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Beninger J, Rossbroich J, Tóth K, Naud R. Functional subtypes of synaptic dynamics in mouse and human. Cell Rep 2024; 43:113785. [PMID: 38363673 DOI: 10.1016/j.celrep.2024.113785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 12/08/2023] [Accepted: 01/27/2024] [Indexed: 02/18/2024] Open
Abstract
Synapses preferentially respond to particular temporal patterns of activity with a large degree of heterogeneity that is informally or tacitly separated into classes. Yet, the precise number and properties of such classes are unclear. Do they exist on a continuum and, if so, when is it appropriate to divide that continuum into functional regions? In a large dataset of glutamatergic cortical connections, we perform model-based characterization to infer the number and characteristics of functionally distinct subtypes of synaptic dynamics. In rodent data, we find five clusters that partially converge with transgenic-associated subtypes. Strikingly, the application of the same clustering method in human data infers a highly similar number of clusters, supportive of stable clustering. This nuanced dictionary of functional subtypes shapes the heterogeneity of cortical synaptic dynamics and provides a lens into the basic motifs of information transmission in the brain.
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Affiliation(s)
- John Beninger
- Center for Neural Dynamics and Artificial Intelligence, University of Ottawa, Ottawa, ON K1H 8M5, Canada; uOttawa Brain and Mind Research Institute, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Julian Rossbroich
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland; Faculty of Science, University of Basel, Basel, Switzerland
| | - Katalin Tóth
- Center for Neural Dynamics and Artificial Intelligence, University of Ottawa, Ottawa, ON K1H 8M5, Canada; uOttawa Brain and Mind Research Institute, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Richard Naud
- Center for Neural Dynamics and Artificial Intelligence, University of Ottawa, Ottawa, ON K1H 8M5, Canada; uOttawa Brain and Mind Research Institute, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Department of Physics, University of Ottawa, Ottawa, ON K1H 8M5, Canada.
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2
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Buchholz MO, Gastone Guilabert A, Ehret B, Schuhknecht GFP. How synaptic strength, short-term plasticity, and input synchrony contribute to neuronal spike output. PLoS Comput Biol 2023; 19:e1011046. [PMID: 37068099 PMCID: PMC10153727 DOI: 10.1371/journal.pcbi.1011046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 05/02/2023] [Accepted: 03/24/2023] [Indexed: 04/18/2023] Open
Abstract
Neurons integrate from thousands of synapses whose strengths span an order of magnitude. Intriguingly, in mouse neocortex, the few 'strong' synapses are formed between similarly tuned cells, suggesting they determine spiking output. This raises the question of how other computational primitives, including 'background' activity from the many 'weak' synapses, short-term plasticity, and temporal factors contribute to spiking. We used paired recordings and extracellular stimulation experiments to map excitatory postsynaptic potential (EPSP) amplitudes and paired-pulse ratios of synaptic connections formed between pyramidal neurons in layer 2/3 (L2/3) of barrel cortex. While net short-term plasticity was weak, strong synaptic connections were exclusively depressing. Importantly, we found no evidence for clustering of synaptic properties on individual neurons. Instead, EPSPs and paired-pulse ratios of connections converging onto the same cells spanned the full range observed across L2/3, which critically constrains theoretical models of cortical filtering. To investigate how different computational primitives of synaptic information processing interact to shape spiking, we developed a computational model of a pyramidal neuron in the excitatory L2/3 circuitry, which was constrained by our experiments and published in vivo data. We found that strong synapses were substantially depressed during ongoing activation and their ability to evoke correlated spiking primarily depended on their high temporal synchrony and high firing rates observed in vivo. However, despite this depression, their larger EPSP amplitudes strongly amplified information transfer and responsiveness. Thus, our results contribute to a nuanced framework of how cortical neurons exploit synergies between temporal coding, synaptic properties, and noise to transform synaptic inputs into spikes.
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Affiliation(s)
- Moritz O Buchholz
- Institute of Neuroinformatics, University of Zürich and ETH Zürich Zürich, Switzerland
| | | | - Benjamin Ehret
- Institute of Neuroinformatics, University of Zürich and ETH Zürich Zürich, Switzerland
| | - Gregor F P Schuhknecht
- Institute of Neuroinformatics, University of Zürich and ETH Zürich Zürich, Switzerland
- Department of Molecular and Cellular Biology, Harvard University Cambridge, Massachusetts, United States of America
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3
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Jetti SK, Crane AB, Akbergenova Y, Aponte-Santiago NA, Cunningham KL, Whittaker CA, Littleton JT. Molecular Logic of Synaptic Diversity Between Drosophila Tonic and Phasic Motoneurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.17.524447. [PMID: 36711745 PMCID: PMC9882338 DOI: 10.1101/2023.01.17.524447] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Although neuronal subtypes display unique synaptic organization and function, the underlying transcriptional differences that establish these features is poorly understood. To identify molecular pathways that contribute to synaptic diversity, single neuron PatchSeq RNA profiling was performed on Drosophila tonic and phasic glutamatergic motoneurons. Tonic motoneurons form weaker facilitating synapses onto single muscles, while phasic motoneurons form stronger depressing synapses onto multiple muscles. Super-resolution microscopy and in vivo imaging demonstrated synaptic active zones in phasic motoneurons are more compact and display enhanced Ca 2+ influx compared to their tonic counterparts. Genetic analysis identified unique synaptic properties that mapped onto gene expression differences for several cellular pathways, including distinct signaling ligands, post-translational modifications and intracellular Ca 2+ buffers. These findings provide insights into how unique transcriptomes drive functional and morphological differences between neuronal subtypes.
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Affiliation(s)
- Suresh K Jetti
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Andrés B Crane
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Yulia Akbergenova
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Nicole A Aponte-Santiago
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Karen L Cunningham
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Charles A Whittaker
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
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4
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Barri A, Wiechert MT, Jazayeri M, DiGregorio DA. Synaptic basis of a sub-second representation of time in a neural circuit model. Nat Commun 2022; 13:7902. [PMID: 36550115 PMCID: PMC9780315 DOI: 10.1038/s41467-022-35395-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022] Open
Abstract
Temporal sequences of neural activity are essential for driving well-timed behaviors, but the underlying cellular and circuit mechanisms remain elusive. We leveraged the well-defined architecture of the cerebellum, a brain region known to support temporally precise actions, to explore theoretically whether the experimentally observed diversity of short-term synaptic plasticity (STP) at the input layer could generate neural dynamics sufficient for sub-second temporal learning. A cerebellar circuit model equipped with dynamic synapses produced a diverse set of transient granule cell firing patterns that provided a temporal basis set for learning precisely timed pauses in Purkinje cell activity during simulated delay eyelid conditioning and Bayesian interval estimation. The learning performance across time intervals was influenced by the temporal bandwidth of the temporal basis, which was determined by the input layer synaptic properties. The ubiquity of STP throughout the brain positions it as a general, tunable cellular mechanism for sculpting neural dynamics and fine-tuning behavior.
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Affiliation(s)
- A. Barri
- grid.508487.60000 0004 7885 7602Institut Pasteur, Université Paris Cité, Synapse and Circuit Dynamics Laboratory, CNRS UMR 3571 Paris, France
| | - M. T. Wiechert
- grid.508487.60000 0004 7885 7602Institut Pasteur, Université Paris Cité, Synapse and Circuit Dynamics Laboratory, CNRS UMR 3571 Paris, France
| | - M. Jazayeri
- grid.116068.80000 0001 2341 2786McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA USA ,grid.116068.80000 0001 2341 2786Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA USA
| | - D. A. DiGregorio
- grid.508487.60000 0004 7885 7602Institut Pasteur, Université Paris Cité, Synapse and Circuit Dynamics Laboratory, CNRS UMR 3571 Paris, France
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5
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Lautz JD, Tsegay KB, Zhu Z, Gniffke EP, Welsh JP, Smith SEP. Synaptic protein interaction networks encode experience by assuming stimulus-specific and brain-region-specific states. Cell Rep 2021; 37:110076. [PMID: 34852231 PMCID: PMC8722361 DOI: 10.1016/j.celrep.2021.110076] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 10/01/2021] [Accepted: 11/09/2021] [Indexed: 11/02/2022] Open
Abstract
A core network of widely expressed proteins within the glutamatergic post-synapse mediates activity-dependent synaptic plasticity throughout the brain, but the specific proteomic composition of synapses differs between brain regions. Here, we address the question, how does proteomic composition affect activity-dependent protein-protein interaction networks (PINs) downstream of synaptic activity? Using quantitative multiplex co-immunoprecipitation, we compare the PIN response of in vivo or ex vivo neurons derived from different brain regions to activation by different agonists or different forms of eyeblink conditioning. We report that PINs discriminate between incoming stimuli using differential kinetics of overlapping and non-overlapping PIN parameters. Further, these "molecular logic rules" differ by brain region. We conclude that although the PIN of the glutamatergic post-synapse is expressed widely throughout the brain, its activity-dependent dynamics show remarkable stimulus-specific and brain-region-specific diversity. This diversity may help explain the challenges in developing molecule-specific drug therapies for neurological disorders.
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Affiliation(s)
- Jonathan D Lautz
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Kaleb B Tsegay
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Zhiyi Zhu
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Edward P Gniffke
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - John P Welsh
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Stephen E P Smith
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA; Graduate Program in Neuroscience, University of Washington, Seattle, WA, USA.
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6
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Adibi M, Lampl I. Sensory Adaptation in the Whisker-Mediated Tactile System: Physiology, Theory, and Function. Front Neurosci 2021; 15:770011. [PMID: 34776857 PMCID: PMC8586522 DOI: 10.3389/fnins.2021.770011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 09/30/2021] [Indexed: 12/03/2022] Open
Abstract
In the natural environment, organisms are constantly exposed to a continuous stream of sensory input. The dynamics of sensory input changes with organism's behaviour and environmental context. The contextual variations may induce >100-fold change in the parameters of the stimulation that an animal experiences. Thus, it is vital for the organism to adapt to the new diet of stimulation. The response properties of neurons, in turn, dynamically adjust to the prevailing properties of sensory stimulation, a process known as "neuronal adaptation." Neuronal adaptation is a ubiquitous phenomenon across all sensory modalities and occurs at different stages of processing from periphery to cortex. In spite of the wealth of research on contextual modulation and neuronal adaptation in visual and auditory systems, the neuronal and computational basis of sensory adaptation in somatosensory system is less understood. Here, we summarise the recent finding and views about the neuronal adaptation in the rodent whisker-mediated tactile system and further summarise the functional effect of neuronal adaptation on the response dynamics and encoding efficiency of neurons at single cell and population levels along the whisker-mediated touch system in rodents. Based on direct and indirect pieces of evidence presented here, we suggest sensory adaptation provides context-dependent functional mechanisms for noise reduction in sensory processing, salience processing and deviant stimulus detection, shift between integration and coincidence detection, band-pass frequency filtering, adjusting neuronal receptive fields, enhancing neural coding and improving discriminability around adapting stimuli, energy conservation, and disambiguating encoding of principal features of tactile stimuli.
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Affiliation(s)
- Mehdi Adibi
- Department of Physiology and Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
- Department of Neuroscience and Padova Neuroscience Center (PNC), University of Padova, Padova, Italy
| | - Ilan Lampl
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
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7
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Bale MR, Bitzidou M, Giusto E, Kinghorn P, Maravall M. Sequence Learning Induces Selectivity to Multiple Task Parameters in Mouse Somatosensory Cortex. Curr Biol 2021; 31:473-485.e5. [PMID: 33186553 PMCID: PMC7883307 DOI: 10.1016/j.cub.2020.10.059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 09/01/2020] [Accepted: 10/20/2020] [Indexed: 11/20/2022]
Abstract
Sequential temporal ordering and patterning are key features of natural signals, used by the brain to decode stimuli and perceive them as sensory objects. To explore how cortical neuronal activity underpins sequence discrimination, we developed a task in which mice distinguished between tactile "word" sequences constructed from distinct vibrations delivered to the whiskers, assembled in different orders. Animals licked to report the presence of the target sequence. Mice could respond to the earliest possible cues allowing discrimination, effectively solving the task as a "detection of change" problem, but enhanced their performance when responding later. Optogenetic inactivation showed that the somatosensory cortex was necessary for sequence discrimination. Two-photon imaging in layer 2/3 of the primary somatosensory "barrel" cortex (S1bf) revealed that, in well-trained animals, neurons had heterogeneous selectivity to multiple task variables including not just sensory input but also the animal's action decision and the trial outcome (presence or absence of the predicted reward). Many neurons were activated preceding goal-directed licking, thus reflecting the animal's learned action in response to the target sequence; these neurons were found as soon as mice learned to associate the rewarded sequence with licking. In contrast, learning evoked smaller changes in sensory response tuning: neurons responding to stimulus features were found in naive mice, and training did not generate neurons with enhanced temporal integration or categorical responses. Therefore, in S1bf, sequence learning results in neurons whose activity reflects the learned association between target sequence and licking rather than a refined representation of sensory features.
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Affiliation(s)
- Michael R Bale
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK
| | - Malamati Bitzidou
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK
| | - Elena Giusto
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK
| | - Paul Kinghorn
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK
| | - Miguel Maravall
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK.
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8
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Torres JJ, Baroni F, Latorre R, Varona P. Temporal discrimination from the interaction between dynamic synapses and intrinsic subthreshold oscillations. Neurocomputing 2020. [DOI: 10.1016/j.neucom.2020.07.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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Distinct Nanoscale Calcium Channel and Synaptic Vesicle Topographies Contribute to the Diversity of Synaptic Function. Neuron 2019; 104:693-710.e9. [PMID: 31558350 DOI: 10.1016/j.neuron.2019.08.014] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 05/31/2019] [Accepted: 08/08/2019] [Indexed: 12/22/2022]
Abstract
The nanoscale topographical arrangement of voltage-gated calcium channels (VGCC) and synaptic vesicles (SVs) determines synaptic strength and plasticity, but whether distinct spatial distributions underpin diversity of synaptic function is unknown. We performed single bouton Ca2+ imaging, Ca2+ chelator competition, immunogold electron microscopic (EM) localization of VGCCs and the active zone (AZ) protein Munc13-1, at two cerebellar synapses. Unexpectedly, we found that weak synapses exhibited 3-fold more VGCCs than strong synapses, while the coupling distance was 5-fold longer. Reaction-diffusion modeling could explain both functional and structural data with two strikingly different nanotopographical motifs: strong synapses are composed of SVs that are tightly coupled (∼10 nm) to VGCC clusters, whereas at weak synapses VGCCs were excluded from the vicinity (∼50 nm) of docked vesicles. The distinct VGCC-SV topographical motifs also confer differential sensitivity to neuromodulation. Thus, VGCC-SV arrangements are not canonical, and their diversity could underlie functional heterogeneity across CNS synapses.
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10
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van Gils T, Tiesinga PHE, Englitz B, Martens MB. Sensitivity to Stimulus Irregularity Is Inherent in Neural Networks. Neural Comput 2019; 31:1789-1824. [PMID: 31335294 DOI: 10.1162/neco_a_01215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Behavior is controlled by complex neural networks in which neurons process thousands of inputs. However, even short spike trains evoked in a single cortical neuron were demonstrated to be sufficient to influence behavior in vivo. Specifically, irregular sequences of interspike intervals (ISIs) had a more reliable influence on behavior despite their resemblance to stochastic activity. Similarly, irregular tactile stimulation led to higher rates of behavioral responses. In this study, we identify the mechanisms enabling this sensitivity to stimulus irregularity (SSI) on the neuronal and network levels using simulated spiking neural networks. Matching in vivo experiments, we find that irregular stimulation elicits more detectable network events (bursts) than regular stimulation. Dissecting the stimuli, we identify short ISIs-occurring more frequently in irregular stimulations-as the main drivers of SSI rather than complex irregularity per se. In addition, we find that short-term plasticity modulates SSI. We subsequently eliminate the different mechanisms in turn to assess their role in generating SSI. Removing inhibitory interneurons, we find that SSI is retained, suggesting that SSI is not dependent on inhibition. Removing recurrency, we find that SSI is retained due to the ability of individual neurons to integrate activity over short timescales ("cell memory"). Removing single-neuron dynamics, we find that SSI is retained based on the short-term retention of activity within the recurrent network structure ("network memory"). Finally, using a further simplified probabilistic model, we find that local network structure is not required for SSI. Hence, SSI is identified as a general property that we hypothesize to be ubiquitous in neural networks with different structures and biophysical properties. Irregular sequences contain shorter ISIs, which are the main drivers underlying SSI. The experimentally observed SSI should thus generalize to other systems, suggesting a functional role for irregular activity in cortex.
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Affiliation(s)
- Teun van Gils
- Department of Neuroinformatics and Department of Neurophysiology, Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, Gelderland, The Netherlands
| | - Paul H E Tiesinga
- Department of Neuroinformatics, Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, Gelderland, The Netherlands
| | - Bernhard Englitz
- Department of Neurophysiology, Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, Gelderland, The Netherlands
| | - Marijn B Martens
- Department of Neuroinformatics, Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, Gelderland, The Netherlands
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11
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Fekete A, Nakamura Y, Yang YM, Herlitze S, Mark MD, DiGregorio DA, Wang LY. Underpinning heterogeneity in synaptic transmission by presynaptic ensembles of distinct morphological modules. Nat Commun 2019; 10:826. [PMID: 30778063 PMCID: PMC6379440 DOI: 10.1038/s41467-019-08452-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 12/28/2018] [Indexed: 11/09/2022] Open
Abstract
Synaptic heterogeneity is widely observed but its underpinnings remain elusive. We addressed this issue using mature calyx of Held synapses whose numbers of bouton-like swellings on stalks of the nerve terminals inversely correlate with release probability (Pr). We examined presynaptic Ca2+ currents and transients, topology of fluorescently tagged knock-in Ca2+ channels, and Ca2+ channel-synaptic vesicle (SV) coupling distance using Ca2+ chelator and inhibitor of septin cytomatrix in morphologically diverse synapses. We found that larger clusters of Ca2+ channels with tighter coupling distance to SVs elevate Pr in stalks, while smaller clusters with looser coupling distance lower Pr in swellings. Septin is a molecular determinant of the differences in coupling distance. Supported by numerical simulations, we propose that varying the ensemble of two morphological modules containing distinct Ca2+ channel-SV topographies diversifies Pr in the terminal, thereby establishing a morpho-functional continuum that expands the coding capacity within a single synapse population.
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Affiliation(s)
- Adam Fekete
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Department of Physiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Yukihiro Nakamura
- Department of Pharmacology, Jikei University School of Medicine, Nishishinbashi, Minato-ku, Tokyo, 1058461, Japan
| | - Yi-Mei Yang
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Department of Physiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Department of Biomedical Sciences, University of Minnesota Medical School, 1035 University Drive, Duluth, MN, 55812, USA
| | - Stefan Herlitze
- Department of General Zoology and Neurobiology, Ruhr-University Bochum, Universitätsstrasse 150, D-44780, Bochum, Germany
| | - Melanie D Mark
- Department of General Zoology and Neurobiology, Ruhr-University Bochum, Universitätsstrasse 150, D-44780, Bochum, Germany
| | - David A DiGregorio
- Unit of Dynamic Neuronal Imaging, Institut Pasteur, 25 rue du Dr Roux, 75724, Paris Cedex 15, France
- Centre National de la Recherche Scientifique (CNRS), UMR 3571, Genes, Synapses and Cognition, Institut Pasteur, 25 rue du Dr Roux, 75724, Paris Cedex 15, France
| | - Lu-Yang Wang
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada.
- Department of Physiology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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12
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Motanis H, Seay MJ, Buonomano DV. Short-Term Synaptic Plasticity as a Mechanism for Sensory Timing. Trends Neurosci 2018; 41:701-711. [PMID: 30274605 DOI: 10.1016/j.tins.2018.08.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/18/2018] [Accepted: 08/01/2018] [Indexed: 11/25/2022]
Abstract
The ability to detect time intervals and temporal patterns is critical to some of the most fundamental computations the brain performs, including the ability to communicate and appraise a dynamically changing environment. Many of these computations take place on the scale of tens to hundreds of milliseconds. Electrophysiological evidence shows that some neurons respond selectively to duration, interval, rate, or order. Because the time constants of many time-varying neural and synaptic properties, including short-term synaptic plasticity (STP), are also in the range of tens to hundreds of milliseconds, they are strong candidates to underlie the formation of temporally selective neurons. Neurophysiological studies indicate that STP is indeed one of the mechanisms that contributes to temporal selectivity, and computational models demonstrate that neurons embedded in local microcircuits exhibit temporal selectivity if their synapses undergo STP. Converging evidence suggests that some forms of temporal selectivity emerge from the dynamic changes in the balance of excitation and inhibition imposed by STP.
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Affiliation(s)
- Helen Motanis
- Integrative Center for Learning & Memory, Departments of Neurobiology and Psychology, UCLA, Los Angeles, CA, 90095, USA; These authors contributed equally to the paper
| | - Michael J Seay
- Integrative Center for Learning & Memory, Departments of Neurobiology and Psychology, UCLA, Los Angeles, CA, 90095, USA; These authors contributed equally to the paper
| | - Dean V Buonomano
- Integrative Center for Learning & Memory, Departments of Neurobiology and Psychology, UCLA, Los Angeles, CA, 90095, USA.
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13
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Kheradpezhouh E, Adibi M, Arabzadeh E. Response dynamics of rat barrel cortex neurons to repeated sensory stimulation. Sci Rep 2017; 7:11445. [PMID: 28904406 PMCID: PMC5597595 DOI: 10.1038/s41598-017-11477-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 08/24/2017] [Indexed: 11/25/2022] Open
Abstract
Neuronal adaptation is a common feature observed at various stages of sensory processing. Here, we quantified the time course of adaptation in rat somatosensory cortex. Under urethane anesthesia, we juxta-cellularly recorded single neurons (n = 147) while applying a series of whisker deflections at various frequencies (2-32 Hz). For ~90% of neurons, the response per unit of time decreased with frequency. The degree of adaptation increased along the train of deflections and was strongest at the highest frequency. However, a subset of neurons showed facilitation producing higher responses to subsequent deflections. The response latency to consecutive deflections increased both for neurons that exhibited adaptation and for those that exhibited response facilitation. Histological reconstruction of neurons (n = 45) did not reveal a systematic relationship between adaptation profiles and cell types. In addition to the periodic stimuli, we applied a temporally irregular train of deflections with a mean frequency of 8 Hz. For 70% of neurons, the response to the irregular stimulus was greater than that of the 8 Hz regular. This increased response to irregular stimulation was positively correlated with the degree of adaptation. Altogether, our findings demonstrate high levels of diversity among cortical neurons, with a proportion of neurons showing facilitation at specific temporal intervals.
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Affiliation(s)
- Ehsan Kheradpezhouh
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia.
- Australian Research Council Centre of Excellence for Integrative Brain Function, Australian National University Node, Canberra, ACT, Australia.
| | - Mehdi Adibi
- University of New South Wales, UNSW, Sydney, NSW, Australia
- International School for Advanced Studies - SISSA, Trieste, Italy
| | - Ehsan Arabzadeh
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, Australian National University Node, Canberra, ACT, Australia
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14
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Gleizes M, Perrier SP, Fonta C, Nowak LG. Prominent facilitation at beta and gamma frequency range revealed with physiological calcium concentration in adult mouse piriform cortex in vitro. PLoS One 2017; 12:e0183246. [PMID: 28820903 PMCID: PMC5562311 DOI: 10.1371/journal.pone.0183246] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 08/01/2017] [Indexed: 12/25/2022] Open
Abstract
Neuronal activity is characterized by a diversity of oscillatory phenomena that are associated with multiple behavioral and cognitive processes, yet the functional consequences of these oscillations are not fully understood. Our aim was to determine whether and how these different oscillatory activities affect short-term synaptic plasticity (STP), using the olfactory system as a model. In response to odorant stimuli, the olfactory bulb displays a slow breathing rhythm as well as beta and gamma oscillations. Since the firing of olfactory bulb projecting neurons is phase-locked with beta and gamma oscillations, structures downstream from the olfactory bulb should be driven preferentially at these frequencies. We examined STP exhibited by olfactory bulb inputs in slices of adult mouse piriform cortex maintained in vitro in an in vivo-like ACSF (calcium concentration: 1.1 mM). We replaced the presynaptic neuronal firing rate by repeated electrical stimulation (frequency between 3.125 and 100 Hz) applied to the lateral olfactory tract. Our results revealed a considerable enhancement of postsynaptic response amplitude for stimulation frequencies in the beta and gamma range. A phenomenological model of STP fitted to the data suggests that the experimental results can be explained by the interplay between three mechanisms: a short-term facilitation mechanism (time constant ≈160 msec), and two short-term depression mechanisms (recovery time constants <20 msec and ≈140 msec). Increasing calcium concentration (2.2 mM) resulted in an increase in the time constant of facilitation and in a strengthening of the slowest depression mechanism. As a result, response enhancement was reduced and its peak shifted toward the low beta and alpha ranges while depression became predominant in the gamma band. Using environmental conditions corresponding to those that prevail in vivo, our study shows that STP in the lateral olfactory tract to layer Ia synapse allows amplification of olfactory bulb inputs at beta and gamma frequencies.
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Affiliation(s)
- Marie Gleizes
- Centre de Recherche Cerveau et Cognition, Université de Toulouse, Toulouse, France
- Unité Mixte de Recherche 5549, Centre National de la Recherche Scientifique, Toulouse, France
| | - Simon P. Perrier
- Centre de Recherche Cerveau et Cognition, Université de Toulouse, Toulouse, France
- Unité Mixte de Recherche 5549, Centre National de la Recherche Scientifique, Toulouse, France
| | - Caroline Fonta
- Centre de Recherche Cerveau et Cognition, Université de Toulouse, Toulouse, France
- Unité Mixte de Recherche 5549, Centre National de la Recherche Scientifique, Toulouse, France
| | - Lionel G. Nowak
- Centre de Recherche Cerveau et Cognition, Université de Toulouse, Toulouse, France
- Unité Mixte de Recherche 5549, Centre National de la Recherche Scientifique, Toulouse, France
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15
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Pitas A, Albarracín AL, Molano-Mazón M, Maravall M. Variable Temporal Integration of Stimulus Patterns in the Mouse Barrel Cortex. Cereb Cortex 2017; 27:1758-1764. [PMID: 26838770 DOI: 10.1093/cercor/bhw006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Making sense of the world requires distinguishing temporal patterns and sequences lasting hundreds of milliseconds or more. How cortical circuits integrate over time to represent specific sensory sequences remains elusive. Here we assessed whether neurons in the barrel cortex (BC) integrate information about temporal patterns of whisker movements. We performed cell-attached recordings in anesthetized mice while delivering whisker deflections at variable intervals and compared the information carried by neurons about the latest interstimulus interval (reflecting sensitivity to instantaneous frequency) and earlier intervals (reflecting integration over timescales up to several hundred milliseconds). Neurons carried more information about the latest interval than earlier ones. The amount of temporal integration varied with neuronal responsiveness and with the cortical depth of the recording site, that is, with laminar location. A subset of neurons in the upper layers displayed the strongest integration. Highly responsive neurons in the deeper layers encoded the latest interval but integrated particularly weakly. Under these conditions, BC neurons act primarily as encoders of current stimulation parameters; however, our results suggest that temporal integration over hundreds of milliseconds can emerge in some neurons within BC.
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Affiliation(s)
- Anna Pitas
- Instituto de Neurociencias de Alicante, CSIC and Universidad Miguel Hernández, 03550 Sant Joan d'Alacant, Spain.,Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, UK
| | - Ana Lía Albarracín
- Instituto de Neurociencias de Alicante, CSIC and Universidad Miguel Hernández, 03550 Sant Joan d'Alacant, Spain.,Laboratorio de Medios e Interfases, Departamento de Bioingeniería, Universidad Nacional de Tucumán-Consejo Superior de Investigaciones Científicas y Técnicas, Tucumán, Argentina
| | - Manuel Molano-Mazón
- Instituto de Neurociencias de Alicante, CSIC and Universidad Miguel Hernández, 03550 Sant Joan d'Alacant, Spain.,Laboratory of Neural Computation, Istituto Italiano di Tecnologia Rovereto, 38068 Rovereto, Italy
| | - Miguel Maravall
- Instituto de Neurociencias de Alicante, CSIC and Universidad Miguel Hernández, 03550 Sant Joan d'Alacant, Spain.,Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, UK
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16
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Liu B, Macellaio MV, Osborne LC. Efficient sensory cortical coding optimizes pursuit eye movements. Nat Commun 2016; 7:12759. [PMID: 27611214 PMCID: PMC5023965 DOI: 10.1038/ncomms12759] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 07/29/2016] [Indexed: 01/16/2023] Open
Abstract
In the natural world, the statistics of sensory stimuli fluctuate across a wide range. In theory, the brain could maximize information recovery if sensory neurons adaptively rescale their sensitivity to the current range of inputs. Such adaptive coding has been observed in a variety of systems, but the premise that adaptation optimizes behaviour has not been tested. Here we show that adaptation in cortical sensory neurons maximizes information about visual motion in pursuit eye movements guided by that cortical activity. We find that gain adaptation drives a rapid (<100 ms) recovery of information after shifts in motion variance, because the neurons and behaviour rescale their sensitivity to motion fluctuations. Both neurons and pursuit rapidly adopt a response gain that maximizes motion information and minimizes tracking errors. Thus, efficient sensory coding is not simply an ideal standard but a description of real sensory computation that manifests in improved behavioural performance.
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Affiliation(s)
- Bing Liu
- Department of Neurobiology, The University of Chicago, 947 East 58th Street, P415 MC0928, Chicago, Illinois 60637, USA
| | - Matthew V. Macellaio
- Department of Neurobiology, The University of Chicago, 947 East 58th Street, P415 MC0928, Chicago, Illinois 60637, USA
| | - Leslie C. Osborne
- Department of Neurobiology, The University of Chicago, 947 East 58th Street, P415 MC0928, Chicago, Illinois 60637, USA
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, Illinois 60637, USA
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17
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Assessment of Methods for the Intracellular Blockade of GABAA Receptors. PLoS One 2016; 11:e0160900. [PMID: 27501143 PMCID: PMC4976935 DOI: 10.1371/journal.pone.0160900] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 07/26/2016] [Indexed: 12/11/2022] Open
Abstract
Selective blockade of inhibitory synaptic transmission onto specific neurons is a useful tool for dissecting the excitatory and inhibitory synaptic components of ongoing network activity. To achieve this, intracellular recording with a patch solution capable of blocking GABAA receptors has advantages over other manipulations, such as pharmacological application of GABAergic antagonists or optogenetic inhibition of populations of interneurones, in that the majority of inhibitory transmission is unaffected and hence the remaining network activity preserved. Here, we assess three previously described methods to block inhibition: intracellular application of the molecules picrotoxin, 4,4’-dinitro-stilbene-2,2’-disulphonic acid (DNDS) and 4,4’-diisothiocyanostilbene-2,2’-disulphonic acid (DIDS). DNDS and picrotoxin were both found to be ineffective at blocking evoked, monosynaptic inhibitory postsynaptic currents (IPSCs) onto mouse CA1 pyramidal cells. An intracellular solution containing DIDS and caesium fluoride, but lacking nucleotides ATP and GTP, was effective at decreasing the amplitude of IPSCs. However, this effect was found to be independent of DIDS, and the absence of intracellular nucleotides, and was instead due to the presence of fluoride ions in this intracellular solution, which also blocked spontaneously occurring IPSCs during hippocampal sharp waves. Critically, intracellular fluoride ions also caused a decrease in both spontaneous and evoked excitatory synaptic currents and precluded the inclusion of nucleotides in the intracellular solution. Therefore, of the methods tested, only fluoride ions were effective for intracellular blockade of IPSCs but this approach has additional cellular effects reducing its selectivity and utility.
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18
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Ferrati G, Martini FJ, Maravall M. Presynaptic Adenosine Receptor-Mediated Regulation of Diverse Thalamocortical Short-Term Plasticity in the Mouse Whisker Pathway. Front Neural Circuits 2016; 10:9. [PMID: 26941610 PMCID: PMC4763074 DOI: 10.3389/fncir.2016.00009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/05/2016] [Indexed: 12/27/2022] Open
Abstract
Short-term synaptic plasticity (STP) sets the sensitivity of a synapse to incoming activity and determines the temporal patterns that it best transmits. In “driver” thalamocortical (TC) synaptic populations, STP is dominated by depression during stimulation from rest. However, during ongoing stimulation, lemniscal TC connections onto layer 4 neurons in mouse barrel cortex express variable STP. Each synapse responds to input trains with a distinct pattern of depression or facilitation around its mean steady-state response. As a result, in common with other synaptic populations, lemniscal TC synapses express diverse rather than uniform dynamics, allowing for a rich representation of temporally varying stimuli. Here, we show that this STP diversity is regulated presynaptically. Presynaptic adenosine receptors of the A1R type, but not kainate receptors (KARs), modulate STP behavior. Blocking the receptors does not eliminate diversity, indicating that diversity is related to heterogeneous expression of multiple mechanisms in the pathway from presynaptic calcium influx to neurotransmitter release.
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Affiliation(s)
- Giovanni Ferrati
- Instituto de Neurociencias de Alicante UMH-CSIC Sant Joan d'Alacant, Spain
| | | | - Miguel Maravall
- Instituto de Neurociencias de Alicante UMH-CSICSant Joan d'Alacant, Spain; School of Life Sciences, Sussex Neuroscience, University of SussexBrighton, UK
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19
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Synaptic diversity enables temporal coding of coincident multisensory inputs in single neurons. Nat Neurosci 2015; 18:718-27. [PMID: 25821914 PMCID: PMC4413433 DOI: 10.1038/nn.3974] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/12/2015] [Indexed: 02/08/2023]
Abstract
The ability of the brain to rapidly process information from multiple pathways is critical for reliable execution of complex sensory-motor behaviors, yet the cellular mechanisms underlying a neuronal representation of multimodal stimuli are poorly understood. Here we explored the possibility that the physiological diversity of mossy fiber (MF) to granule cell (GC) synapses within the mouse vestibulocerebellum may contribute to the processing of coincident multisensory information at the level of individual GCs. We found that the strength and short-term dynamics of individual MF-GC synapses can act as biophysical signatures for primary vestibular, secondary vestibular and visual input pathways. The majority of GCs receive inputs from different modalities, which when co-activated, produced enhanced GC firing rates and distinct first spike latencies. Thus, pathway-specific synaptic response properties permit temporal coding of correlated multisensory input by single GCs, thereby enriching sensory representation and facilitating pattern separation.
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20
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Maravall M, Diamond ME. Algorithms of whisker-mediated touch perception. Curr Opin Neurobiol 2014; 25:176-86. [PMID: 24549178 DOI: 10.1016/j.conb.2014.01.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 01/23/2014] [Indexed: 11/18/2022]
Abstract
Comparison of the functional organization of sensory modalities can reveal the specialized mechanisms unique to each modality as well as processing algorithms that are common across modalities. Here we examine the rodent whisker system. The whisker's mechanical properties shape the forces transmitted to specialized receptors. The sensory and motor systems are intimately interconnected, giving rise to two forms of sensation: generative and receptive. The sensory pathway is a test bed for fundamental concepts in computation and coding: hierarchical feature detection, sparseness, adaptive representations, and population coding. The central processing of signals can be considered a sequence of filters. At the level of cortex, neurons represent object features by a coordinated population code which encompasses cells with heterogeneous properties.
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Affiliation(s)
- Miguel Maravall
- Instituto de Neurociencias de Alicante UMH-CSIC, Campus de San Juan, Apartado 18, 03550 Sant Joan d'Alacant, Spain
| | - Mathew E Diamond
- Tactile Perception and Learning Lab, International School for Advanced Studies-SISSA, Via Bonomea 265, 34136 Trieste, Italy.
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