
- MRC Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK.
| | - Eline van Hugte
- Department of Integrative Neurophysiology, Center for Neurogenomics & Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
- Department Cognitive Neurosciences, Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Geert Grooteplein 10 Noord, 6500 HB, Nijmegen, The Netherlands
| | - Lola van Linge
- Department of Integrative Neurophysiology, Center for Neurogenomics & Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
- Department of Functional Genomics, Center for Neurogenomics & Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics & Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Rhiannon M Meredith
- Department of Integrative Neurophysiology, Center for Neurogenomics & Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
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8
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Almeida-Corrêa S, Czisch M, Wotjak CT. In Vivo Visualization of Active Polysynaptic Circuits With Longitudinal Manganese-Enhanced MRI (MEMRI). Front Neural Circuits 2018; 12:42. [PMID: 29887796 PMCID: PMC5981681 DOI: 10.3389/fncir.2018.00042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 04/30/2018] [Indexed: 12/23/2022] Open
Abstract
Manganese-enhanced magnetic resonance imaging (MEMRI) is a powerful tool for in vivo non-invasive whole-brain mapping of neuronal activity. Mn2+ enters active neurons via voltage-gated calcium channels and increases local contrast in T1-weighted images. Given the property of Mn2+ of axonal transport, this technique can also be used for tract tracing after local administration of the contrast agent. However, MEMRI is still not widely employed in basic research due to the lack of a complete description of the Mn2+ dynamics in the brain. Here, we sought to investigate how the activity state of neurons modulates interneuronal Mn2+ transport. To this end, we injected mice with low dose MnCl2 2. (i.p., 20 mg/kg; repeatedly for 8 days) followed by two MEMRI scans at an interval of 1 week without further MnCl2 injections. We assessed changes in T1 contrast intensity before (scan 1) and after (scan 2) partial sensory deprivation (unilateral whisker trimming), while keeping the animals in a sensory enriched environment. After correcting for the general decay in Mn2+ content, whole brain analysis revealed a single cluster with higher signal in scan 1 compared to scan 2: the left barrel cortex corresponding to the right untrimmed whiskers. In the inverse contrast (scan 2 > scan 1), a number of brain structures, including many efferents of the left barrel cortex were observed. These results suggest that continuous neuronal activity elicited by ongoing sensory stimulation accelerates Mn2+ transport from the uptake site to its projection terminals, while the blockage of sensory-input and the resulting decrease in neuronal activity attenuates Mn2+ transport. The description of this critical property of Mn2+ dynamics in the brain allows a better understanding of MEMRI functional mechanisms, which will lead to more carefully designed experiments and clearer interpretation of the results.
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Affiliation(s)
- Suellen Almeida-Corrêa
- Department of Stress Neurobiology & Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Michael Czisch
- Core Unit Neuroimaging, Max Planck Institute of Psychiatry, Munich, Germany
| | - Carsten T Wotjak
- Department of Stress Neurobiology & Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
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9
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Abstract
Somatosensory areas containing topographic maps of the body surface are a major feature of parietal cortex. In primates, parietal cortex contains four somatosensory areas, each with its own map, with the primary cutaneous map in area 3b. Rodents have at least three parietal somatosensory areas. Maps are not isomorphic to the body surface, but magnify behaviorally important skin regions, which include the hands and face in primates, and the whiskers in rodents. Within each map, intracortical circuits process tactile information, mediate spatial integration, and support active sensation. Maps may also contain fine-scale representations of touch submodalities, or direction of tactile motion. Functional representations are more overlapping than suggested by textbook depictions of map topography. The whisker map in rodent somatosensory cortex is a canonic system for studying cortical microcircuits, sensory coding, and map plasticity. Somatosensory maps are plastic throughout life in response to altered use or injury. This chapter reviews basic principles and recent findings in primate, human, and rodent somatosensory maps.
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Affiliation(s)
- Samuel Harding-Forrester
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States
| | - Daniel E Feldman
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States.
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10
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Zolnik TA, Sha F, Johenning FW, Schreiter ER, Looger LL, Larkum ME, Sachdev RNS. All-optical functional synaptic connectivity mapping in acute brain slices using the calcium integrator CaMPARI. J Physiol 2016; 595:1465-1477. [PMID: 27861906 DOI: 10.1113/jp273116] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 11/04/2016] [Indexed: 01/28/2023] Open
Abstract
KEY POINTS The genetically encoded fluorescent calcium integrator calcium-modulated photoactivatable ratiobetric integrator (CaMPARI) reports calcium influx induced by synaptic and neural activity. Its fluorescence is converted from green to red in the presence of violet light and calcium. The rate of conversion - the sensitivity to activity - is tunable and depends on the intensity of violet light. Synaptic activity and action potentials can independently initiate significant CaMPARI conversion. The level of conversion by subthreshold synaptic inputs is correlated to the strength of input, enabling optical readout of relative synaptic strength. When combined with optogenetic activation of defined presynaptic neurons, CaMPARI provides an all-optical method to map synaptic connectivity. ABSTRACT The calcium-modulated photoactivatable ratiometric integrator (CaMPARI) is a genetically encoded calcium integrator that facilitates the study of neural circuits by permanently marking cells active during user-specified temporal windows. Permanent marking enables measurement of signals from large swathes of tissue and easy correlation of activity with other structural or functional labels. One potential application of CaMPARI is labelling neurons postsynaptic to specific populations targeted for optogenetic stimulation, giving rise to all-optical functional connectivity mapping. Here, we characterized the response of CaMPARI to several common types of neuronal calcium signals in mouse acute cortical brain slices. Our experiments show that CaMPARI is effectively converted by both action potentials and subthreshold synaptic inputs, and that conversion level is correlated to synaptic strength. Importantly, we found that conversion rate can be tuned: it is linearly related to light intensity. At low photoconversion light levels CaMPARI offers a wide dynamic range due to slower conversion rate; at high light levels conversion is more rapid and more sensitive to activity. Finally, we employed CaMPARI and optogenetics for functional circuit mapping in ex vivo acute brain slices, which preserve in vivo-like connectivity of axon terminals. With a single light source, we stimulated channelrhodopsin-2-expressing long-range posteromedial (POm) thalamic axon terminals in cortex and induced CaMPARI conversion in recipient cortical neurons. We found that POm stimulation triggers robust photoconversion of layer 5 cortical neurons and weaker conversion of layer 2/3 neurons. Thus, CaMPARI enables network-wide, tunable, all-optical functional circuit mapping that captures supra- and subthreshold depolarization.
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Affiliation(s)
- Timothy A Zolnik
- Neurocure Center for Excellence, Chariteplatz 1/Virchowweg 6, Charité Universitätsmedizin Berlin and Humboldt Universität, Berlin, 10117, Germany
| | - Fern Sha
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA, 20147, USA
| | - Friedrich W Johenning
- Neuroscience Research Center, Charité Universitätsmedizin Berlin, Charitéplatz 1, Berlin, 10117, Germany
| | - Eric R Schreiter
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA, 20147, USA
| | - Loren L Looger
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA, 20147, USA
| | - Matthew E Larkum
- Neurocure Center for Excellence, Chariteplatz 1/Virchowweg 6, Charité Universitätsmedizin Berlin and Humboldt Universität, Berlin, 10117, Germany
| | - Robert N S Sachdev
- Neurocure Center for Excellence, Chariteplatz 1/Virchowweg 6, Charité Universitätsmedizin Berlin and Humboldt Universität, Berlin, 10117, Germany
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11
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Abstract
Abnormal cortical circuits underlie some cognitive and psychiatric disorders, yet the molecular signals that generate normal cortical networks remain poorly understood. Semaphorin 7A (Sema7A) is an atypical member of the semaphorin family that is GPI-linked, expressed principally postnatally, and enriched in sensory cortex. Significantly, SEMA7A is deleted in individuals with 15q24 microdeletion syndrome, characterized by developmental delay, autism, and sensory perceptual deficits. We studied the role that Sema7A plays in establishing functional cortical circuitry in mouse somatosensory barrel cortex. We found that Sema7A is expressed in spiny stellate cells and GABAergic interneurons and that its absence disrupts barrel cytoarchitecture, reduces asymmetrical orientation of spiny stellate cell dendrites, and functionally impairs thalamocortically evoked synaptic responses, with reduced feed-forward GABAergic inhibition. These data identify Sema7A as a regulator of thalamocortical and local circuit development in layer 4 and provide a molecular handle that can be used to explore the coordinated generation of excitatory and inhibitory cortical circuits.
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12
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Modality-specific thalamocortical inputs instruct the identity of postsynaptic L4 neurons. Nature 2014; 511:471-4. [DOI: 10.1038/nature13390] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 04/22/2014] [Indexed: 01/17/2023]
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13
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Frangeul L, Porrero C, Garcia-Amado M, Maimone B, Maniglier M, Clascá F, Jabaudon D. Specific activation of the paralemniscal pathway during nociception. Eur J Neurosci 2014; 39:1455-64. [PMID: 24580836 DOI: 10.1111/ejn.12524] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 01/10/2014] [Accepted: 01/27/2014] [Indexed: 11/30/2022]
Abstract
Two main neuronal pathways connect facial whiskers to the somatosensory cortex in rodents: (i) the lemniscal pathway, which originates in the brainstem principal trigeminal nucleus and is relayed in the ventroposterior thalamic nucleus and (ii) the paralemniscal pathway, originating in the spinal trigeminal nucleus and relayed in the posterior thalamic nucleus. While lemniscal neurons are readily activated by whisker contacts, the contribution of paralemniscal neurons to perception is less clear. Here, we functionally investigated these pathways by manipulating input from the whisker pad in freely moving mice. We report that while lemniscal neurons readily respond to neonatal infraorbital nerve sectioning or whisker contacts in vivo, paralemniscal neurons do not detectably respond to these environmental changes. However, the paralemniscal pathway is specifically activated upon noxious stimulation of the whisker pad. These findings reveal a nociceptive function for paralemniscal neurons in vivo that may critically inform context-specific behaviour during environmental exploration.
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Affiliation(s)
- Laura Frangeul
- Department of Basic Neurosciences, University of Geneva, 1 rue Michel Servet, 1211, Geneva, Switzerland
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14
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Willing J, Wagner CK. Sensorimotor development in neonatal progesterone receptor knockout mice. Dev Neurobiol 2013; 74:16-24. [PMID: 23983142 DOI: 10.1002/dneu.22124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 08/01/2013] [Accepted: 08/20/2013] [Indexed: 11/08/2022]
Abstract
Early exposure to steroid hormones can permanently and dramatically alter neural development. This is best understood in the organizational effects of hormones during development of brain regions involved in reproductive behaviors or neuroendocrine function. However, recent evidence strongly suggests that steroid hormones play a vital role in shaping brain regions involved in cognitive behavior such as the cerebral cortex. The most abundantly expressed steroid hormone receptor in the developing rodent cortex is the progesterone receptor (PR). In the rat, PR is initially expressed in the developmentally-critical subplate at E18, and subsequently in laminas V and II/III through the first three postnatal weeks (Quadros et al. [2007] J Comp Neurol 504:42-56; Lopez & Wagner [2009]: J Comp Neurol 512:124-139), coinciding with significant periods of dendritic maturation, the arrival of afferents and synaptogenesis. In the present study, we investigated PR expression in the neonatal mouse somatosensory cortex. Additionally, to investigate the potential role of PR in developing cortex, we examined sensorimotor function in the first two postnatal weeks in PR knockout mice and their wildtype (WT) and heterozygous (HZ) counterparts. While the three genotypes were similar in most regards, PRKO and HZ mice lost the rooting reflex 2-3 days earlier than WT mice. These studies represent the first developmental behavioral assessment of PRKO mice and suggest PR expression may play an important role in the maturation of cortical connectivity and sensorimotor integration.
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Affiliation(s)
- Jari Willing
- Department of Psychology, University at Albany - SUNY, Albany, New York
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15
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Barrera K, Chu P, Abramowitz J, Steger R, Ramos RL, Brumberg JC. Organization of myelin in the mouse somatosensory barrel cortex and the effects of sensory deprivation. Dev Neurobiol 2012; 73:297-314. [PMID: 23047707 DOI: 10.1002/dneu.22060] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 09/25/2012] [Indexed: 11/10/2022]
Abstract
In rodents, the barrel cortex is a specialized area within the somatosensory cortex that processes signals from the mystacial whiskers. We investigated the normal development of myelination in the barrel cortex of mice, as well as the effects of sensory deprivation on this pattern. Deprivation was achieved by trimming the whiskers on one side of the face every other day from birth. In control mice, myelin was not present until postnatal day 14 and did not show prominence until postnatal day 30; adult levels of myelination were reached by the end of the second postnatal month. Unbiased stereology was used to estimate axon density in the interbarrel septal region and barrel walls as well as the barrel centers. Myelin was significantly more concentrated in the interbarrel septa/barrel walls than in the barrel centers in both control and sensory-deprived conditions. Sensory deprivation did not impact the onset of myelination but resulted in a significant decrease in myelinated axons in the barrel region and decreased the amount of myelin ensheathing each axon. Visualization of the oligodendrocyte nuclear marker Olig2 revealed a similar pattern of myelin as seen using histochemistry, but with no significant changes in Olig2+ nuclei following sensory deprivation. Consistent with the anatomical results showing less myelination, local field potentials revealed slower rise times following trimming. Our results suggest that myelination develops relatively late and can be influenced by sensory experience.
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Affiliation(s)
- Kyrstle Barrera
- Department of Psychology, Loma Linda University, Loma Linda, California 92350, USA
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16
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Terakawa YW, Inoue YU, Asami J, Hoshino M, Inoue T. A sharp cadherin-6 gene expression boundary in the developing mouse cortical plate demarcates the future functional areal border. ACTA ACUST UNITED AC 2012; 23:2293-308. [PMID: 22875867 DOI: 10.1093/cercor/bhs221] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mammalian cerebral cortex can be tangentially subdivided into tens of functional areas with distinct cyto-architectures and neural circuitries; however, it remains elusive how these areal borders are genetically elaborated during development. Here we establish original bacterial artificial chromosome transgenic mouse lines that specifically recapitulate cadherin-6 (Cdh6) mRNA expression profiles in the layer IV of the somatosensory cortex and by detailing their cortical development, we show that a sharp Cdh6 gene expression boundary is formed at a mediolateral coordinate along the cortical layer IV as early as the postnatal day 5 (P5). By further applying mouse genetics that allows rigid cell fate tracing with CreERT2 expression, it is demonstrated that the Cdh6 gene expression boundary set at around P4 eventually demarcates the areal border between the somatosensory barrel and limb field at P20. In the P6 cortical cell pellet culture system, neurons with Cdh6 expression preferentially form aggregates in a manner dependent on Ca(2+) and electroporation-based Cdh6 overexpression limited to the postnatal stages perturbs area-specific cell organization in the barrel field. These results suggest that Cdh6 expression in the nascent cortical plate may serve solidification of the protomap for cortical functional areas.
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Affiliation(s)
- Youhei W Terakawa
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
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17
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Zaccaria KJ, McCasland JS. Emergence of layer IV barrel cytoarchitecture is delayed in somatosensory cortex of GAP-43 deficient mice following delayed development of dendritic asymmetry. Somatosens Mot Res 2012; 29:77-88. [PMID: 22759196 DOI: 10.3109/08990220.2012.686936] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The emergence of barrel cytoarchitecture in mouse somatosensory cortex is extremely well defined. However, mechanisms underlying the development of this cellular organization are not completely understood. While it is generally accepted that hollows emerge via passive displacement of cortical cells by dense thalamocortical afferent clusters in barrel centers, it is not known what causes cellular segregation of barrel sides and septa. Here, we hypothesized that the emergence of sides and septa is related to the progressive asymmetry of dendrites from the cells of the barrel side toward the barrel hollow during development. We tested this hypothesis in the barrel cortex of growth-associated protein-43 heterozygous mice (GAP43 (+/-) mice) that display a 2-day delay in retraction of septally oriented dendrites compared to (+/+) littermates. We predicted that this delayed retraction would result in a subsequent 2-day delay in the emergence of barrel sides and septa. Using cresyl violet staining of barrel cortex, we found that initial emergence of hollows was not different between GAP43 (+/-) mice and (+/+) littermate controls. However, the emergence of sides and septa was delayed by 2 days, supporting our hypothesis that the emergence of barrel sides and septa is related to, and perhaps reliant upon, the developmental step of dendritic orientation toward barrel hollows. This process, which is mechanistically distinct from the emergence of barrel hollows, is likely due to both active and passive events resulting from asymmetric cell orientation.
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Affiliation(s)
- Kimberly J Zaccaria
- Department of Cell & Developmental Biology, SUNY Upstate Medical University, Syracuse, NY, USA.
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18
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Clascá F, Rubio-Garrido P, Jabaudon D. Unveiling the diversity of thalamocortical neuron subtypes. Eur J Neurosci 2012; 35:1524-32. [DOI: 10.1111/j.1460-9568.2012.08033.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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19
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Ohno S, Kuramoto E, Furuta T, Hioki H, Tanaka YR, Fujiyama F, Sonomura T, Uemura M, Sugiyama K, Kaneko T. A Morphological Analysis of Thalamocortical Axon Fibers of Rat Posterior Thalamic Nuclei: A Single Neuron Tracing Study with Viral Vectors. Cereb Cortex 2011; 22:2840-57. [DOI: 10.1093/cercor/bhr356] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Abstract
Large-scale neuronal networks integrating several cortical areas mediate the complex functions of the brain such as sensorimotor integration. Little is known about the functional development of these networks and the maturational processes by which distant networks become functionally connected. We addressed this question in the postnatal rat sensorimotor system. Using epicranial multielectrode grids that span most of the cortical surface and intracortical electrodes, we show that sensory evoked cortical responses continuously maturate throughout the first 3 weeks with the strongest developmental changes occurring in a very short time around postnatal day 13 (P13). Before P13, whisker stimulation evokes slow, initially surface-negative activity restricted mostly to the lateral parietal area of the contralateral hemisphere. In a narrow time window of ∼48 h around P13, a new early, sharp surface-positive component emerges that coincides with subsequent propagation of activity to sensory and motor areas of both hemispheres. Our data show that this new component developing at the end of the second week corresponds principally to functional maturation of the supragranular cortical layers and appears to be crucial for the functional associations in the large-scale sensorimotor cortical network. It goes along with the onset of whisking behavior, as well as major synaptic and functional changes within the S1 cortex that are known to develop during this period.
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Sehara K, Kawasaki H. Neuronal circuits with whisker-related patterns. Mol Neurobiol 2011; 43:155-62. [PMID: 21365361 DOI: 10.1007/s12035-011-8170-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 02/14/2011] [Indexed: 10/18/2022]
Abstract
Neuronal circuits with whisker-related patterns, such as those observed in the rodent somatosensory barrel cortex, have been widely used as a model system for investigating the anatomical organization, development and physiological roles of functional neuronal circuits. Whisker-related patterns exist not only in the barrel cortex but also in subcortical structures along the trigeminal neuraxis from the brainstem to the cortex. Here, we briefly summarize the organization, formation, and function of each neuronal circuit with whisker-related patterns, including the novel axonal trajectories that we recently found with the aid of in utero electroporation. We also discuss their biological implications as model systems for the studies of functional neuronal circuits.
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Affiliation(s)
- Keisuke Sehara
- Department of Molecular and Systems Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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22
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Dye CA, El Shawa H, Huffman KJ. A lifespan analysis of intraneocortical connections and gene expression in the mouse II. ACTA ACUST UNITED AC 2010; 21:1331-50. [PMID: 21060113 DOI: 10.1093/cercor/bhq213] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The mammalian neocortex contains an intricate processing network of multiple sensory and motor areas that allows the animal to engage in complex behaviors. These anatomically and functionally unique areas and their distinct connections arise during early development, through a process termed arealization. Both intrinsic, activity-independent and extrinsic, activity-dependent mechanisms drive arealization, much of which occurs during the areal patterning period (APP) from late embryogenesis to early postnatal life. How areal boundaries and their connections develop and change from infancy to adulthood is not known. Additionally, the adult patterns of sensory and motor ipsilateral intraneocortical connections (INCs) have not been thoroughly characterized in the mouse. In this report and its companion (I), we present the first lifespan analysis of ipsilateral INCs among multiple sensory and motor regions in mouse. We describe the neocortical expression patterns of several developmentally regulated genes that are of central importance to studies investigating the molecular regulation of arealization, from postnatal day (P) 6 to P50. In this study, we correlate the boundaries of gene expression patterns with developing areal boundaries across a lifespan, in order to better understand the nature of gene-areal relationships from early postnatal life to adulthood.
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Affiliation(s)
- Catherine A Dye
- Department of Psychology and Interdepartmental Neuroscience Program, University of California-Riverside, 900 University Avenue, Riverside, CA 92521, USA
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23
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Wimmer VC, Bruno RM, de Kock CPJ, Kuner T, Sakmann B. Dimensions of a projection column and architecture of VPM and POm axons in rat vibrissal cortex. Cereb Cortex 2010; 20:2265-76. [PMID: 20453248 PMCID: PMC2936807 DOI: 10.1093/cercor/bhq068] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
This is the first article in a series of 3 studies that investigate the anatomical determinants of thalamocortical (TC) input to excitatory neurons in a cortical column of rat primary somatosensory cortex (S1). S1 receives 2 major types of TC inputs, lemiscal and paralemniscal. Lemiscal axons arise from the ventral posteromedial nucleus (VPM) of the thalamus, whereas paralemniscal fibers originate in the posteromedial nucleus (POm). While these 2 TC projections are largely complementary in L4, overlap in other cortical layers is still a matter of debate. VPM and POm axons were specifically labeled in the same rat by virus-mediated expression of different fluorescent proteins. We show that columnar and septal projection patterns are maintained throughout most of the cortical depth with a lower degree of separation in infragranular layers, where TC axons form bands along rows. Finally, we present anatomical dimensions of "TC projection domains" for a standard column in S1.
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Affiliation(s)
- Verena C Wimmer
- Department of Cell Physiology, Max Planck Institute for Medical Research, D-69120 Heidelberg, Germany.
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24
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Quairiaux C, Sizonenko SV, Mégevand P, Michel CM, Kiss JZ. Functional deficit and recovery of developing sensorimotor networks following neonatal hypoxic-ischemic injury in the rat. Cereb Cortex 2010; 20:2080-91. [PMID: 20051355 DOI: 10.1093/cercor/bhp281] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Neonatal hypoxia-ischemia (HI) is the most important cause of brain injury in the newborn. Here we studied structural alterations and functional perturbations of developing large-scale sensorimotor cortical networks in a rat model of moderate HI at postnatal day 3 (P3). At the morphological level, HI led to a disorganized barrel pattern in the somatosensory cortex without detectable histological changes in the motor cortex. Functional effects were addressed by means of epicranial mapping of somatosensory-evoked potentials (SEPs) during the postischemic recovery period. At P10, SEPs were immature and evoked activity was almost restricted to the somatosensory and motor cortices of the contralateral hemisphere. Peak and topographic analyses of epicranial potentials revealed that responses were profoundly depressed in both sensory and motor areas of HI-lesioned animals. At the end of the postnatal period at P21, responses involved networks in both hemispheres. SEP amplitude was still depressed in the injured sensory region, but it completely recovered in the motor area. These results suggest a process of large-scale network plasticity in sensorimotor circuits after perinatal ischemic injury. The model provides new perspectives for investigating the temporal and spatial characteristics of the recovery process following HI and eventually developing therapeutic interventions.
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Affiliation(s)
- Charles Quairiaux
- Faculty of Medicine, Department of Fundamental Neurosciences, University of Geneva, 1211 Geneva, Switzerland.
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25
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Shepherd GMG. Intracortical cartography in an agranular area. Front Neurosci 2009; 3:337-43. [PMID: 20198150 PMCID: PMC2796917 DOI: 10.3389/neuro.01.030.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 07/29/2009] [Indexed: 11/23/2022] Open
Abstract
A well-defined granular layer 4 is a defining cytoarchitectonic feature associated with sensory areas of mammalian cerebral cortex, and one with hodological significance: the local axons ascending from cells in thalamorecipient layer 4 and connecting to layer 2/3 pyramidal neurons form a major feedforward excitatory interlaminar projection. Conversely, agranular cortical areas, lacking a distinct layer 4, pose a hodological conundrum: without a laminar basis for the canonical layer 4→2/3 pathway, what is the basic circuit organization? This review highlights current challenges and prospects for local-circuit electroanatomy and electrophysiology in agranular cortex, focusing on the mouse. Different lines of evidence, drawn primarily from studies of motor areas in frontal cortex in rodents, support the view that synaptic circuits in agranular cortex are organized around prominent descending excitatory layer 2/3→5 pathways targeting multiple classes of projection neurons.
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Affiliation(s)
- Gordon M G Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
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26
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Conte FF, Ribeiro PAO, Marchesini RB, Pascoal VDB, Silva JM, Oliveira AR, Gilioli R, Sbragia L, Bittencourt JC, Lopes-Cendes I. Expression Profile and Distribution of Efhc1 Gene Transcript During Rodent Brain Development. J Mol Neurosci 2009; 39:69-77. [DOI: 10.1007/s12031-009-9179-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Accepted: 01/19/2009] [Indexed: 10/21/2022]
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