1
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Carmona LM, Thomas ED, Smith K, Tasic B, Costa RM, Nelson A. Topographical and cell type-specific connectivity of rostral and caudal forelimb corticospinal neuron populations. Cell Rep 2024; 43:113993. [PMID: 38551963 PMCID: PMC11100358 DOI: 10.1016/j.celrep.2024.113993] [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: 12/01/2023] [Revised: 02/07/2024] [Accepted: 03/07/2024] [Indexed: 04/09/2024] Open
Abstract
Corticospinal neurons (CSNs) synapse directly on spinal neurons, a diverse assortment of cells with unique structural and functional properties necessary for body movements. CSNs modulating forelimb behavior fractionate into caudal forelimb area (CFA) and rostral forelimb area (RFA) motor cortical populations. Despite their prominence, the full diversity of spinal neurons targeted by CFA and RFA CSNs is uncharted. Here, we use anatomical and RNA sequencing methods to show that CSNs synapse onto a remarkably selective group of spinal cell types, favoring inhibitory populations that regulate motoneuron activity and gate sensory feedback. CFA and RFA CSNs target similar spinal neuron types, with notable exceptions that suggest that these populations differ in how they influence behavior. Finally, axon collaterals of CFA and RFA CSNs target similar brain regions yet receive highly divergent inputs. These results detail the rules of CSN connectivity throughout the brain and spinal cord for two regions critical for forelimb behavior.
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Affiliation(s)
- Lina Marcela Carmona
- Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Eric D Thomas
- Allen Institute for Brain Science, Allen Institute, Seattle, WA, USA
| | - Kimberly Smith
- Allen Institute for Brain Science, Allen Institute, Seattle, WA, USA
| | - Bosiljka Tasic
- Allen Institute for Brain Science, Allen Institute, Seattle, WA, USA
| | - Rui M Costa
- Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Allen Institute for Brain Science, Allen Institute, Seattle, WA, USA
| | - Anders Nelson
- Center for Neural Science, New York University, New York, NY 10003, USA.
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2
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García-Rosales F, Schaworonkow N, Hechavarria JC. Oscillatory Waveform Shape and Temporal Spike Correlations Differ across Bat Frontal and Auditory Cortex. J Neurosci 2024; 44:e1236232023. [PMID: 38262724 PMCID: PMC10919256 DOI: 10.1523/jneurosci.1236-23.2023] [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: 07/03/2023] [Revised: 11/01/2023] [Accepted: 11/29/2023] [Indexed: 01/25/2024] Open
Abstract
Neural oscillations are associated with diverse computations in the mammalian brain. The waveform shape of oscillatory activity measured in the cortex relates to local physiology and can be informative about aberrant or dynamically changing states. However, how waveform shape differs across distant yet functionally and anatomically related cortical regions is largely unknown. In this study, we capitalize on simultaneous recordings of local field potentials (LFPs) in the auditory and frontal cortices of awake, male Carollia perspicillata bats to examine, on a cycle-by-cycle basis, waveform shape differences across cortical regions. We find that waveform shape differs markedly in the fronto-auditory circuit even for temporally correlated rhythmic activity in comparable frequency ranges (i.e., in the delta and gamma bands) during spontaneous activity. In addition, we report consistent differences between areas in the variability of waveform shape across individual cycles. A conceptual model predicts higher spike-spike and spike-LFP correlations in regions with more asymmetric shapes, a phenomenon that was observed in the data: spike-spike and spike-LFP correlations were higher in the frontal cortex. The model suggests a relationship between waveform shape differences and differences in spike correlations across cortical areas. Altogether, these results indicate that oscillatory activity in the frontal and auditory cortex possesses distinct dynamics related to the anatomical and functional diversity of the fronto-auditory circuit.
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Affiliation(s)
- Francisco García-Rosales
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main 60528, Germany
| | - Natalie Schaworonkow
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main 60528, Germany
| | - Julio C Hechavarria
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt am Main 60438, Germany
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3
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Cieslak PE, Drabik S, Gugula A, Trenk A, Gorkowska M, Przybylska K, Szumiec L, Kreiner G, Rodriguez Parkitna J, Blasiak A. Dopamine Receptor-Expressing Neurons Are Differently Distributed throughout Layers of the Motor Cortex to Control Dexterity. eNeuro 2024; 11:ENEURO.0490-23.2023. [PMID: 38423792 DOI: 10.1523/eneuro.0490-23.2023] [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: 11/22/2023] [Revised: 12/20/2023] [Accepted: 12/29/2023] [Indexed: 03/02/2024] Open
Abstract
The motor cortex comprises the primary descending circuits for flexible control of voluntary movements and is critically involved in motor skill learning. Motor skill learning is impaired in patients with Parkinson's disease, but the precise mechanisms of motor control and skill learning are still not well understood. Here we have used transgenic mice, electrophysiology, in situ hybridization, and neural tract-tracing methods to target genetically defined cell types expressing D1 and D2 dopamine receptors in the motor cortex. We observed that putative D1 and D2 dopamine receptor-expressing neurons (D1+ and D2+, respectively) are organized in highly segregated, nonoverlapping populations. Moreover, based on ex vivo patch-clamp recordings, we showed that D1+ and D2+ cells have distinct morphological and electrophysiological properties. Finally, we observed that chemogenetic inhibition of D2+, but not D1+, neurons disrupts skilled forelimb reaching in adult mice. Overall, these results demonstrate that dopamine receptor-expressing cells in the motor cortex are highly segregated and play a specialized role in manual dexterity.
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Affiliation(s)
- Przemyslaw E Cieslak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow 30-387, Poland
| | - Sylwia Drabik
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow 30-387, Poland
| | - Anna Gugula
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow 30-387, Poland
| | - Aleksandra Trenk
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow 30-387, Poland
| | - Martyna Gorkowska
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow 30-387, Poland
| | - Kinga Przybylska
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow 30-387, Poland
| | - Lukasz Szumiec
- Department of Molecular Neuropharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Krakow 31-343, Poland
| | - Grzegorz Kreiner
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Krakow 31-343, Poland
| | - Jan Rodriguez Parkitna
- Department of Molecular Neuropharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Krakow 31-343, Poland
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow 30-387, Poland
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4
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Nieder A. Convergent Circuit Computation for Categorization in the Brains of Primates and Songbirds. Cold Spring Harb Perspect Biol 2023; 15:a041526. [PMID: 38040453 PMCID: PMC10691494 DOI: 10.1101/cshperspect.a041526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2023]
Abstract
Categorization is crucial for behavioral flexibility because it enables animals to group stimuli into meaningful classes that can easily be generalized to new circumstances. A most abstract quantitative category is set size, the number of elements in a set. This review explores how categorical number representations are realized by the operations of excitatory and inhibitory neurons in associative telencephalic microcircuits in primates and songbirds. Despite the independent evolution of the primate prefrontal cortex and the avian nidopallium caudolaterale, the neuronal computations of these associative pallial circuits show surprising correspondence. Comparing cellular functions in distantly related taxa can inform about the evolutionary principles of circuit computations for cognition in distinctly but convergently realized brain structures.
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Affiliation(s)
- Andreas Nieder
- Animal Physiology Unit, Institute of Neurobiology, University of Tübingen, 72076 Tübingen, Germany
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5
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Dura-Bernal S, Neymotin SA, Suter BA, Dacre J, Moreira JVS, Urdapilleta E, Schiemann J, Duguid I, Shepherd GMG, Lytton WW. Multiscale model of primary motor cortex circuits predicts in vivo cell-type-specific, behavioral state-dependent dynamics. Cell Rep 2023; 42:112574. [PMID: 37300831 PMCID: PMC10592234 DOI: 10.1016/j.celrep.2023.112574] [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: 04/28/2022] [Revised: 02/27/2023] [Accepted: 05/12/2023] [Indexed: 06/12/2023] Open
Abstract
Understanding cortical function requires studying multiple scales: molecular, cellular, circuit, and behavioral. We develop a multiscale, biophysically detailed model of mouse primary motor cortex (M1) with over 10,000 neurons and 30 million synapses. Neuron types, densities, spatial distributions, morphologies, biophysics, connectivity, and dendritic synapse locations are constrained by experimental data. The model includes long-range inputs from seven thalamic and cortical regions and noradrenergic inputs. Connectivity depends on cell class and cortical depth at sublaminar resolution. The model accurately predicts in vivo layer- and cell-type-specific responses (firing rates and LFP) associated with behavioral states (quiet wakefulness and movement) and experimental manipulations (noradrenaline receptor blockade and thalamus inactivation). We generate mechanistic hypotheses underlying the observed activity and analyzed low-dimensional population latent dynamics. This quantitative theoretical framework can be used to integrate and interpret M1 experimental data and sheds light on the cell-type-specific multiscale dynamics associated with several experimental conditions and behaviors.
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Affiliation(s)
- Salvador Dura-Bernal
- Department of Physiology and Pharmacology, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, USA; Center for Biomedical Imaging and Neuromodulation, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA.
| | - Samuel A Neymotin
- Center for Biomedical Imaging and Neuromodulation, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Psychiatry, Grossman School of Medicine, New York University (NYU), New York, NY, USA
| | - Benjamin A Suter
- Department of Physiology, Northwestern University, Evanston, IL, USA
| | - Joshua Dacre
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Joao V S Moreira
- Department of Physiology and Pharmacology, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, USA
| | - Eugenio Urdapilleta
- Department of Physiology and Pharmacology, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, USA
| | - Julia Schiemann
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK; Center for Integrative Physiology and Molecular Medicine, Saarland University, Saarbrücken, Germany
| | - Ian Duguid
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | | | - William W Lytton
- Department of Physiology and Pharmacology, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA; Department of Neurology, Kings County Hospital Center, Brooklyn, NY, USA
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6
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Kida H, Kawakami R, Sakai K, Otaku H, Imamura K, Han TZ, Sakimoto Y, Mitsushima D. Motor training promotes both synaptic and intrinsic plasticity of layer V pyramidal neurons in the primary motor cortex. J Physiol 2023; 601:335-353. [PMID: 36515167 DOI: 10.1113/jp283755] [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: 11/01/2022] [Accepted: 11/23/2022] [Indexed: 12/15/2022] Open
Abstract
Layer V neurons in the primary motor cortex (M1) are important for motor skill learning. Since pretreatment of either CNQX or APV in rat M1 layer V impaired rotor rod learning, we analysed training-induced synaptic plasticity by whole-cell patch-clamp technique in acute brain slices. Rats trained for 1 day showed a decrease in small inhibitory postsynaptic current (mIPSC) frequency and an increase in the paired-pulse ratio of evoked IPSCs, suggesting a transient decrease in presynaptic GABA release in the early phase. Rats trained for 2 days showed an increase in miniature excitatory postsynaptic current (mEPSC) amplitudes/frequency and elevated AMPA/NMDA ratios, suggesting a long-term strengthening of AMPA receptor-mediated excitatory synapses. Importantly, rotor rod performance in trained rats was correlated with the mean mEPSC amplitude and the frequency obtained from that animal. In current-clamp analysis, 1-day-trained rats transiently decreased the current-induced firing rate, while 2-day-trained rats returned to pre-training levels, suggesting dynamic changes in intrinsic properties. Furthermore, western blot analysis of layer V detected decreased phosphorylation of Ser408-409 in GABAA receptor β3 subunits in 1-day-trained rats, and increased phosphorylation of Ser831 in AMPA receptor GluA1 subunits in 2-day-trained rats. Finally, live-imaging analysis of Thy1-YFP transgenic mice showed that the training rapidly recruited a substantial number of spines for long-term plasticity in M1 layer V neurons. Taken together, these results indicate that motor training induces complex and diverse plasticity in M1 layer V pyramidal neurons. KEY POINTS: Here we examined motor training-induced synaptic and intrinsic plasticity of layer V pyramidal neurons in the primary motor cortex. The training reduced presynaptic GABA release in the early phase, but strengthened AMPA receptor-mediated excitatory synapses in the later phase: acquired motor performance after training correlated with the strength of excitatory synapses rather than inhibitory synapses. As to the intrinsic property, the training transiently decreased the firing rate in the early phase, but returned to pre-training levels in the later phase. Western blot analysis detected decreased phosphorylation of Ser408-409 in GABAA receptor β3 subunits in the acute phase, and increased phosphorylation of Ser831 in AMPA receptor GluA1 subunits in the later phase. Live-imaging analysis of Thy1-YFP transgenic mice showed rapid and long-term spine plasticity in M1 layer V neurons, suggesting training-induced increases in self-entropy per spine.
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Affiliation(s)
- H Kida
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - R Kawakami
- Department of Molecular Medicine for Pathogenesis, Graduate School of Medicine, Ehime University, Ehime, Japan
| | - K Sakai
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - H Otaku
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - K Imamura
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Thiri-Zin Han
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Y Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan.,The Research Institute for Time Studies, Yamaguchi University, Yamaguchi, Japan
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7
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Tocco C, Øvsthus M, Bjaalie JG, Leergaard TB, Studer M. The topography of corticopontine projections is controlled by postmitotic expression of the area-mapping gene Nr2f1. Development 2022; 149:274658. [PMID: 35262177 PMCID: PMC8959144 DOI: 10.1242/dev.200026] [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: 07/16/2021] [Accepted: 12/20/2021] [Indexed: 12/27/2022]
Abstract
Axonal projections from layer V neurons of distinct neocortical areas are topographically organized into discrete clusters within the pontine nuclei during the establishment of voluntary movements. However, the molecular determinants controlling corticopontine connectivity are insufficiently understood. Here, we show that an intrinsic cortical genetic program driven by Nr2f1 graded expression is directly implicated in the organization of corticopontine topographic mapping. Transgenic mice lacking cortical expression of Nr2f1 and exhibiting areal organization defects were used as model systems to investigate the arrangement of corticopontine projections. By combining three-dimensional digital brain atlas tools, Cre-dependent mouse lines and axonal tracing, we show that Nr2f1 expression in postmitotic neurons spatially and temporally controls somatosensory topographic projections, whereas expression in progenitor cells influences the ratio between corticopontine and corticospinal fibres passing the pontine nuclei. We conclude that cortical gradients of area-patterning genes are directly implicated in the establishment of a topographic somatotopic mapping from the cortex onto pontine nuclei. Summary: Cortical gradient expression of the area patterning gene Nr2f1 spatially and temporally controls corticopontine topographic connectivity in layer V projection neurons.
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Affiliation(s)
- Chiara Tocco
- University Côte d'Azur, CNRS, Inserm, iBV, Nice 06108, France
| | - Martin Øvsthus
- Institute of Basic Medical Sciences, University of Oslo, Oslo N-0317, Norway
| | - Jan G Bjaalie
- Institute of Basic Medical Sciences, University of Oslo, Oslo N-0317, Norway
| | - Trygve B Leergaard
- Institute of Basic Medical Sciences, University of Oslo, Oslo N-0317, Norway
| | - Michèle Studer
- University Côte d'Azur, CNRS, Inserm, iBV, Nice 06108, France
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8
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Muñoz-Castañeda R, Zingg B, Matho KS, Chen X, Wang Q, Foster NN, Li A, Narasimhan A, Hirokawa KE, Huo B, Bannerjee S, Korobkova L, Park CS, Park YG, Bienkowski MS, Chon U, Wheeler DW, Li X, Wang Y, Naeemi M, Xie P, Liu L, Kelly K, An X, Attili SM, Bowman I, Bludova A, Cetin A, Ding L, Drewes R, D'Orazi F, Elowsky C, Fischer S, Galbavy W, Gao L, Gillis J, Groblewski PA, Gou L, Hahn JD, Hatfield JT, Hintiryan H, Huang JJ, Kondo H, Kuang X, Lesnar P, Li X, Li Y, Lin M, Lo D, Mizrachi J, Mok S, Nicovich PR, Palaniswamy R, Palmer J, Qi X, Shen E, Sun YC, Tao HW, Wakemen W, Wang Y, Yao S, Yuan J, Zhan H, Zhu M, Ng L, Zhang LI, Lim BK, Hawrylycz M, Gong H, Gee JC, Kim Y, Chung K, Yang XW, Peng H, Luo Q, Mitra PP, Zador AM, Zeng H, Ascoli GA, Josh Huang Z, Osten P, Harris JA, Dong HW. Cellular anatomy of the mouse primary motor cortex. Nature 2021; 598:159-166. [PMID: 34616071 PMCID: PMC8494646 DOI: 10.1038/s41586-021-03970-w] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 08/27/2021] [Indexed: 12/24/2022]
Abstract
An essential step toward understanding brain function is to establish a structural framework with cellular resolution on which multi-scale datasets spanning molecules, cells, circuits and systems can be integrated and interpreted1. Here, as part of the collaborative Brain Initiative Cell Census Network (BICCN), we derive a comprehensive cell type-based anatomical description of one exemplar brain structure, the mouse primary motor cortex, upper limb area (MOp-ul). Using genetic and viral labelling, barcoded anatomy resolved by sequencing, single-neuron reconstruction, whole-brain imaging and cloud-based neuroinformatics tools, we delineated the MOp-ul in 3D and refined its sublaminar organization. We defined around two dozen projection neuron types in the MOp-ul and derived an input-output wiring diagram, which will facilitate future analyses of motor control circuitry across molecular, cellular and system levels. This work provides a roadmap towards a comprehensive cellular-resolution description of mammalian brain architecture.
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Affiliation(s)
| | - Brian Zingg
- UCLA Brain Research and Artificial Intelligence Nexus, Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
| | | | - Xiaoyin Chen
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Quanxin Wang
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Nicholas N Foster
- UCLA Brain Research and Artificial Intelligence Nexus, Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
| | - Anan Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan, China
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou, China
| | | | - Karla E Hirokawa
- Allen Institute for Brain Science, Seattle, WA, USA
- Cajal Neuroscience, Seattle, WA, USA
| | - Bingxing Huo
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Laura Korobkova
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
| | - Chris Sin Park
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Young-Gyun Park
- Institute for Medical Engineering and Science, Department of Chemical Engineering, Picower Institute for Learning and Memory, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Michael S Bienkowski
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine of USC, University of Southern California, Los Angeles, California, USA
| | - Uree Chon
- Department of Neural and Behavioral Sciences, College of Medicine, Penn State University, Hershey, PA, USA
| | - Diek W Wheeler
- Center for Neural Informatics, Structures and Plasticity, Bioengineering Department and Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA
| | - Xiangning Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan, China
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou, China
| | - Yun Wang
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Peng Xie
- SEU-ALLEN Joint Center, Institute for Brain and Intelligence, Southeast University, Nanjing, China
| | - Lijuan Liu
- SEU-ALLEN Joint Center, Institute for Brain and Intelligence, Southeast University, Nanjing, China
| | - Kathleen Kelly
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Xu An
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA
| | - Sarojini M Attili
- Center for Neural Informatics, Structures and Plasticity, Bioengineering Department and Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA
| | - Ian Bowman
- UCLA Brain Research and Artificial Intelligence Nexus, Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
| | | | - Ali Cetin
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Liya Ding
- SEU-ALLEN Joint Center, Institute for Brain and Intelligence, Southeast University, Nanjing, China
| | - Rhonda Drewes
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Corey Elowsky
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | | | - Lei Gao
- UCLA Brain Research and Artificial Intelligence Nexus, Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
| | - Jesse Gillis
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Lin Gou
- UCLA Brain Research and Artificial Intelligence Nexus, Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
| | - Joel D Hahn
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Joshua T Hatfield
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA
| | - Houri Hintiryan
- UCLA Brain Research and Artificial Intelligence Nexus, Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
| | - Junxiang Jason Huang
- Center for Neural Circuits and Sensory Processing Disorders, Zilkha Neurogenetics Institute (ZNI), Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Hideki Kondo
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Xiuli Kuang
- School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | | | - Xu Li
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Yaoyao Li
- School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | - Mengkuan Lin
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Darrick Lo
- UCLA Brain Research and Artificial Intelligence Nexus, Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
| | | | | | - Philip R Nicovich
- Allen Institute for Brain Science, Seattle, WA, USA
- Cajal Neuroscience, Seattle, WA, USA
| | | | - Jason Palmer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Xiaoli Qi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Elise Shen
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Yu-Chi Sun
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Huizhong W Tao
- Center for Neural Circuits and Sensory Processing Disorders, Zilkha Neurogenetics Institute (ZNI), Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - Yimin Wang
- SEU-ALLEN Joint Center, Institute for Brain and Intelligence, Southeast University, Nanjing, China
- School of Computer Engineering and Science, Shanghai University, Shanghai, China
| | - Shenqin Yao
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Jing Yuan
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan, China
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou, China
| | - Huiqing Zhan
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Muye Zhu
- UCLA Brain Research and Artificial Intelligence Nexus, Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
| | - Lydia Ng
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Li I Zhang
- Center for Neural Circuits and Sensory Processing Disorders, Zilkha Neurogenetics Institute (ZNI), Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Byung Kook Lim
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou, China
- Division of Biological Science, Neurobiology section, University of California San Diego, San Diego, CA, USA
| | | | - Hui Gong
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan, China
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou, China
| | - James C Gee
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yongsoo Kim
- Department of Neural and Behavioral Sciences, College of Medicine, Penn State University, Hershey, PA, USA
| | - Kwanghun Chung
- Institute for Medical Engineering and Science, Department of Chemical Engineering, Picower Institute for Learning and Memory, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - X William Yang
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Hanchuan Peng
- SEU-ALLEN Joint Center, Institute for Brain and Intelligence, Southeast University, Nanjing, China
| | - Qingming Luo
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan, China
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou, China
| | - Partha P Mitra
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Giorgio A Ascoli
- Center for Neural Informatics, Structures and Plasticity, Bioengineering Department and Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA.
| | - Z Josh Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA.
| | - Pavel Osten
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
| | - Julie A Harris
- Allen Institute for Brain Science, Seattle, WA, USA.
- Cajal Neuroscience, Seattle, WA, USA.
| | - Hong-Wei Dong
- UCLA Brain Research and Artificial Intelligence Nexus, Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
- USC Stevens Neuroimaging and Informatics Institute (INI), Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA.
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9
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Streffing-Hellhake P, Luft A, Hosp J. Motor Learning Induces Profound but Delayed Dendritic Plasticity in M1 Layer II/III Pyramidal Neurons. Neuroscience 2020; 442:17-28. [DOI: 10.1016/j.neuroscience.2020.06.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 10/23/2022]
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10
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McColgan P, Joubert J, Tabrizi SJ, Rees G. The human motor cortex microcircuit: insights for neurodegenerative disease. Nat Rev Neurosci 2020; 21:401-415. [PMID: 32555340 DOI: 10.1038/s41583-020-0315-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2020] [Indexed: 12/22/2022]
Abstract
The human motor cortex comprises a microcircuit of five interconnected layers with different cell types. In this Review, we use a layer-specific and cell-specific approach to integrate physiological accounts of this motor cortex microcircuit with the pathophysiology of neurodegenerative diseases affecting motor functions. In doing so we can begin to link motor microcircuit pathology to specific disease stages and clinical phenotypes. Based on microcircuit physiology, we can make future predictions of axonal loss and microcircuit dysfunction. With recent advances in high-resolution neuroimaging we can then test these predictions in humans in vivo, providing mechanistic insights into neurodegenerative disease.
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Affiliation(s)
- Peter McColgan
- Huntington's Disease Research Centre, UCL Institute of Neurology, University College London, London, UK.
| | - Julie Joubert
- Huntington's Disease Research Centre, UCL Institute of Neurology, University College London, London, UK
| | - Sarah J Tabrizi
- Huntington's Disease Research Centre, UCL Institute of Neurology, University College London, London, UK.,Dementia Research Institute at UCL, London, UK
| | - Geraint Rees
- Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, University College London, London, UK.,UCL Institute of Cognitive Neuroscience, University College London, London, UK
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11
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Yang JW, Prouvot PH, Reyes-Puerta V, Stüttgen MC, Stroh A, Luhmann HJ. Optogenetic Modulation of a Minor Fraction of Parvalbumin-Positive Interneurons Specifically Affects Spatiotemporal Dynamics of Spontaneous and Sensory-Evoked Activity in Mouse Somatosensory Cortex in Vivo. Cereb Cortex 2018; 27:5784-5803. [PMID: 29040472 PMCID: PMC5939210 DOI: 10.1093/cercor/bhx261] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Parvalbumin (PV) positive interneurons exert strong effects on the neocortical excitatory network, but it remains unclear how they impact the spatiotemporal dynamics of sensory processing in the somatosensory cortex. Here, we characterized the effects of optogenetic inhibition and activation of PV interneurons on spontaneous and sensory-evoked activity in mouse barrel cortex in vivo. Inhibiting PV interneurons led to a broad-spectrum power increase both in spontaneous and sensory-evoked activity. Whisker-evoked responses were significantly increased within 20 ms after stimulus onset during inhibition of PV interneurons, demonstrating high temporal precision of PV-shaped inhibition. Multiunit activity was strongly enhanced in neighboring cortical columns, but not at the site of transduction, supporting a central and highly specific role of PV interneurons in lateral inhibition. Inversely, activating PV interneurons drastically decreased spontaneous and whisker-evoked activity in the principal column and exerted strong lateral inhibition. Histological assessment of transduced cells combined with quantitative modeling of light distribution and spike sorting revealed that only a minor fraction (~10%) of the local PV population comprising no more than a few hundred neurons is optogenetically modulated, mediating the observed prominent and widespread effects on neocortical processing.
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Affiliation(s)
- Jenq-Wei Yang
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Pierre-Hugues Prouvot
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany.,Focus Program Translational Neuroscience, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Vicente Reyes-Puerta
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Maik C Stüttgen
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Albrecht Stroh
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany.,Focus Program Translational Neuroscience, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
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12
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Specialized Subpopulations of Deep-Layer Pyramidal Neurons in the Neocortex: Bridging Cellular Properties to Functional Consequences. J Neurosci 2018; 38:5441-5455. [PMID: 29798890 DOI: 10.1523/jneurosci.0150-18.2018] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/09/2018] [Accepted: 05/11/2018] [Indexed: 12/25/2022] Open
Abstract
Neocortical pyramidal neurons with somata in layers 5 and 6 are among the most visually striking and enigmatic neurons in the brain. These deep-layer pyramidal neurons (DLPNs) integrate a plethora of cortical and extracortical synaptic inputs along their impressive dendritic arbors. The pattern of cortical output to both local and long-distance targets is sculpted by the unique physiological properties of specific DLPN subpopulations. Here we revisit two broad DLPN subpopulations: those that send their axons within the telencephalon (intratelencephalic neurons) and those that project to additional target areas outside the telencephalon (extratelencephalic neurons). While neuroscientists across many subdisciplines have characterized the intrinsic and synaptic physiological properties of DLPN subpopulations, our increasing ability to selectively target and manipulate these output neuron subtypes advances our understanding of their distinct functional contributions. This Viewpoints article summarizes our current knowledge about DLPNs and highlights recent work elucidating the functional differences between DLPN subpopulations.
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13
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Vitrac C, Benoit-Marand M. Monoaminergic Modulation of Motor Cortex Function. Front Neural Circuits 2017; 11:72. [PMID: 29062274 PMCID: PMC5640772 DOI: 10.3389/fncir.2017.00072] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Accepted: 09/19/2017] [Indexed: 01/09/2023] Open
Abstract
Elaboration of appropriate responses to behavioral situations rests on the ability of selecting appropriate motor outcomes in accordance to specific environmental inputs. To this end, the primary motor cortex (M1) is a key structure for the control of voluntary movements and motor skills learning. Subcortical loops regulate the activity of the motor cortex and thus contribute to the selection of appropriate motor plans. Monoamines are key mediators of arousal, attention and motivation. Their firing pattern enables a direct encoding of different states thus promoting or repressing the selection of actions adapted to the behavioral context. Monoaminergic modulation of motor systems has been extensively studied in subcortical circuits. Despite evidence of converging projections of multiple neurotransmitters systems in the motor cortex pointing to a direct modulation of local circuits, their contribution to the execution and learning of motor skills is still poorly understood. Monoaminergic dysregulation leads to impaired plasticity and motor function in several neurological and psychiatric conditions, thus it is critical to better understand how monoamines modulate neural activity in the motor cortex. This review aims to provide an update of our current understanding on the monoaminergic modulation of the motor cortex with an emphasis on motor skill learning and execution under physiological conditions.
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Affiliation(s)
- Clément Vitrac
- Laboratoire de Neurosciences Expérimentales et Cliniques, INSERM U1084, Poitiers, France.,Laboratoire de Neurosciences Expérimentales et Cliniques, Université de Poitiers, Poitiers, France
| | - Marianne Benoit-Marand
- Laboratoire de Neurosciences Expérimentales et Cliniques, INSERM U1084, Poitiers, France.,Laboratoire de Neurosciences Expérimentales et Cliniques, Université de Poitiers, Poitiers, France
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14
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An Ultrastructural Study of the Thalamic Input to Layer 4 of Primary Motor and Primary Somatosensory Cortex in the Mouse. J Neurosci 2017; 37:2435-2448. [PMID: 28137974 DOI: 10.1523/jneurosci.2557-16.2017] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 01/17/2017] [Accepted: 01/19/2017] [Indexed: 12/22/2022] Open
Abstract
The traditional classification of primary motor cortex (M1) as an agranular area has been challenged recently when a functional layer 4 (L4) was reported in M1. L4 is the principal target for thalamic input in sensory areas, which raises the question of how thalamocortical synapses formed in M1 in the mouse compare with those in neighboring sensory cortex (S1). We identified thalamic boutons by their immunoreactivity for the vesicular glutamate transporter 2 (VGluT2) and performed unbiased disector counts from electron micrographs. We discovered that the thalamus contributed proportionately only half as many synapses to the local circuitry of L4 in M1 compared with S1. Furthermore, thalamic boutons in M1 targeted spiny dendrites exclusively, whereas ∼9% of synapses were formed with dendrites of smooth neurons in S1. VGluT2+ boutons in M1 were smaller and formed fewer synapses per bouton on average (1.3 vs 2.1) than those in S1, but VGluT2+ synapses in M1 were larger than in S1 (median postsynaptic density areas of 0.064 μm2 vs 0.042 μm2). In M1 and S1, thalamic synapses formed only a small fraction (12.1% and 17.2%, respectively) of all of the asymmetric synapses in L4. The functional role of the thalamic input to L4 in M1 has largely been neglected, but our data suggest that, as in S1, the thalamic input is amplified by the recurrent excitatory connections of the L4 circuits. The lack of direct thalamic input to inhibitory neurons in M1 may indicate temporal differences in the inhibitory gating in L4 of M1 versus S1.SIGNIFICANCE STATEMENT Classical interpretations of the function of primary motor cortex (M1) emphasize its lack of the granular layer 4 (L4) typical of sensory cortices. However, we show here that, like sensory cortex (S1), mouse M1 also has the canonical circuit motif of a core thalamic input to the middle cortical layer and that thalamocortical synapses form a small fraction (M1: 12%; S1: 17%) of all asymmetric synapses in L4 of both areas. Amplification of thalamic input by recurrent local circuits is thus likely to be a significant mechanism in both areas. Unlike M1, where thalamocortical boutons typically form a single synapse, thalamocortical boutons in S1 usually formed multiple synapses, which means they can be identified with high probability in the electron microscope without specific labeling.
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15
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Bhatt MB, Bowen S, Rossiter HE, Dupont-Hadwen J, Moran RJ, Friston KJ, Ward NS. Computational modelling of movement-related beta-oscillatory dynamics in human motor cortex. Neuroimage 2016; 133:224-232. [PMID: 26956910 PMCID: PMC4907685 DOI: 10.1016/j.neuroimage.2016.02.078] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/25/2016] [Accepted: 02/29/2016] [Indexed: 12/19/2022] Open
Abstract
Oscillatory activity in the beta range, in human primary motor cortex (M1), shows interesting dynamics that are tied to behaviour and change systematically in disease. To investigate the pathophysiology underlying these changes, we must first understand how changes in beta activity are caused in healthy subjects. We therefore adapted a canonical (repeatable) microcircuit model used in dynamic causal modelling (DCM) previously used to model induced responses in visual cortex. We adapted this model to accommodate cytoarchitectural differences between visual and motor cortex. Using biologically plausible connections, we used Bayesian model selection to identify the best model of measured MEG data from 11 young healthy participants, performing a simple handgrip task. We found that the canonical M1 model had substantially more model evidence than the generic canonical microcircuit model when explaining measured MEG data. The canonical M1 model reproduced measured dynamics in humans at rest, in a manner consistent with equivalent studies performed in mice. Furthermore, the changes in excitability (self-inhibition) necessary to explain beta suppression during handgrip were consistent with the attenuation of sensory precision implied by predictive coding. These results establish the face validity of a model that can be used to explore the laminar interactions that underlie beta-oscillatory dynamics in humans in vivo. Our canonical M1 model may be useful for characterising the synaptic mechanisms that mediate pathophysiological beta dynamics associated with movement disorders, such as stroke or Parkinson's disease. This work aims to bridge the gap in understanding between neuronal oscillations measured with MEG and laminar interactions within motor cortex. We adapted a cortical microcircuit model used in sensory DCM studies to build a plausible model of laminar interactions in primary motor cortex. The proposed M1 model showed significantly more model evidence in explaining MEG data from M1 in humans than the inherited model. We replicated the in vitro finding of a dominant pathway from superficial to deep cortical layers at rest, providing face validity for our method. We show novel characterisation of laminar interactions underpinning beta-oscillatory dynamics within M1 during volitional movement in humans.
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Affiliation(s)
- Mrudul B Bhatt
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.
| | - Stephanie Bowen
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Holly E Rossiter
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Joshua Dupont-Hadwen
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Rosalyn J Moran
- Virginia Tech Carilion Research Institute and Bradley Department of Electrical & Computer Engineering, Roanoke, VA, USA
| | - Karl J Friston
- The Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, UK
| | - Nick S Ward
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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16
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Nocjar C, Alex KD, Sonneborn A, Abbas AI, Roth BL, Pehek EA. Serotonin-2C and -2a receptor co-expression on cells in the rat medial prefrontal cortex. Neuroscience 2015; 297:22-37. [PMID: 25818050 PMCID: PMC4595040 DOI: 10.1016/j.neuroscience.2015.03.050] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 03/20/2015] [Accepted: 03/20/2015] [Indexed: 11/28/2022]
Abstract
Neural function within the medial prefrontal cortex (mPFC) regulates normal cognition, attention and impulse control, implicating neuroregulatory abnormalities within this region in mental dysfunction related to schizophrenia, depression and drug abuse. Both serotonin-2A (5-HT2A) and -2C (5-HT2C) receptors are known to be important in neuropsychiatric drug action and are distributed throughout the mPFC. However, their interactive role in serotonergic cortical regulation is poorly understood. While the main signal transduction mechanism for both receptors is stimulation of phosphoinositide production, they can have opposite effects downstream. 5-HT2A versus 5-HT2C receptor activation oppositely regulates behavior and can oppositely affect neurochemical release within the mPFC. These distinct receptor effects could be caused by their differential cellular distribution within the cortex and/or other areas. It is known that both receptors are located on GABAergic and pyramidal cells within the mPFC, but it is not clear whether they are expressed on the same or different cells. The present work employed immunofluorescence with confocal microscopy to examine this in layers V-VI of the prelimbic mPFC. The majority of GABA cells in the deep prelimbic mPFC expressed 5-HT2C receptor immunoreactivity. Furthermore, most cells expressing 5-HT2C receptor immunoreactivity notably co-expressed 5-HT2A receptors. However, 27% of 5-HT2C receptor immunoreactive cells were not GABAergic, indicating that a population of prelimbic pyramidal projection cells could express the 5-HT2C receptor. Indeed, some cells with 5-HT2C and 5-HT2A receptor co-labeling had a pyramidal shape and were expressed in the typical layered fashion of pyramidal cells. This indirectly demonstrates that 5-HT2C and 5-HT2A receptors may be commonly co-expressed on GABAergic cells within the deep layers of the prelimbic mPFC and perhaps co-localized on a small population of local pyramidal projection cells. Thus a complex interplay of cortical 5-HT2A and 5-HT2C receptor mechanisms exists, which if altered, could modulate efferent brain systems implicated in mental illness.
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Affiliation(s)
- C Nocjar
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Psychiatry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - K D Alex
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Neurosciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - A Sonneborn
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA.
| | - A I Abbas
- Department of Psychiatry, Columbia University, New York, NY 10032, USA; Division of Integrative Neuroscience, New York State Psychiatric Institute, New York, NY 10032, USA.
| | - B L Roth
- Department of Pharmacology, University of North Carolina-Chapel Hill School of Medicine, 120 Mason Farm Road, 4072 Genetic Medicine Building, Campus Box 7365, Chapel Hill, NC 27599-7365, USA.
| | - E A Pehek
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Neurosciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Department of Psychiatry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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17
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Jiang L, O'Leary C, Kim HA, Parish CL, Massalas J, Waddington JL, Ehrlich ME, Schütz G, Gantois I, Lawrence AJ, Drago J. Motor and behavioral phenotype in conditional mutants with targeted ablation of cortical D1 dopamine receptor-expressing cells. Neurobiol Dis 2015; 76:137-158. [PMID: 25684539 DOI: 10.1016/j.nbd.2015.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 01/14/2015] [Accepted: 02/05/2015] [Indexed: 10/24/2022] Open
Abstract
D1-dopamine receptors (Drd1a) are highly expressed in the deep layers of the cerebral cortex and the striatum. A number of human diseases such as Huntington disease and schizophrenia are known to have cortical pathology involving dopamine receptor expressing neurons. To illuminate their functional role, we exploited a Cre/Lox molecular paradigm to generate Emx-1(tox) MUT mice, a transgenic line in which cortical Drd1a-expressing pyramidal neurons were selectively ablated. Emx-1(tox) MUT mice displayed prominent forelimb dystonia, hyperkinesia, ataxia on rotarod testing, heightened anxiety-like behavior, and age-dependent abnormalities in a test of social interaction. The latter occurred in the context of normal working memory on testing in the Y-maze and for novel object recognition. Some motor and behavioral abnormalities in Emx-1(tox) MUT mice overlapped with those in CamKIIα(tox) MUT transgenic mice, a line in which both striatal and cortical Drd1a-expressing cells were ablated. Although Emx-1(tox) MUT mice had normal striatal anatomy, both Emx-1(tox) MUT and CamKIIα(tox) MUT mice displayed selective neuronal loss in cortical layers V and VI. This study shows that loss of cortical Drd1a-expressing cells is sufficient to produce deficits in multiple motor and behavioral domains, independent of striatal mechanisms. Primary cortical changes in the D1 dopamine receptor compartment are therefore likely to model a number of core clinical features in disorders such as Huntington disease and schizophrenia.
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Affiliation(s)
- Luning Jiang
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia; St Vincent's Hospital, Melbourne, Victoria, Australia
| | - Claire O'Leary
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia; Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Hyun Ah Kim
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Clare L Parish
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Jim Massalas
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - John L Waddington
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Michelle E Ehrlich
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA
| | - Günter Schütz
- Deutsches Krebsforschungszentrum, Heidelberg, Germany
| | - Ilse Gantois
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Andrew J Lawrence
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - John Drago
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia; St Vincent's Hospital, Melbourne, Victoria, Australia.
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18
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Murakami M, Mainen ZF. Preparing and selecting actions with neural populations: toward cortical circuit mechanisms. Curr Opin Neurobiol 2015; 33:40-6. [PMID: 25658753 DOI: 10.1016/j.conb.2015.01.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 01/09/2015] [Indexed: 12/20/2022]
Abstract
How the brain selects one action among multiple alternatives is a central question of neuroscience. An influential model is that action preparation and selection arise from subthreshold activation of the very neurons encoding the action. Recent work, however, shows a much greater diversity of decision-related and action-related signals coexisting with other signals in populations of motor and parietal cortical neurons. We discuss how such distributed signals might be decoded by biologically plausible mechanisms. We also discuss how neurons within cortical circuits might interact with each other during action selection and preparation and how recurrent network models can help to reveal dynamical principles underlying cortical computation.
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Affiliation(s)
- Masayoshi Murakami
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Zachary F Mainen
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal.
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19
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Harris KD, Shepherd GMG. The neocortical circuit: themes and variations. Nat Neurosci 2015; 18:170-81. [PMID: 25622573 PMCID: PMC4889215 DOI: 10.1038/nn.3917] [Citation(s) in RCA: 634] [Impact Index Per Article: 70.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 12/04/2014] [Indexed: 12/12/2022]
Abstract
Similarities in neocortical circuit organization across areas and species suggest a common strategy to process diverse types of information, including sensation from diverse modalities, motor control and higher cognitive processes. Cortical neurons belong to a small number of main classes. The properties of these classes, including their local and long-range connectivity, developmental history, gene expression, intrinsic physiology and in vivo activity patterns, are remarkably similar across areas. Each class contains subclasses; for a rapidly growing number of these, conserved patterns of input and output connections are also becoming evident. The ensemble of circuit connections constitutes a basic circuit pattern that appears to be repeated across neocortical areas, with area- and species-specific modifications. Such 'serially homologous' organization may adapt individual neocortical regions to the type of information each must process.
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Affiliation(s)
- Kenneth D. Harris
- UCL Institute of Neurology and UCL Department of Neuroscience, Physiology, and Pharmacology, University College London, UK
| | - Gordon M. G. Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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20
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Hedrick T, Waters J. Acetylcholine excites neocortical pyramidal neurons via nicotinic receptors. J Neurophysiol 2015; 113:2195-209. [PMID: 25589590 DOI: 10.1152/jn.00716.2014] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 01/13/2015] [Indexed: 11/22/2022] Open
Abstract
The neuromodulator acetylcholine (ACh) shapes neocortical function during sensory perception, motor control, arousal, attention, learning, and memory. Here we investigate the mechanisms by which ACh affects neocortical pyramidal neurons in adult mice. Stimulation of cholinergic axons activated muscarinic and nicotinic ACh receptors on pyramidal neurons in all cortical layers and in multiple cortical areas. Nicotinic receptor activation evoked short-latency, depolarizing postsynaptic potentials (PSPs) in many pyramidal neurons. Nicotinic receptor-mediated PSPs promoted spiking of pyramidal neurons. The duration of the increase in spiking was membrane potential dependent, with nicotinic receptor activation triggering persistent spiking lasting many seconds in neurons close to threshold. Persistent spiking was blocked by intracellular BAPTA, indicating that nicotinic ACh receptor activation evoked persistent spiking via a long-lasting calcium-activated depolarizing current. We compared nicotinic PSPs in primary motor cortex (M1), prefrontal cortex (PFC), and visual cortex. The laminar pattern of nicotinic excitation was not uniform but was broadly similar across areas, with stronger modulation in deep than superficial layers. Superimposed on this broad pattern were local differences, with nicotinic PSPs being particularly large and common in layer 5 of M1 but not layer 5 of PFC or primary visual cortex (V1). Hence, in addition to modulating the excitability of pyramidal neurons in all layers via muscarinic receptors, synaptically released ACh preferentially increases the activity of deep-layer neocortical pyramidal neurons via nicotinic receptors, thereby adding laminar selectivity to the widespread enhancement of excitability mediated by muscarinic ACh receptors.
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Affiliation(s)
- Tristan Hedrick
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Jack Waters
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Yamawaki N, Borges K, Suter BA, Harris KD, Shepherd GMG. A genuine layer 4 in motor cortex with prototypical synaptic circuit connectivity. eLife 2014; 3:e05422. [PMID: 25525751 PMCID: PMC4290446 DOI: 10.7554/elife.05422] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/18/2014] [Indexed: 12/28/2022] Open
Abstract
The motor cortex (M1) is classically considered an agranular area, lacking a distinct layer 4 (L4). Here, we tested the idea that M1, despite lacking a cytoarchitecturally visible L4, nevertheless possesses its equivalent in the form of excitatory neurons with input–output circuits like those of the L4 neurons in sensory areas. Consistent with this idea, we found that neurons located in a thin laminar zone at the L3/5A border in the forelimb area of mouse M1 have multiple L4-like synaptic connections: excitatory input from thalamus, largely unidirectional excitatory outputs to L2/3 pyramidal neurons, and relatively weak long-range corticocortical inputs and outputs. M1-L4 neurons were electrophysiologically diverse but morphologically uniform, with pyramidal-type dendritic arbors and locally ramifying axons, including branches extending into L2/3. Our findings therefore identify pyramidal neurons in M1 with the expected prototypical circuit properties of excitatory L4 neurons, and question the traditional assumption that motor cortex lacks this layer. DOI:http://dx.doi.org/10.7554/eLife.05422.001 In 1909, a German scientist called Korbinian Brodmann published the first map of the outer layer of the human brain. After staining neurons with a dye and studying the structures of the cells and how they were organized, he realized that he could divide the cortex into 43 numbered regions. Most Brodmann areas can be divided into a number of horizontal layers, with layer 1 being closest to the surface of the brain. Neurons in the different layers form distinct sets of connections, and the relative thickness of the layers has implications for the function carried out by that area. It is thought, for example, that the motor cortex does not have a layer 4, which suggests that the neural circuitry that controls movement differs from that in charge of vision, hearing, and other functions. Yamawaki et al. now challenge this view by providing multiple lines of evidence for the existence of layer 4 in the motor cortex in mice. Neurons at the border between layer 3 and layer 5A in the motor cortex possess many of the same properties as the neurons in layer 4 in sensory cortex. In particular, they receive inputs from a brain region called the thalamus, and send outputs to neurons in layers 2 and 3. Yamawaki et al. go on to characterize some of the properties of the neurons in the putative layer 4 of the motor cortex, finding that they do not look like the specialized ‘stellate’ cells that are found in some other areas of the cortex. Instead, they resemble the ‘pyramidal’ type of neuron that is found in all layers and areas of the cortex. The discovery that the motor cortex is more similar in its circuit connections to other area of the cortex than previously thought has important implications for our understanding of this region of the brain. DOI:http://dx.doi.org/10.7554/eLife.05422.002
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Affiliation(s)
- Naoki Yamawaki
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Katharine Borges
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Benjamin A Suter
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Kenneth D Harris
- Institute of Neurology, University College London, London, United Kingdom
| | - Gordon M G Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States
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Abstract
Hemodynamic signals are widely used to infer neural activity in the brain. We tested the hypothesis that hemodynamic signals faithfully report neural activity during voluntary behaviors by measuring cerebral blood volume (CBV) and neural activity in the somatosensory cortex and frontal cortex of head-fixed mice during locomotion. Locomotion induced a large and robust increase in firing rate and gamma-band (40-100 Hz) power in the local field potential in the limb representations in somatosensory cortex, and was accompanied by increases in CBV, demonstrating that hemodynamic signals are coupled with neural activity in this region. However, in the frontal cortex, CBV did not change during locomotion, but firing rate and gamma-band power both increased, indicating a decoupling of neural activity from the hemodynamic signal. These results show that hemodynamic signals are not faithful indicators of the mean neural activity in the frontal cortex during locomotion; thus, the results from fMRI and other hemodynamic imaging methodologies for studying neural processes must be interpreted with caution.
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Abstract
Magnetic resonance imaging can now provide human brain images of structure, function, and connectivity with isotropic voxels smaller than one millimeter, and thus much smaller than the cortical thickness. This resolution, achievable in a scan time of less than 1 h, enables visualization of myeloarchitectural layer structure, intracortical variations in functional activity--recorded in changes in blood oxygenation level dependent signal or cerebral blood volume CBV--and intracortical axonal orientational structure via diffusion-weighted magnetic resonance imaging. While recent improvements in radiofrequency receiver coils now enable excellent image data to be obtained at 3T, scanning at the ultra-high field of 7 T offers further gains in signal-to-noise ratio and speed of image acquisition, with a structural image resolution of about 300 μm. These improvements throw into sharp question the strategies that have become conventional for the analysis of functional imaging data, especially the practice of spatial smoothing of raw functional data before further analysis. Creation of a native cortical map for each human subject that provides a reliable individual parcellation into cortical areas related to Brodmann Areas enables a strikingly different approach to functional image analysis. This proposed approach involves surface registration of the cortices of groups of subjects using maps of the longitudinal relaxation time T1 as an index of myelination, and methods for inferring statistical significance that do not entail spatial smoothing. The outcome should be a far more precise comparison of like-with-like cortical areas across subjects, with the potential to greatly increase experimental power, to discriminate activity in neighboring cortical areas, and to enable correlation of function and connectivity with specific cytoarchitecture. Such analyses should enable a far more convincing modeling of brain mechanisms than current graph-based methods that require gross over-simplification of brain activity patterns in order to be computationally tractable.
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Affiliation(s)
- Robert Turner
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences , Leipzig, Germany
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24
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Alfano C, Magrinelli E, Harb K, Studer M. The nuclear receptors COUP-TF: a long-lasting experience in forebrain assembly. Cell Mol Life Sci 2014; 71:43-62. [PMID: 23525662 PMCID: PMC11114017 DOI: 10.1007/s00018-013-1320-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Revised: 02/14/2013] [Accepted: 03/04/2013] [Indexed: 12/16/2022]
Abstract
Chicken ovalbumin upstream promoter transcription factors (COUP-TFs) are nuclear receptors belonging to the superfamily of the steroid/thyroid hormone receptors. Members of this family are internalized to the nucleus both in a ligand-dependent or -independent manner and act as strong transcriptional regulators by binding to the DNA of their target genes. COUP-TFs are defined as orphan receptors, since ligands regulating their activity have not so far been identified. From the very beginning of metazoan evolution, these molecules have been involved in various key events during embryonic development and organogenesis. In this review, we will mainly focus on their function during development and maturation of the central nervous system, which has been well characterized in various animal classes ranging from ctenophores to mammals. We will start by introducing the current knowledge on COUP-TF mechanisms of action and then focus our discussion on the crucial processes underlying forebrain ontogenesis, with special emphasis on mammalian development. Finally, the conserved roles of COUP-TFs along phylogenesis will be highlighted, and some hypotheses, worth exploring in future years to gain more insight into the mechanisms controlled by these factors, will be proposed.
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Affiliation(s)
- Christian Alfano
- Institute of Biology Valrose, iBV, UMR INSERM1091/CNRS7277/UNS, 06108 Nice, France
- University of Nice-Sophia Antipolis, UFR Sciences, 06108 Nice, France
| | - Elia Magrinelli
- Institute of Biology Valrose, iBV, UMR INSERM1091/CNRS7277/UNS, 06108 Nice, France
- University of Nice-Sophia Antipolis, UFR Sciences, 06108 Nice, France
| | - Kawssar Harb
- Institute of Biology Valrose, iBV, UMR INSERM1091/CNRS7277/UNS, 06108 Nice, France
- University of Nice-Sophia Antipolis, UFR Sciences, 06108 Nice, France
| | - Michèle Studer
- Institute of Biology Valrose, iBV, UMR INSERM1091/CNRS7277/UNS, 06108 Nice, France
- University of Nice-Sophia Antipolis, UFR Sciences, 06108 Nice, France
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25
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van Aerde KI, Feldmeyer D. Morphological and physiological characterization of pyramidal neuron subtypes in rat medial prefrontal cortex. ACTA ACUST UNITED AC 2013; 25:788-805. [PMID: 24108807 DOI: 10.1093/cercor/bht278] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The medial prefrontal cortex (mPFC) has been implicated in cognitive and executive processes including decision making, working memory and behavioral flexibility. Cortical processing depends on the interaction between distinct neuronal cell types in different cortical layers. To better understand cortical processing in the rat mPFC, we studied the diversity of pyramidal neurons using in vitro whole-cell patch clamp recordings and biocytin staining of neurons, followed by morphological analysis. Using unsupervised cluster analysis for the objective grouping of neurons, we identified more than 10 different pyramidal subtypes spread across the different cortical layers. Layer 2 pyramidal neurons possessed a unique morphology with wide apical dendritic field spans and a narrow basal field span. Layer 3 contained the only subtype that showed a burst of action potentials upon current injection. Layer 5 pyramidal neurons showed the largest voltage sags. Finally, pyramidal neurons in layer 6 (L6) showed a great variety in their morphology with 39% of L6 neurons possessing tall apical dendrites that extend into layer 1. Future experiments on the functional role of the mPFC should take into account the great diversity of pyramidal neurons.
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Affiliation(s)
- Karlijn I van Aerde
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine, INM-2, D-52425 Jülich, Germany Current address: Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Science, 1105 BA Amsterdam, The Netherlands
| | - Dirk Feldmeyer
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine, INM-2, D-52425 Jülich, Germany Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Medical School, D-52074 Aachen, Germany Jülich Aachen Research Alliance, Translational Brain Medicine (JARA-Brain), D-52074 Aachen, Germany
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26
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Tsubo Y, Isomura Y, Fukai T. Neural dynamics and information representation in microcircuits of motor cortex. Front Neural Circuits 2013; 7:85. [PMID: 23653596 PMCID: PMC3642500 DOI: 10.3389/fncir.2013.00085] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 04/16/2013] [Indexed: 11/28/2022] Open
Abstract
The brain has to analyze and respond to external events that can change rapidly from time to time, suggesting that information processing by the brain may be essentially dynamic rather than static. The dynamical features of neural computation are of significant importance in motor cortex that governs the process of movement generation and learning. In this paper, we discuss these features based primarily on our recent findings on neural dynamics and information coding in the microcircuit of rat motor cortex. In fact, cortical neurons show a variety of dynamical behavior from rhythmic activity in various frequency bands to highly irregular spike firing. Of particular interest are the similarity and dissimilarity of the neuronal response properties in different layers of motor cortex. By conducting electrophysiological recordings in slice preparation, we report the phase response curves (PRCs) of neurons in different cortical layers to demonstrate their layer-dependent synchronization properties. We then study how motor cortex recruits task-related neurons in different layers for voluntary arm movements by simultaneous juxtacellular and multiunit recordings from behaving rats. The results suggest an interesting difference in the spectrum of functional activity between the superficial and deep layers. Furthermore, the task-related activities recorded from various layers exhibited power law distributions of inter-spike intervals (ISIs), in contrast to a general belief that ISIs obey Poisson or Gamma distributions in cortical neurons. We present a theoretical argument that this power law of in vivo neurons may represent the maximization of the entropy of firing rate with limited energy consumption of spike generation. Though further studies are required to fully clarify the functional implications of this coding principle, it may shed new light on information representations by neurons and circuits in motor cortex.
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Affiliation(s)
- Yasuhiro Tsubo
- Laboratory for Neural Circuit Theory, RIKEN Brain Science Institute Wako, Saitama, Japan
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27
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Alfano C, Studer M. Neocortical arealization: evolution, mechanisms, and open questions. Dev Neurobiol 2013; 73:411-47. [PMID: 23239642 DOI: 10.1002/dneu.22067] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 11/03/2012] [Accepted: 12/06/2012] [Indexed: 12/13/2022]
Abstract
The mammalian neocortex is a structure with no equals in the vertebrates and is the seat of the highest cerebral functions, such as thoughts and consciousness. It is radially organized into six layers and tangentially subdivided into functional areas deputed to the elaboration of sensory information, association between different stimuli, and selection and triggering of voluntary movements. The process subdividing the neocortical field into several functional areas is called "arealization". Each area has its own cytoarchitecture, connectivity, and peculiar functions. In the last century, several neuroscientists have investigated areal structure and the mechanisms that have led during evolution to the rising of the neocortex and its organization. The extreme conservation in the positioning and wiring of neocortical areas among different mammalian families suggests a conserved genetic program orchestrating neocortical patterning. However, the impressive plasticity of the neocortex, which is able to rewire and reorganize areal structures and connectivity after impairments of sensory pathways, argues for a more complex scenario. Indeed, even if genetics and molecular biology helped in identifying several genes involved in the arealization process, the logic underlying the neocortical bauplan is still beyond our comprehension. In this review, we will introduce the present knowledge and hypotheses on the ontogenesis and evolution of neocortical areas. Then, we will focus our attention on some open issues, which are still unresolved, and discuss some recent studies that might open new directions to be explored in the next few years.
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Affiliation(s)
- Christian Alfano
- Institute of Biology Valrose, iBV, UMR INSERM1091/CNRS7277/UNS, Nice, F-06108, France.
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28
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Reiner A. You are who you talk with--a commentary on Dugas-Ford et al. PNAS, 2012. BRAIN, BEHAVIOR AND EVOLUTION 2013; 81:146-9. [PMID: 23549088 DOI: 10.1159/000348281] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Anton Reiner
- University of Tennessee Health Sciences Center, Department of Anatomy and Neurobiology, Memphis, TN 38163, USA.
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29
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Aracri P, Amadeo A, Pasini ME, Fascio U, Becchetti A. Regulation of glutamate release by heteromeric nicotinic receptors in layer V of the secondary motor region (Fr2) in the dorsomedial shoulder of prefrontal cortex in mouse. Synapse 2013; 67:338-57. [PMID: 23424068 DOI: 10.1002/syn.21655] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Accepted: 02/15/2013] [Indexed: 12/24/2022]
Abstract
We studied how nicotinic acetylcholine receptors (nAChRs) regulate glutamate release in the secondary motor area (Fr2) of the dorsomedial murine prefrontal cortex, in the presence of steady agonist levels. Fr2 mediates response to behavioral situations that require immediate attention and is a candidate for generating seizures in the frontal epilepsies caused by mutant nAChRs. Morphological analysis showed a peculiar chemoarchitecture and laminar distribution of pyramidal cells and interneurons. Tonic application of 5 µM nicotine on Layer V pyramidal neurons strongly increased the frequency of spontaneous glutamatergic excitatory postsynaptic currents. The effect was inhibited by 1 µM dihydro-β-erythroidine (which blocks α4-containing nAChRs) but not by 10 nM methyllicaconitine (which blocks α7-containing receptors). Excitatory postsynaptic currents s were also stimulated by 5-iodo-3-[2(S)-azetidinylmethoxy]pyridine, selective for β2-containing receptors, in a dihydro-β-erythroidine -sensitive way. We next studied the association of α4 with different populations of glutamatergic terminals, by using as markers the vesicular glutamate transporter type (VGLUT) 1 for corticocortical synapses and VGLUT2 for thalamocortical projecting fibers. Immunoblots showed higher expression of α4 in Fr2, as compared with the somatosensory cortex. Immunofluorescence showed intense VGLUT1 staining throughout the cortical layers, whereas VGLUT2 immunoreactivity displayed a more distinct laminar distribution. In Layer V, colocalization of α4 nAChR subunit with both VGLUT1 and VGLUT2 was considerably stronger in Fr2 than in somatosensory cortex. Thus, in Fr2, α4β2 nAChRs are expressed in both intrinsic and extrinsic glutamatergic terminals and give a major contribution to control glutamate release in Layer V, in the presence of tonic agonist levels.
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Affiliation(s)
- Patrizia Aracri
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano 20126, Italy
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30
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Harrison TC, Murphy TH. Towards a circuit mechanism for movement tuning in motor cortex. Front Neural Circuits 2013; 6:127. [PMID: 23346050 PMCID: PMC3548231 DOI: 10.3389/fncir.2012.00127] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 12/31/2012] [Indexed: 02/01/2023] Open
Abstract
The firing rates of neurons in primate motor cortex have been related to multiple parameters of voluntary movement. This finding has been corroborated by stimulation-based studies that have mapped complex movements in rodent and primate motor cortex. However, it has been difficult to link the movement tuning of a neuron with its role within the cortical microcircuit. In sensory cortex, neuronal tuning is largely established by afferents delivering information from tuned receptors in the periphery. Motor cortex, which lacks the granular input layer, may be better understood by analyzing its efferent projections. As a primary source of cortical output, layer 5 neurons represent an ideal starting point for this line of experimentation. It is in these deep output layers that movements can most effectively be evoked by intracortical microstimulation and recordings can obtain the most useful signals for the control of motor prostheses. Studies focused on layer 5 output neurons have revealed that projection identity is a fundamental property related to the laminar position, receptive field and ion channel complement of these cells. Given the variety of brain areas targeted by layer 5 output neurons, knowledge of a neuron's downstream connectivity may provide insight into its movement tuning. Future experiments that relate motor behavior to the activity of neurons with a known projection identity will yield a more detailed understanding of the function of cortical microcircuits.
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Affiliation(s)
- Thomas C Harrison
- Department of Psychiatry, University of British Columbia Vancouver, BC, Canada
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31
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Hajnik T, Tóth A, Détári L. Characteristic changes in the slow cortical waves after a 6-h sleep deprivation in rat. Brain Res 2013; 1501:1-11. [PMID: 23333371 DOI: 10.1016/j.brainres.2012.12.047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/14/2012] [Accepted: 12/24/2012] [Indexed: 10/27/2022]
Abstract
Sleep deprivation is followed by an increase in EEG delta power during recovery sleep indicating an increased sleep propensity. Delta waves mostly reflect the rhythmic recurring of generalized hyperpolarizations (DOWN state) in cortical neurons causing large, deep-positive waves in the LFP. Enhancement of delta power in recovery sleep can be the consequence of either the more frequent occurrence, or the higher amplitude caused by higher synchrony, or the longer duration of these DOWN states. In the present experiments, we examined these possibilities and found the strongest increase in the incidence of slow deep positive LFP waves (slow waves) following sleep deprivation indicating enhancement of DOWN state inducing and/or weakening of UP state maintaining processes. The strong decrease in multiunit activity during slow waves was preceded by a gradual buildup of activity. The significant correlation between these changes both in control and recovery recordings indicate that excitation might determine the subsequent drop in activity. Increased sensitivity of cortical neurons to excitation might offer an explanation for this observation. Current-source-density analysis indicated in our experiments that the first sources during DOWN states appeared in layer III-IV. Activation was then displaced to layer V. In the motor cortex, both corticocortical and thalamocortical fibers terminate in layer III that provides a strong feedforward excitation to layer V. As propagation of facilitatory signals through cortical layers is downwardly biased, disfacilitation might also follow this pattern. Sleep deprivation caused only quantitative differences in the sink-source patterns, indicating that existing processes were enhanced by sleep deprivation.
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Affiliation(s)
- Tünde Hajnik
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary.
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32
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Hooks BM, Mao T, Gutnisky DA, Yamawaki N, Svoboda K, Shepherd GMG. Organization of cortical and thalamic input to pyramidal neurons in mouse motor cortex. J Neurosci 2013; 33:748-60. [PMID: 23303952 PMCID: PMC3710148 DOI: 10.1523/jneurosci.4338-12.2013] [Citation(s) in RCA: 235] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/06/2012] [Accepted: 11/14/2012] [Indexed: 11/21/2022] Open
Abstract
Determining how long-range synaptic inputs engage pyramidal neurons in primary motor cortex (M1) is important for understanding circuit mechanisms involved in regulating movement. We used channelrhodopsin-2-assisted circuit mapping to characterize the long-range excitatory synaptic connections made by multiple cortical and thalamic areas onto pyramidal neurons in mouse vibrissal motor cortex (vM1). Each projection innervated vM1 pyramidal neurons with a unique laminar profile. Collectively, the profiles for different sources of input partially overlapped and spanned all cortical layers. Specifically, orbital cortex (OC) inputs primarily targeted neurons in L6. Secondary motor cortex (M2) inputs excited neurons mainly in L5B, including pyramidal tract neurons. In contrast, thalamocortical inputs from anterior motor-related thalamic regions, including VA/VL (ventral anterior thalamic nucleus/ventrolateral thalamic nucleus), targeted neurons in L2/3 through L5B, but avoided L6. Inputs from posterior sensory-related thalamic areas, including POm (posterior thalamic nuclear group), targeted neurons only in the upper layers (L2/3 and L5A), similar to inputs from somatosensory (barrel) cortex. Our results show that long-range excitatory inputs target vM1 pyramidal neurons in a layer-specific manner. Inputs from sensory-related cortical and thalamic areas preferentially target the upper-layer pyramidal neurons in vM1. In contrast, inputs from OC and M2, areas associated with volitional and cognitive aspects of movements, bypass local circuitry and have direct monosynaptic access to neurons projecting to brainstem and thalamus.
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Affiliation(s)
- Bryan M. Hooks
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, and
| | - Tianyi Mao
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, and
| | - Diego A. Gutnisky
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, and
| | - Naoki Yamawaki
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Karel Svoboda
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, and
| | - Gordon M. G. Shepherd
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, and
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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33
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Sheets PL, Suter BA, Kiritani T, Chan CS, Surmeier DJ, Shepherd GMG. Corticospinal-specific HCN expression in mouse motor cortex: I(h)-dependent synaptic integration as a candidate microcircuit mechanism involved in motor control. J Neurophysiol 2011; 106:2216-31. [PMID: 21795621 PMCID: PMC3214092 DOI: 10.1152/jn.00232.2011] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 07/24/2011] [Indexed: 02/06/2023] Open
Abstract
Motor cortex is a key brain center involved in motor control in rodents and other mammals, but specific intracortical mechanisms at the microcircuit level are largely unknown. Neuronal expression of hyperpolarization-activated current (I(h)) is cell class specific throughout the nervous system, but in neocortex, where pyramidal neurons are classified in various ways, a systematic pattern of expression has not been identified. We tested whether I(h) is differentially expressed among projection classes of pyramidal neurons in mouse motor cortex. I(h) expression was high in corticospinal neurons and low in corticostriatal and corticocortical neurons, a pattern mirrored by mRNA levels for HCN1 and Trip8b subunits. Optical mapping experiments showed that I(h) attenuated glutamatergic responses evoked across the apical and basal dendritic arbors of corticospinal but not corticostriatal neurons. Due to I(h), corticospinal neurons resonated, with a broad peak at ∼4 Hz, and were selectively modulated by α-adrenergic stimulation. I(h) reduced the summation of short trains of artificial excitatory postsynaptic potentials (EPSPs) injected at the soma, and similar effects were observed for short trains of actual EPSPs evoked from layer 2/3 neurons. I(h) narrowed the coincidence detection window for EPSPs arriving from separate layer 2/3 inputs, indicating that the dampening effect of I(h) extended to spatially disperse inputs. To test the role of corticospinal I(h) in transforming EPSPs into action potentials, we transfected layer 2/3 pyramidal neurons with channelrhodopsin-2 and used rapid photostimulation across multiple sites to synaptically drive spiking activity in postsynaptic neurons. Blocking I(h) increased layer 2/3-driven spiking in corticospinal but not corticostriatal neurons. Our results imply that I(h)-dependent synaptic integration in corticospinal neurons constitutes an intracortical control mechanism, regulating the efficacy with which local activity in motor cortex is transferred to downstream circuits in the spinal cord. We speculate that modulation of I(h) in corticospinal neurons could provide a microcircuit-level mechanism involved in translating action planning into action execution.
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Affiliation(s)
- Patrick L Sheets
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA.
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34
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Qiu S, Anderson CT, Levitt P, Shepherd GMG. Circuit-specific intracortical hyperconnectivity in mice with deletion of the autism-associated Met receptor tyrosine kinase. J Neurosci 2011; 31:5855-64. [PMID: 21490227 PMCID: PMC3086026 DOI: 10.1523/jneurosci.6569-10.2011] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/04/2011] [Accepted: 02/17/2011] [Indexed: 01/04/2023] Open
Abstract
Local hyperconnectivity in the neocortex is a hypothesized pathophysiological state in autism spectrum disorder (ASD). MET, a receptor tyrosine kinase that regulates dendrite and spine morphogenesis, has been established as a risk gene for ASD. Here, we analyzed the synaptic circuit organization of identified pyramidal neurons in the anterior frontal cortex of mice with a dorsal pallium-derived, conditional knock-out (cKO) of Met. Synaptic mapping by glutamate uncaging identified layer 2/3 as the main source of local excitatory input to layer 5 projection neurons in controls. In both cKO and heterozygotes, this pathway was stronger by a factor of approximately 2. This increase was both sublayer and projection-class specific, restricted to corticostriatal neurons in upper layer 5B and not neighboring corticopontine neurons. Paired recordings in cKO slices demonstrated increased unitary connectivity. We propose that excitatory hyperconnectivity in specific neocortical microcircuits constitutes a physiological basis for Met-mediated ASD risk.
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Affiliation(s)
- Shenfeng Qiu
- Zilkha Neurogenetics Institute, Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90089, and
| | - Charles T. Anderson
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Pat Levitt
- Zilkha Neurogenetics Institute, Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90089, and
| | - Gordon M. G. Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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35
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Weber ET, Andrade R. Htr2a Gene and 5-HT(2A) Receptor Expression in the Cerebral Cortex Studied Using Genetically Modified Mice. Front Neurosci 2010; 4. [PMID: 20802802 PMCID: PMC2928707 DOI: 10.3389/fnins.2010.00036] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 05/12/2010] [Indexed: 11/26/2022] Open
Abstract
Serotonin receptors of the 5-HT2A subtype are robustly expressed in the cerebral cortex where they have been implicated in the pathophysiology and therapeutics of mental disorders and the actions of hallucinogens. Much less is known, however, about the specific cell types expressing 5-HT2A receptors in cortex. In the current study we use immunohistochemical and electrophysiological approaches in genetically modified mice to address the expression of the Htr2a gene and 5-HT2A receptors in cortex. We first use an EGFP-expressing BAC transgenic mice and identify three main Htr2A gene expressing neuronal populations in cortex. The largest of these cell populations corresponds to layer V pyramidal cells of the anterior cortex, followed by GABAergic interneurons of the middle layers, and non-pyramidal cells of the subplate/Layer VIb. We then use 5-HT2A receptor knockout mice to identify an antibody capable of localizing 5-HT2A receptors in brain and use it to map these receptors. We find strong laminar expression of 5-HT2A receptors in cortex, especially along a diffuse band overlaying layer Va. This band exhibits a strong anteroposterior gradient that closely matches the localization of Htr2A expressing pyramidal cells of layer V. Finally we use electrophysiological and immunohistochemical approaches to show that most, but not all, GABAergic interneurons of the middle layers are parvalbumin expressing Fast-spiking interneurons and that these cells are depolarized and excited by serotonin, most likely through the activation of 5-HT2A receptors. These results clarify and extend our understanding of the cellular distribution of 5-HT2A receptors in the cerebral cortex.
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Affiliation(s)
- Elaine T Weber
- Department of Pharmacology, Wayne State University School of Medicine Detroit, MI, USA
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Anderson CT, Sheets PL, Kiritani T, Shepherd GMG. Sublayer-specific microcircuits of corticospinal and corticostriatal neurons in motor cortex. Nat Neurosci 2010; 13:739-44. [PMID: 20436481 PMCID: PMC2876193 DOI: 10.1038/nn.2538] [Citation(s) in RCA: 193] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 03/26/2010] [Indexed: 12/14/2022]
Abstract
The mammalian motor system is organized around distinct subcortical subsystems, suggesting that the intracortical circuits immediately upstream of spinal cord and basal ganglia might be functionally differentiated as well. We found that the main excitatory pathway in mouse motor cortex, layer 2/3-->5, is fractionated into distinct pathways targeting corticospinal and corticostriatal neurons, which are involved in motor control. However, connections were selective for neurons in certain sublayers: corticospinal neurons in upper layer 5B and corticostriatal neurons in lower 5A. A simple structural combinatorial principle accounts for this highly specific functional circuit architecture: potential connectivity is established by neuronal sublayer positioning and actual connectivity in this framework is determined by long-range axonal projection targets. Thus, intracortical circuits of these pyramidal neurons are specified not only by their long-range axonal targets or their layer or sublayer positions, but by both, in specific combinations.
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Affiliation(s)
- Charles T Anderson
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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Wood L, Shepherd GMG. Synaptic circuit abnormalities of motor-frontal layer 2/3 pyramidal neurons in a mutant mouse model of Rett syndrome. Neurobiol Dis 2010; 38:281-7. [PMID: 20138994 PMCID: PMC2854239 DOI: 10.1016/j.nbd.2010.01.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 01/22/2010] [Accepted: 01/27/2010] [Indexed: 10/19/2022] Open
Abstract
Motor and cognitive functions are severely impaired in Rett syndrome (RTT). Here, we examined local synaptic circuits of layer 2/3 (L2/3) pyramidal neurons in motor-frontal cortex of male hemizygous MeCP2-null mice at 3 to 4weeks of age. We mapped local excitatory input to L2/3 neurons using glutamate uncaging and laser scanning photostimulation, and compared synaptic input maps recorded from MeCP2-null and wild type (WT) mice. Local excitatory input was significantly reduced in the mutants. The strongest phenotype was observed for lateral (horizontal, intralaminar) inputs, that is, L2/3-->2/3 inputs, which showed a large reduction in MeCP2(-/y) animals. Neither the amount of local inhibitory input to these L2/3 pyramidal neurons nor their intrinsic electrophysiological properties differed by genotype. Our findings provide further evidence that excitatory networks are selectively reduced in RTT. We discuss our findings in the context of recently published parallel studies using selective MeCP2 knockdown in individual L2/3 neurons.
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Affiliation(s)
- Lydia Wood
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
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