1
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Sharma H, Azouz R. Global and local neuronal coding of tactile information in the barrel cortex. Front Neurosci 2024; 17:1291864. [PMID: 38249584 PMCID: PMC10796699 DOI: 10.3389/fnins.2023.1291864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 11/24/2023] [Indexed: 01/23/2024] Open
Abstract
During tactile sensation in rodents, the whisker movements across surfaces give rise to intricate whisker motions that encompass discrete and transient stick-slip events, effectively conveying valuable information regarding surface properties. These surface characteristics are transformed into cortical neuronal responses. This study examined the coding strategies underlying these transformations in rat whiskers. We found that changes in surface coarseness modified the number and magnitude of stick-slip events, which in turn both modulated properties of neuronal responses. Global changes in the number of stick-slip events primarily affected neuronal discharge rates and the degree of neuronal synchronization. In contrast, local changes in the magnitude of stick-slip events affected the transformation of these kinematic and kinetic characteristics into neuronal discharges. Most cortical neurons exhibited surface coarseness selectivity through global and local stick-slip event properties. However, this selectivity varied across coding strategies in the same neurons, given that each coding strategy reflected different aspects of changes in whisker-surface interactions. The degree of spatial similarity in surface coarseness preference in adjacently recorded neurons differed among these coding strategies. Adjacently recorded neurons exhibited the same surface coarseness preference in their firing rates but not through other coding strategies. Through these results, we were able to show that local stick-slip event properties contribute to texture discrimination, complementing and surpassing global coding in this context. These findings suggest that the representation of surface coarseness in the cortex may rely on concurrent coding strategies that integrate tactile information across different spatiotemporal scales.
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Affiliation(s)
| | - Rony Azouz
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Be'er Sheva, Southern District, Israel
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2
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Montanari R, Alegre-Cortés J, Alonso-Andrés A, Cabrera-Moreno J, Navarro I, García-Frigola C, Sáez M, Reig R. Callosal inputs generate side-invariant receptive fields in the barrel cortex. SCIENCE ADVANCES 2023; 9:eadi3728. [PMID: 38019920 PMCID: PMC10686559 DOI: 10.1126/sciadv.adi3728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 10/27/2023] [Indexed: 12/01/2023]
Abstract
Barrel cortex integrates contra- and ipsilateral whiskers' inputs. While contralateral inputs depend on the thalamocortical innervation, ipsilateral ones are thought to rely on callosal axons. These are more abundant in the barrel cortex region bordering with S2 and containing the row A-whiskers representation, the row lying nearest to the facial midline. Here, we ask what role this callosal axonal arrangement plays in ipsilateral tactile signaling. We found that novel object exploration with ipsilateral whiskers confines c-Fos expression within the highly callosal subregion. Targeting this area with in vivo patch-clamp recordings revealed neurons with uniquely strong ipsilateral responses dependent on the corpus callosum, as assessed by tetrodotoxin silencing and by optogenetic activation of the contralateral hemisphere. Still, in this area, stimulation of contra- or ipsilateral row A-whiskers evoked an indistinguishable response in some neurons, mostly located in layers 5/6, indicating their involvement in the midline representation of the whiskers' sensory space.
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Affiliation(s)
| | | | | | - Jorge Cabrera-Moreno
- Instituto de Neurociencias UMH-CSIC (Alicante), Avenida Santiago Ramón y Cajal s.n., 03550, Spain
| | | | - Cristina García-Frigola
- Instituto de Neurociencias UMH-CSIC (Alicante), Avenida Santiago Ramón y Cajal s.n., 03550, Spain
| | - María Sáez
- Instituto de Neurociencias UMH-CSIC (Alicante), Avenida Santiago Ramón y Cajal s.n., 03550, Spain
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3
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Lande AS, Garvert AC, Ebbesen NC, Jordbræk SV, Vervaeke K. Representations of tactile object location in the retrosplenial cortex. Curr Biol 2023; 33:4599-4610.e7. [PMID: 37774708 DOI: 10.1016/j.cub.2023.09.019] [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: 11/29/2022] [Revised: 07/23/2023] [Accepted: 09/06/2023] [Indexed: 10/01/2023]
Abstract
How animals use tactile sensation to detect important objects and remember their location in a world-based coordinate system is unclear. Here, we hypothesized that the retrosplenial cortex (RSC), a key network for contextual memory and spatial navigation, represents the location of objects based on tactile sensation. We studied mice palpating objects with their whiskers while navigating in a tactile virtual reality in darkness. Using two-photon Ca2+ imaging, we discovered that a population of neurons in the agranular RSC signal the location of objects. Responses to objects do not simply reflect the sensory stimulus. Instead, they are highly position, task, and context dependent and often predict the upcoming object before it is within reach. In addition, a large fraction of neurons encoding object location maintain a memory trace of the object's location. These data show that the RSC encodes the location and arrangement of tactile objects in a spatial reference frame.
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Affiliation(s)
- Andreas Sigstad Lande
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Sognsvannsveien 9, 0372 Oslo, Norway
| | - Anna Christina Garvert
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Sognsvannsveien 9, 0372 Oslo, Norway
| | - Nora Cecilie Ebbesen
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Sognsvannsveien 9, 0372 Oslo, Norway
| | - Sondre Valentin Jordbræk
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Sognsvannsveien 9, 0372 Oslo, Norway
| | - Koen Vervaeke
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Sognsvannsveien 9, 0372 Oslo, Norway.
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4
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Funamizu A, Marbach F, Zador AM. Stable sound decoding despite modulated sound representation in the auditory cortex. Curr Biol 2023; 33:4470-4483.e7. [PMID: 37802051 PMCID: PMC10665086 DOI: 10.1016/j.cub.2023.09.031] [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: 04/09/2023] [Revised: 07/27/2023] [Accepted: 09/13/2023] [Indexed: 10/08/2023]
Abstract
The activity of neurons in the auditory cortex is driven by both sounds and non-sensory context. To investigate the neuronal correlates of non-sensory context, we trained head-fixed mice to perform a two-alternative-choice auditory task in which either reward or stimulus expectation (prior) was manipulated in blocks. Using two-photon calcium imaging to record populations of single neurons in the auditory cortex, we found that both stimulus and reward expectation modulated the activity of these neurons. A linear decoder trained on this population activity could decode stimuli as well or better than predicted by the animal's performance. Interestingly, the optimal decoder was stable even in the face of variable sensory representations. Neither the context nor the mouse's choice could be reliably decoded from the recorded neural activity. Our findings suggest that, in spite of modulation of auditory cortical activity by task priors, the auditory cortex does not represent sufficient information about these priors to exploit them optimally. Thus, the combination of rapidly changing sensory information with more slowly varying task information required for decisions in this task might be represented in brain regions other than the auditory cortex.
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Affiliation(s)
- Akihiro Funamizu
- Cold Spring Harbor Laboratory, 1 Bungtown Rd, Cold Spring Harbor, NY 11724, USA.
| | - Fred Marbach
- Cold Spring Harbor Laboratory, 1 Bungtown Rd, Cold Spring Harbor, NY 11724, USA
| | - Anthony M Zador
- Cold Spring Harbor Laboratory, 1 Bungtown Rd, Cold Spring Harbor, NY 11724, USA
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5
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Funamizu A, Marbach F, Zador AM. Stable sound decoding despite modulated sound representation in the auditory cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.31.526457. [PMID: 37745428 PMCID: PMC10515783 DOI: 10.1101/2023.01.31.526457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The activity of neurons in the auditory cortex is driven by both sounds and non-sensory context. To investigate the neuronal correlates of non-sensory context, we trained head-fixed mice to perform a two-alternative choice auditory task in which either reward or stimulus expectation (prior) was manipulated in blocks. Using two-photon calcium imaging to record populations of single neurons in auditory cortex, we found that both stimulus and reward expectation modulated the activity of these neurons. A linear decoder trained on this population activity could decode stimuli as well or better than predicted by the animal's performance. Interestingly, the optimal decoder was stable even in the face of variable sensory representations. Neither the context nor the mouse's choice could be reliably decoded from the recorded neural activity. Our findings suggest that in spite of modulation of auditory cortical activity by task priors, auditory cortex does not represent sufficient information about these priors to exploit them optimally and that decisions in this task require that rapidly changing sensory information be combined with more slowly varying task information extracted and represented in brain regions other than auditory cortex.
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Affiliation(s)
- Akihiro Funamizu
- Cold Spring Harbor Laboratory, 1 Bungtown Rd, Cold Spring Harbor, NY 11724, USA
- Present address: Institute for Quantitative Biosciences, the University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 1130032, Japan
- Present address: Department of Life Sciences, Graduate School of Arts and Sciences, the University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 1538902, Japan
| | - Fred Marbach
- Cold Spring Harbor Laboratory, 1 Bungtown Rd, Cold Spring Harbor, NY 11724, USA
- Present address: The Francis Crick Institute, 1 Midland Rd, NW1 4AT London, UK
| | - Anthony M Zador
- Cold Spring Harbor Laboratory, 1 Bungtown Rd, Cold Spring Harbor, NY 11724, USA
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6
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Ahissar E, Nelinger G, Assa E, Karp O, Saraf-Sinik I. Thalamocortical loops as temporal demodulators across senses. Commun Biol 2023; 6:562. [PMID: 37237075 DOI: 10.1038/s42003-023-04881-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
Sensory information is coded in space and in time. The organization of neuronal activity in space maintains straightforward relationships with the spatial organization of the perceived environment. In contrast, the temporal organization of neuronal activity is not trivially related to external features due to sensor motion. Still, the temporal organization shares similar principles across sensory modalities. Likewise, thalamocortical circuits exhibit common features across senses. Focusing on touch, vision, and audition, we review their shared coding principles and suggest that thalamocortical systems include circuits that allow analogous recoding mechanisms in all three senses. These thalamocortical circuits constitute oscillations-based phase-locked loops, that translate temporally-coded sensory information to rate-coded cortical signals, signals that can integrate information across sensory and motor modalities. The loop also allows predictive locking to the onset of future modulations of the sensory signal. The paper thus suggests a theoretical framework in which a common thalamocortical mechanism implements temporal demodulation across senses.
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Affiliation(s)
- Ehud Ahissar
- Department of Brain Sciences, Weizmann Institute, Rehovot, 76100, Israel.
| | - Guy Nelinger
- Department of Brain Sciences, Weizmann Institute, Rehovot, 76100, Israel
| | - Eldad Assa
- Department of Brain Sciences, Weizmann Institute, Rehovot, 76100, Israel
| | - Ofer Karp
- Department of Brain Sciences, Weizmann Institute, Rehovot, 76100, Israel
| | - Inbar Saraf-Sinik
- Department of Brain Sciences, Weizmann Institute, Rehovot, 76100, Israel
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7
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Sharma H, Azouz R. Coexisting neuronal coding strategies in the barrel cortex. Cereb Cortex 2022; 32:4986-5004. [PMID: 35149866 DOI: 10.1093/cercor/bhab527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 12/27/2022] Open
Abstract
During tactile sensation by rodents, whisker movements across surfaces generate complex whisker motions, including discrete, transient stick-slip events, which carry information about surface properties. The characteristics of these events and how the brain encodes this tactile information remain enigmatic. We found that cortical neurons show a mixture of synchronized and nontemporally correlated spikes in their tactile responses. Synchronous spikes convey the magnitude of stick-slip events by numerous aspects of temporal coding. These spikes show preferential selectivity for kinetic and kinematic whisker motion. By contrast, asynchronous spikes in each neuron convey the magnitude of stick-slip events by their discharge rates, response probability, and interspike intervals. We further show that the differentiation between these two types of activity is highly dependent on the magnitude of stick-slip events and stimulus and response history. These results suggest that cortical neurons transmit multiple components of tactile information through numerous coding strategies.
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Affiliation(s)
- Hariom Sharma
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Rony Azouz
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel
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8
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Demonstration of three-dimensional contact point determination and contour reconstruction during active whisking behavior of an awake rat. PLoS Comput Biol 2022; 18:e1007763. [PMID: 36108064 PMCID: PMC9477318 DOI: 10.1371/journal.pcbi.1007763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 05/06/2022] [Indexed: 11/19/2022] Open
Abstract
The rodent vibrissal (whisker) system has been studied for decades as a model of active touch sensing. There are no sensors along the length of a whisker; all sensing occurs at the whisker base. Therefore, a large open question in many neuroscience studies is how an animal could estimate the three-dimensional (3D) location at which a whisker makes contact with an object. In the present work we simulated the shape of a real rat whisker to demonstrate the existence of several unique mappings from triplets of mechanical signals at the whisker base to the three-dimensional whisker-object contact point. We then used high speed video to record whisker deflections as an awake rat whisked against a peg, and used the mechanics resulting from those deflections to extract the contact points along the peg surface. These results demonstrate that measurement of specific mechanical triplets at the base of a biological whisker can enable 3D contact point determination during natural whisking behavior. The approach is viable even though the biological whisker has non-ideal, non-planar curvature, and even given the rat’s real-world choices of whisking parameters. Visual intuition for the quality of the approach is provided in a video that shows the contour of the peg gradually emerging during active whisking behavior.
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9
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Bush NE, Solla SA, Hartmann MJZ. Continuous, multidimensional coding of 3D complex tactile stimuli by primary sensory neurons of the vibrissal system. Proc Natl Acad Sci U S A 2021; 118:e2020194118. [PMID: 34353902 PMCID: PMC8364131 DOI: 10.1073/pnas.2020194118] [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] [Indexed: 11/18/2022] Open
Abstract
Across all sensory modalities, first-stage sensory neurons are an information bottleneck: they must convey all information available for an animal to perceive and act in its environment. Our understanding of coding properties of primary sensory neurons in the auditory and visual systems has been aided by the use of increasingly complex, naturalistic stimulus sets. By comparison, encoding properties of primary somatosensory afferents are poorly understood. Here, we use the rodent whisker system to examine how tactile information is represented in primary sensory neurons of the trigeminal ganglion (Vg). Vg neurons have long been thought to segregate into functional classes associated with separate streams of information processing. However, this view is based on Vg responses to restricted stimulus sets which potentially underreport the coding capabilities of these neurons. In contrast, the current study records Vg responses to complex three-dimensional (3D) stimulation while quantifying the complete 3D whisker shape and mechanics, thereby beginning to reveal their full representational capabilities. The results show that individual Vg neurons simultaneously represent multiple mechanical features of a stimulus, do not preferentially encode principal components of the stimuli, and represent continuous and tiled variations of all available mechanical information. These results directly contrast with proposed codes in which subpopulations of Vg neurons encode select stimulus features. Instead, individual Vg neurons likely overcome the information bottleneck by encoding large regions of a complex sensory space. This proposed tiled and multidimensional representation at the Vg directly constrains the computations performed by more central neurons of the vibrissotrigeminal pathway.
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Affiliation(s)
- Nicholas E Bush
- Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL 60208
| | - Sara A Solla
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208
- Department of Physiology, Northwestern University, Chicago, IL 60611
| | - Mitra J Z Hartmann
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208;
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208
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10
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O'Connor DH, Krubitzer L, Bensmaia S. Of mice and monkeys: Somatosensory processing in two prominent animal models. Prog Neurobiol 2021; 201:102008. [PMID: 33587956 PMCID: PMC8096687 DOI: 10.1016/j.pneurobio.2021.102008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/26/2020] [Accepted: 02/07/2021] [Indexed: 11/20/2022]
Abstract
Our understanding of the neural basis of somatosensation is based largely on studies of the whisker system of mice and rats and the hands of macaque monkeys. Results across these animal models are often interpreted as providing direct insight into human somatosensation. Work on these systems has proceeded in parallel, capitalizing on the strengths of each model, but has rarely been considered as a whole. This lack of integration promotes a piecemeal understanding of somatosensation. Here, we examine the functions and morphologies of whiskers of mice and rats, the hands of macaque monkeys, and the somatosensory neuraxes of these three species. We then discuss how somatosensory information is encoded in their respective nervous systems, highlighting similarities and differences. We reflect on the limitations of these models of human somatosensation and consider key gaps in our understanding of the neural basis of somatosensation.
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Affiliation(s)
- Daniel H O'Connor
- Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, United States; Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, United States
| | - Leah Krubitzer
- Department of Psychology and Center for Neuroscience, University of California at Davis, United States
| | - Sliman Bensmaia
- Department of Organismal Biology and Anatomy, University of Chicago, United States; Committee on Computational Neuroscience, University of Chicago, United States; Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, United States.
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11
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Brown J, Oldenburg IA, Telian GI, Griffin S, Voges M, Jain V, Adesnik H. Spatial integration during active tactile sensation drives orientation perception. Neuron 2021; 109:1707-1720.e7. [PMID: 33826906 PMCID: PMC8944414 DOI: 10.1016/j.neuron.2021.03.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 07/24/2020] [Accepted: 03/11/2021] [Indexed: 01/07/2023]
Abstract
Active haptic sensation is critical for object identification, but its neural circuit basis is poorly understood. We combined optogenetics, two-photon imaging, and high-speed behavioral tracking in mice solving a whisker-based object orientation discrimination task. We found that orientation discrimination required animals to summate input from multiple whiskers specifically along the whisker arc. Animals discriminated the orientation of the stimulus per se as their performance was invariant to the location of the presented stimulus. Populations of barrel cortex neurons summated across whiskers to encode each orientation. Finally, acute optogenetic inactivation of the barrel cortex and cell-type-specific optogenetic suppression of layer 4 excitatory neurons degraded performance, implying that infragranular layers alone are not sufficient to solve the task. These data suggest that spatial summation over an active haptic array generates representations of an object's orientation, which may facilitate encoding of complex three-dimensional objects during active exploration.
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Affiliation(s)
- Jennifer Brown
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Ian Antón Oldenburg
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Gregory I Telian
- The Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Sandon Griffin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Mieke Voges
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Vedant Jain
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Hillel Adesnik
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA; The Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA.
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12
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Gugig E, Sharma H, Azouz R. Gradient of tactile properties in the rat whisker pad. PLoS Biol 2020; 18:e3000699. [PMID: 33090990 PMCID: PMC7608947 DOI: 10.1371/journal.pbio.3000699] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 11/03/2020] [Accepted: 09/14/2020] [Indexed: 11/18/2022] Open
Abstract
The array of vibrissae on a rat's face is the first stage in a high-resolution tactile sensing system. Progressing from rostral to caudal in any vibrissae row results in an increase in whisker length and thickness. This may, in turn, provide a systematic map of separate tactile channels governed by the mechanical properties of the whiskers. To examine whether this map is expressed in a location-dependent transformation of tactile signals into whisker vibrations and neuronal responses, we monitored whiskers' movements across various surfaces and edges. We found a robust rostral-caudal (R-C) gradient of tactile information transmission in which rostral shorter vibrissae displayed a higher sensitivity and bigger differences in response to different textures, whereas longer caudal vibrissae were less sensitive. This gradient is evident in several dynamic properties of vibrissae trajectories. As rodents sample the environment with multiple vibrissae, we found that combining tactile signals from multiple vibrissae resulted in an increased sensitivity and bigger differences in response to the different textures. Nonetheless, we found that texture identity is not represented spatially across the whisker pad. Based on the responses of first-order sensory neurons, we found that they adhere to the tactile information conveyed by the vibrissae. That is, neurons innervating rostral vibrissae were better suited for texture discrimination, whereas neurons innervating caudal vibrissae were more suited for edge detection. These results suggest that the whisker array in rodents forms a sensory structure in which different facets of tactile information are transmitted through location-dependent gradient of vibrissae on the rat's face.
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Affiliation(s)
- Erez Gugig
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hariom Sharma
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Rony Azouz
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- * E-mail:
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13
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Kim J, Erskine A, Cheung JA, Hires SA. Behavioral and Neural Bases of Tactile Shape Discrimination Learning in Head-Fixed Mice. Neuron 2020; 108:953-967.e8. [PMID: 33002411 DOI: 10.1016/j.neuron.2020.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 07/31/2020] [Accepted: 09/08/2020] [Indexed: 11/29/2022]
Abstract
Tactile shape recognition requires the perception of object surface angles. We investigate how neural representations of object angles are constructed from sensory input and how they reorganize across learning. Head-fixed mice learned to discriminate object angles by active exploration with one whisker. Calcium imaging of layers 2-4 of the barrel cortex revealed maps of object-angle tuning before and after learning. Three-dimensional whisker tracking demonstrated that the sensory input components that best discriminate angles (vertical bending and slide distance) also have the greatest influence on object-angle tuning. Despite the high turnover in active ensemble membership across learning, the population distribution of object-angle tuning preferences remained stable. Angle tuning sharpened, but only in neurons that preferred trained angles. This was correlated with a selective increase in the influence of the most task-relevant sensory component on object-angle tuning. These results show how discrimination training enhances stimulus selectivity in the primary somatosensory cortex while maintaining perceptual stability.
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Affiliation(s)
- Jinho Kim
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Andrew Erskine
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Jonathan Andrew Cheung
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Samuel Andrew Hires
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA.
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14
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Deutsch D, Schneidman E, Ahissar E. Generalization of Object Localization From Whiskers to Other Body Parts in Freely Moving Rats. Front Integr Neurosci 2019; 13:64. [PMID: 31736724 PMCID: PMC6839537 DOI: 10.3389/fnint.2019.00064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 10/16/2019] [Indexed: 11/13/2022] Open
Abstract
Rats can be trained to associate relative spatial locations of objects with the spatial location of rewards. Here we ask whether rats can localize static silent objects with other body parts in the dark, and if so with what resolution. We addressed these questions in trained rats, whose interactions with the objects were tracked at high-resolution before and after whisker trimming. We found that rats can use other body parts, such as trunk and ears, to localize objects. Localization resolution with non-whisking body parts (henceforth, ‘body’) was poorer than that obtained with whiskers, even when left with a single whisker at each side. Part of the superiority of whiskers was obtained via the use of multiple contacts. Transfer from whisker to body localization occurred within one session, provided that body contacts with the objects occurred before whisker trimming, or in the next session otherwise. This transfer occurred whether temporal cues were used for discrimination or when discrimination was based on spatial cues alone. Rats’ decision in each trial was based on the sensory cues acquired in that trial and on decisions and reward locations in previous trials. When sensory cues were acquired by body contacts, rat decisions relied more on the reward location in previous trials. Overall, the results suggest that rats can generalize the idea of relative object location across different body parts, while preferring to rely on whiskers-based localization, which occurs earlier and conveys higher resolution.
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Affiliation(s)
- David Deutsch
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
| | - Elad Schneidman
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
| | - Ehud Ahissar
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
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15
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Adibi M. Whisker-Mediated Touch System in Rodents: From Neuron to Behavior. Front Syst Neurosci 2019; 13:40. [PMID: 31496942 PMCID: PMC6712080 DOI: 10.3389/fnsys.2019.00040] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 08/02/2019] [Indexed: 01/02/2023] Open
Abstract
A key question in systems neuroscience is to identify how sensory stimuli are represented in neuronal activity, and how the activity of sensory neurons in turn is “read out” by downstream neurons and give rise to behavior. The choice of a proper model system to address these questions, is therefore a crucial step. Over the past decade, the increasingly powerful array of experimental approaches that has become available in non-primate models (e.g., optogenetics and two-photon imaging) has spurred a renewed interest for the use of rodent models in systems neuroscience research. Here, I introduce the rodent whisker-mediated touch system as a structurally well-established and well-organized model system which, despite its simplicity, gives rise to complex behaviors. This system serves as a behaviorally efficient model system; known as nocturnal animals, along with their olfaction, rodents rely on their whisker-mediated touch system to collect information about their surrounding environment. Moreover, this system represents a well-studied circuitry with a somatotopic organization. At every stage of processing, one can identify anatomical and functional topographic maps of whiskers; “barrelettes” in the brainstem nuclei, “barreloids” in the sensory thalamus, and “barrels” in the cortex. This article provides a brief review on the basic anatomy and function of the whisker system in rodents.
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Affiliation(s)
- Mehdi Adibi
- School of Psychology, University of New South Wales, Sydney, NSW, Australia.,Tactile Perception and Learning Lab, International School for Advanced Studies (SISSA), Trieste, Italy.,Padua Neuroscience Center, University of Padua, Padua, Italy
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16
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Severson KS, Xu D, Yang H, O'Connor DH. Coding of whisker motion across the mouse face. eLife 2019; 8:41535. [PMID: 30816844 PMCID: PMC6395061 DOI: 10.7554/elife.41535] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 02/11/2019] [Indexed: 12/15/2022] Open
Abstract
Haptic perception synthesizes touch with proprioception, the sense of body position. Humans and mice alike experience rich active touch of the face. Because most facial muscles lack proprioceptor endings, the sensory basis of facial proprioception remains unsolved. Facial proprioception may instead rely on mechanoreceptors that encode both touch and self-motion. In rodents, whisker mechanoreceptors provide a signal that informs the brain about whisker position. Whisking involves coordinated orofacial movements, so mechanoreceptors innervating facial regions other than whiskers could also provide information about whisking. To define all sources of sensory information about whisking available to the brain, we recorded spikes from mechanoreceptors innervating diverse parts of the face. Whisker motion was encoded best by whisker mechanoreceptors, but also by those innervating whisker pad hairy skin and supraorbital vibrissae. Redundant self-motion responses may provide the brain with a stable proprioceptive signal despite mechanical perturbations during active touch.
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Affiliation(s)
- Kyle S Severson
- The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Brain Science Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Duo Xu
- The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Brain Science Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Hongdian Yang
- The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Brain Science Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Daniel H O'Connor
- The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Brain Science Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
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17
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Xu X, Xiao S, Yi Z, Peng X, Liu Y. Orthogonal Principal Coefficients Embedding for Unsupervised Subspace Learning. IEEE Trans Cogn Dev Syst 2018. [DOI: 10.1109/tcds.2017.2686983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Abstract
A fundamental question in the investigation of any sensory system is what physical signals drive its sensory neurons during natural behavior. Surprisingly, in the whisker system, it is only recently that answers to this question have emerged. Here, we review the key developments, focussing mainly on the first stage of the ascending pathway - the primary whisker afferents (PWAs). We first consider a biomechanical framework, which describes the fundamental mechanical forces acting on the whiskers during active sensation. We then discuss technical progress that has allowed such mechanical variables to be estimated in awake, behaving animals. We discuss past electrophysiological evidence concerning how PWAs function and reinterpret it within the biomechanical framework. Finally, we consider recent studies of PWAs in awake, behaving animals and compare the results to related studies of the cortex. We argue that understanding 'what the whiskers tell the brain' sheds valuable light on the computational functions of downstream neural circuits, in particular, the barrel cortex.
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19
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Haridas S, Ganapathi R, Kumar M, Manda K. Whisker dependent responsiveness of C57BL/6J mice to different behavioral test paradigms. Behav Brain Res 2017; 336:51-58. [PMID: 28822693 DOI: 10.1016/j.bbr.2017.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/24/2017] [Accepted: 08/05/2017] [Indexed: 11/28/2022]
Abstract
Whisker trimming is very common in C57BL/6J mice. Dewhiskering may lead to an alteration in the thalamocortical connectivity and relevant behavioral functions. Since C57BL/6J is a commonly used strain for neurobehavioral studies, it is important to examine how whisker dependent heterogeneity affects the internal validity of behavioral phenotypes. The present study aimed to investigate the responsiveness of mice to different behavioral test paradigms in the presence or absence of whiskers. We employed two models of whisker deprivation: Acute Whisker Desensitization (AWD) and Chronic Habitual Dewhiskering (CHD). The AWD model blocks whisker sensation by lidocaine application. For CHD model, mice at the age of 12 weeks were carefully scrutinized for presence or absence of whiskers and divided into three groups, the whiskered mice, partially dewhiskered mice and completely dewhiskered mice. The whisker-dependent behavioral functions were assessed using open field test, novel object recognition test, marble burying test and forced swim test. Our results showed that habitual dewhiskering significantly altered the short-term memory and basal anxiety-like functions. Such behavioral alteration due to dewhiskering was significantly different in fully and partially dewhiskered mice, which is indicative of behavioral adaptation to the whisker desensitization. Contrary to CHD, the Acute Whisker Desensitization ameliorated behavioral compulsivity and basal anxiety. Our results suggest that vibrissal desensitization in the mice may lead to changes in their affective and cognitive state. Since, heterogeneity in whisker status may affect behavioral functions, careful inspection of the whisker status of C57BL/6J mice is recommended to increase the reproducibility and reliability of results obtained from behavioral assessments.
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Affiliation(s)
- Seenu Haridas
- NeuroBehavior Laboratory, Institute of Nuclear Medicine and Allied Sciences, Delhi, 110054, India
| | - Ramya Ganapathi
- NeuroBehavior Laboratory, Institute of Nuclear Medicine and Allied Sciences, Delhi, 110054, India
| | - Mayank Kumar
- NeuroBehavior Laboratory, Institute of Nuclear Medicine and Allied Sciences, Delhi, 110054, India
| | - Kailash Manda
- NeuroBehavior Laboratory, Institute of Nuclear Medicine and Allied Sciences, Delhi, 110054, India.
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20
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Kwon SE, Tsytsarev V, Erzurumlu RS, O'Connor DH. Organization of orientation-specific whisker deflection responses in layer 2/3 of mouse somatosensory cortex. Neuroscience 2017; 368:46-56. [PMID: 28827090 DOI: 10.1016/j.neuroscience.2017.07.067] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 11/18/2022]
Abstract
The rodent whisker-barrel system is characterized by its patterned somatotopic mapping between the sensory periphery and multiple regions of the brain. While somatotopy in the whisker system is established, we know far less about how preferences for stimulus orientation or other features are organized. Mouse somatosensation is an increasingly popular model for circuit-based dissection of perceptual decision making and learning, yet our understanding of how stimulus feature representations are organized in the cortex is incomplete. Here, we used in vivo two-photon calcium imaging to monitor activity of populations of layer (L) 2/3 neurons in the mouse primary somatosensory cortex during deflections of a single whisker in two orthogonal orientations (azimuthal or elevational). We split the population response to whisker deflections into an orientation-specific component and a non-specific component that reflected overall excitability in response to deflection of a single whisker. Orientation-specific responses were organized in a locally heterogeneous and spatially distributed manner. Correlations in the stimulus-independent trial-to-trial variability of pairs of neurons were higher among neurons that preferred the same orientation. These correlations depended on similarity in both orientation-specific and non-specific components of responses to single-whisker deflections. Our results shed light on L2/3 organization in mouse somatosensory cortex, and lay a foundation for dissecting circuit mechanisms of perceptual learning and decision-making during orientation discrimination tasks.
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Affiliation(s)
- Sung Eun Kwon
- The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Brain Science Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Reha S Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Daniel H O'Connor
- The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Brain Science Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, United States.
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21
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Whisking mechanics and active sensing. Curr Opin Neurobiol 2016; 40:178-188. [PMID: 27632212 DOI: 10.1016/j.conb.2016.08.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 08/03/2016] [Accepted: 08/04/2016] [Indexed: 11/20/2022]
Abstract
We describe recent advances in quantifying the three-dimensional (3D) geometry and mechanics of whisking. Careful delineation of relevant 3D reference frames reveals important geometric and mechanical distinctions between the localization problem ('where' is an object) and the feature extraction problem ('what' is an object). Head-centered and resting-whisker reference frames lend themselves to quantifying temporal and kinematic cues used for object localization. The whisking-centered reference frame lends itself to quantifying the contact mechanics likely associated with feature extraction. We offer the 'windowed sampling' hypothesis for active sensing: that rats can estimate an object's spatial features by integrating mechanical information across whiskers during brief (25-60ms) windows of 'haptic enclosure' with the whiskers, a motion that resembles a hand grasp.
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22
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Yang AET, Hartmann MJZ. Whisking Kinematics Enables Object Localization in Head-Centered Coordinates Based on Tactile Information from a Single Vibrissa. Front Behav Neurosci 2016; 10:145. [PMID: 27486390 PMCID: PMC4949211 DOI: 10.3389/fnbeh.2016.00145] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 06/23/2016] [Indexed: 11/13/2022] Open
Abstract
During active tactile exploration with their whiskers (vibrissae), rodents can rapidly orient to an object even though there are very few proprioceptors in the whisker muscles. Thus a long-standing question in the study of the vibrissal system is how the rat can localize an object in head-centered coordinates without muscle-based proprioception. We used a three-dimensional model of whisker bending to simulate whisking motions against a peg to investigate the possibility that the 3D mechanics of contact from a single whisker are sufficient for localization in head-centered coordinates. Results show that for nearly all whiskers in the array, purely tactile signals at the whisker base - as would be measured by mechanoreceptors, in whisker-centered coordinates - could be used to determine the location of a vertical peg in head-centered coordinates. Both the "roll" and the "elevation" components of whisking kinematics contribute to the uniqueness and resolution of the localization. These results offer an explanation for a behavioral study showing that rats can more accurately determine the horizontal angle of an object if one column, rather than one row, of whiskers is spared.
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Affiliation(s)
- Anne E T Yang
- Department of Mechanical Engineering, Northwestern University, Evanston IL, USA
| | - Mitra J Z Hartmann
- Department of Mechanical Engineering, Northwestern University, EvanstonIL, USA; Department of Biomedical Engineering, Northwestern University, EvanstonIL, USA
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23
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Sabri MM, Adibi M, Arabzadeh E. Dynamics of Population Activity in Rat Sensory Cortex: Network Correlations Predict Anatomical Arrangement and Information Content. Front Neural Circuits 2016; 10:49. [PMID: 27458347 PMCID: PMC4933716 DOI: 10.3389/fncir.2016.00049] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/22/2016] [Indexed: 12/14/2022] Open
Abstract
To study the spatiotemporal dynamics of neural activity in a cortical population, we implanted a 10 × 10 microelectrode array in the vibrissal cortex of urethane-anesthetized rats. We recorded spontaneous neuronal activity as well as activity evoked in response to sustained and brief sensory stimulation. To quantify the temporal dynamics of activity, we computed the probability distribution function (PDF) of spiking on one electrode given the observation of a spike on another. The spike-triggered PDFs quantified the strength, temporal delay, and temporal precision of correlated activity across electrodes. Nearby cells showed higher levels of correlation at short delays, whereas distant cells showed lower levels of correlation, which tended to occur at longer delays. We found that functional space built based on the strength of pairwise correlations predicted the anatomical arrangement of electrodes. Moreover, the correlation profile of electrode pairs during spontaneous activity predicted the "signal" and "noise" correlations during sensory stimulation. Finally, mutual information analyses revealed that neurons with stronger correlations to the network during spontaneous activity, conveyed higher information about the sensory stimuli in their evoked response. Given the 400-μm-distance between adjacent electrodes, our functional quantifications unravel the spatiotemporal dynamics of activity among nearby and distant cortical columns.
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Affiliation(s)
- Mohammad Mahdi Sabri
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM)Tehran, Iran; Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National UniversityCanberra, ACT, Australia; Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University NodeCanberra, ACT, Australia
| | - Mehdi Adibi
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National UniversityCanberra, ACT, Australia; Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University NodeCanberra, ACT, Australia; School of Psychology, University of New South WalesSydney, NSW, Australia
| | - Ehsan Arabzadeh
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National UniversityCanberra, ACT, Australia; Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University NodeCanberra, ACT, Australia
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24
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Bush NE, Schroeder CL, Hobbs JA, Yang AE, Huet LA, Solla SA, Hartmann MJ. Decoupling kinematics and mechanics reveals coding properties of trigeminal ganglion neurons in the rat vibrissal system. eLife 2016; 5. [PMID: 27348221 PMCID: PMC4999311 DOI: 10.7554/elife.13969] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 06/26/2016] [Indexed: 11/13/2022] Open
Abstract
Tactile information available to the rat vibrissal system begins as external forces that cause whisker deformations, which in turn excite mechanoreceptors in the follicle. Despite the fundamental mechanical origin of tactile information, primary sensory neurons in the trigeminal ganglion (Vg) have often been described as encoding the kinematics (geometry) of object contact. Here we aimed to determine the extent to which Vg neurons encode the kinematics vs. mechanics of contact. We used models of whisker bending to quantify mechanical signals (forces and moments) at the whisker base while simultaneously monitoring whisker kinematics and recording single Vg units in both anesthetized rats and awake, body restrained rats. We employed a novel manual stimulation technique to deflect whiskers in a way that decouples kinematics from mechanics, and used Generalized Linear Models (GLMs) to show that Vg neurons more directly encode mechanical signals when the whisker is deflected in this decoupled stimulus space. DOI:http://dx.doi.org/10.7554/eLife.13969.001 Animals must gather sensory information from the world around them and act on that information. Specialized sensory cells convert physical information from the environment into electrical signals that the brain can interpret. In the case of hearing, this physical information consists of changes in air pressure, and for vision, it is patterns of light bouncing off of objects. Rodents rely heavily on touch information from their whiskers to explore their world. When a whisker touches an object, it deforms and bends. The first neurons to respond to whisker touch – so called primary sensory neurons – represent contact between the whisker and the object in the form of electrical signals, but exactly how they do this is unclear. One possibility is that primary sensory neurons encode the movement of the whisker itself. Whenever a whisker touches an object, the whisker is deflected in a particular direction by a particular amount and at a particular speed. These movement-related features are referred to as the “kinematic” properties of whisker-object contact. Alternatively, these whisker sensory neurons might be more concerned with the forces at the base of the whisker caused by object contact. These forces are the “mechanical” properties of whisker-object contact. Bush, Schroeder et al. set out to determine whether the electrical response of these whisker sensory neurons mainly encode kinematic or mechanical information. However, these two types of information are often closely related to each other: put simply, small whisker movements tend to accompany small forces and vice versa. Bush, Schroeder et al. therefore devised a method to deliver touch stimuli to the whiskers in a way that separates kinematic from mechanical information. Mathematical models were then developed to compare how well the neurons represent each type of information. The models showed that whisker sensory neurons generally encode mechanical signals more directly than kinematic ones. This information adds to our understanding of how animals learn about the world through their senses. However, the analysis of Bush, Schroeder et al. relies on the long-standing simplification that whisker motion is two-dimensional, whereas in reality whiskers move in three dimensions. Therefore, a future challenge is to examine how sensory neurons represent information about touch, such as the location or shape of an object, during three-dimensional whisker-object contact. DOI:http://dx.doi.org/10.7554/eLife.13969.002
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Affiliation(s)
- Nicholas E Bush
- Interdepartmental Neuroscience Program, Northwestern University, Evanston, United States
| | | | - Jennifer A Hobbs
- Department of Physics and Astronomy, Northwestern University, Evanston, United States
| | - Anne Et Yang
- Department of Mechanical Engineering, Northwestern University, Evanston, United States
| | - Lucie A Huet
- Department of Mechanical Engineering, Northwestern University, Evanston, United States
| | - Sara A Solla
- Department of Physics and Astronomy, Northwestern University, Evanston, United States.,Department of Physiology, Northwestern University, Chicago, United States
| | - Mitra Jz Hartmann
- Department of Biomedical Engineering, Northwestern University, Evanston, United States.,Department of Mechanical Engineering, Northwestern University, Evanston, United States
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25
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Abstract
Perception of external objects involves sensory acquisition via the relevant sensory organs. A widely-accepted assumption is that the sensory organ is the first station in a serial chain of processing circuits leading to an internal circuit in which a percept emerges. This open-loop scheme, in which the interaction between the sensory organ and the environment is not affected by its concurrent downstream neuronal processing, is strongly challenged by behavioral and anatomical data. We present here a hypothesis in which the perception of external objects is a closed-loop dynamical process encompassing loops that integrate the organism and its environment and converging towards organism-environment steady-states. We discuss the consistency of closed-loop perception (CLP) with empirical data and show that it can be synthesized in a robotic setup. Testable predictions are proposed for empirical distinction between open and closed loop schemes of perception.
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Affiliation(s)
- Ehud Ahissar
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Eldad Assa
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
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26
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Fazlali Z, Ranjbar-Slamloo Y, Adibi M, Arabzadeh E. Correlation between Cortical State and Locus Coeruleus Activity: Implications for Sensory Coding in Rat Barrel Cortex. Front Neural Circuits 2016; 10:14. [PMID: 27047339 PMCID: PMC4805600 DOI: 10.3389/fncir.2016.00014] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 03/04/2016] [Indexed: 11/17/2022] Open
Abstract
Cortical state modulates the background activity of cortical neurons, and their evoked response to sensory stimulation. Multiple mechanisms are involved in switching between cortical states including various neuromodulatory systems. Locus Coeruleus (LC) is one of the major neuromodulatory nuclei in the brainstem with widespread projections throughout the brain and modulates the activity of cells and networks. Here, we quantified the link between the LC spontaneous activity, cortical state and sensory processing in the rat vibrissal somatosensory "barrel" cortex (BC). We simultaneously recorded unit activity from LC and BC along with prefrontal electroencephalogram (EEG) while presenting brief whisker deflections under urethane anesthesia. The ratio of low to high frequency components of EEG (referred to as the L/H ratio) was employed to identify cortical state. We found that the spontaneous activity of LC units exhibited a negative correlation with the L/H ratio. Cross-correlation analysis revealed that changes in LC firing preceded changes in the cortical state: the correlation of the LC firing profile with the L/H ratio was maximal at an average lag of -1.2 s. We further quantified BC neuronal responses to whisker stimulation during the synchronized and desynchronized states. In the desynchronized state, BC neurons showed lower stimulus detection threshold, higher response fidelity, and shorter response latency. The most prominent change was observed in the late phase of BC evoked activity (100-400 ms post stimulus onset): almost every BC unit exhibited a greater late response during the desynchronized state. Categorization of the BC evoked responses based on LC activity (into high and low LC discharge rates) resulted in highly similar response profiles compared to categorization based on the cortical state (low and high L/H ratios). These findings provide evidence for the involvement of the LC neuromodulatory system in desynchronization of cortical state and the consequent enhancement of sensory coding efficiency.
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Affiliation(s)
- Zeinab Fazlali
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM)Tehran, Iran
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National UniversityCanberra, ACT, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University NodeCanberra, ACT, Australia
| | - Yadollah Ranjbar-Slamloo
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM)Tehran, Iran
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National UniversityCanberra, ACT, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University NodeCanberra, ACT, Australia
| | - Mehdi Adibi
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National UniversityCanberra, ACT, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University NodeCanberra, ACT, Australia
| | - Ehsan Arabzadeh
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National UniversityCanberra, ACT, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University NodeCanberra, ACT, Australia
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27
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Hobbs JA, Towal RB, Hartmann MJZ. Evidence for Functional Groupings of Vibrissae across the Rodent Mystacial Pad. PLoS Comput Biol 2016; 12:e1004109. [PMID: 26745501 PMCID: PMC4706419 DOI: 10.1371/journal.pcbi.1004109] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 01/05/2015] [Indexed: 12/02/2022] Open
Abstract
During natural exploration, rats exhibit two particularly conspicuous vibrissal-mediated behaviors: they follow along walls, and “dab” their snouts on the ground at frequencies related to the whisking cycle. In general, the walls and ground may be located at any distance from, and at any orientation relative to, the rat’s head, which raises the question of how the rat might determine the position and orientation of these surfaces. Previous studies have compellingly demonstrated that rats can accurately determine the horizontal angle at which a vibrissa first touches an object, and we therefore asked whether this parameter could provide the rat with information about the pitch, distance, and yaw of a surface relative to its head. We used a three-dimensional model of the whisker array to construct mappings between the horizontal angle of contact of each vibrissa and every possible (pitch, distance, and yaw) configuration of the head relative to a flat surface. The mappings revealed striking differences in the patterns of contact for vibrissae in different regions of the array. The exterior (A, D, E) rows provide information about the relative pitch of the surface regardless of distance. The interior (B, C) rows provide distance cues regardless of head pitch. Yaw is linearly correlated with the difference between the number of right and left whiskers touching the surface. Compared to the long reaches that whiskers can make to the side and below the rat, the reachable distance in front of the rat’s nose is relatively small. We confirmed key predictions of these functional groupings in a behavioral experiment that monitored the contact patterns that the vibrissae made with a flat vertical surface. These results suggest that vibrissae in different regions of the array are not interchangeable sensors, but rather functionally grouped to acquire particular types of information about the environment. Animals do not passively sense the world. They actively move their sensors to acquire the information best suited to their current behavioral needs. Thus, to study neural processing in any sensory system, it is critical to determine the spatiotemporal structure of the inputs to that system. The rat whisker system is a well-studied model of active sensing because rats rhythmically brush and tap their vibrissae against objects during tactual exploration. To date, however, the patterns of sensory input during vibrisso-tactile exploration have not been quantified. This study quantifies some of the statistics of vibrissal-surface contact, focusing specifically on the angle of contact with a flat surface. Given that during exploration the rat could encounter a surface at any position and orientation relative to its head, we simulated the spatial patterns of vibrissal contact for all possible head-surface configurations. Results reveal functional groupings of whiskers across the array, with different whiskers being better suited for different aspects of tactile sensory tasks than others. Key predictions of the simulations were validated in a behavioral experiment that monitored vibrissal contact patterns with a flat wall. These results provide some of the first quantitative insights into the “natural tactile scene” for the vibrisso-trigeminal system.
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Affiliation(s)
- Jennifer A. Hobbs
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois, United States of America
| | - R. Blythe Towal
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States of America
| | - Mitra J. Z. Hartmann
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States of America
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, United States of America
- * E-mail:
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28
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Hobbs JA, Towal RB, Hartmann MJZ. Spatiotemporal Patterns of Contact Across the Rat Vibrissal Array During Exploratory Behavior. Front Behav Neurosci 2016; 9:356. [PMID: 26778990 PMCID: PMC4700281 DOI: 10.3389/fnbeh.2015.00356] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 12/08/2015] [Indexed: 11/13/2022] Open
Abstract
The rat vibrissal system is an important model for the study of somatosensation, but the small size and rapid speed of the vibrissae have precluded measuring precise vibrissal-object contact sequences during behavior. We used a laser light sheet to quantify, with 1 ms resolution, the spatiotemporal structure of whisker-surface contact as five naïve rats freely explored a flat, vertical glass wall. Consistent with previous work, we show that the whisk cycle cannot be uniquely defined because different whiskers often move asynchronously, but that quasi-periodic (~8 Hz) variations in head velocity represent a distinct temporal feature on which to lock analysis. Around times of minimum head velocity, whiskers protract to make contact with the surface, and then sustain contact with the surface for extended durations (~25-60 ms) before detaching. This behavior results in discrete temporal windows in which large numbers of whiskers are in contact with the surface. These "sustained collective contact intervals" (SCCIs) were observed on 100% of whisks for all five rats. The overall spatiotemporal structure of the SCCIs can be qualitatively predicted based on information about head pose and the average whisk cycle. In contrast, precise sequences of whisker-surface contact depend on detailed head and whisker kinematics. Sequences of vibrissal contact were highly variable, equally likely to propagate in all directions across the array. Somewhat more structure was found when sequences of contacts were examined on a row-wise basis. In striking contrast to the high variability associated with contact sequences, a consistent feature of each SCCI was that the contact locations of the whiskers on the glass converged and moved more slowly on the sheet. Together, these findings lead us to propose that the rat uses a strategy of "windowed sampling" to extract an object's spatial features: specifically, the rat spatially integrates quasi-static mechanical signals across whiskers during the period of sustained contact, resembling an "enclosing" haptic procedure.
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Affiliation(s)
- Jennifer A Hobbs
- Department of Physics and Astronomy, Northwestern University Evanston, IL, USA
| | - R Blythe Towal
- Department of Biomedical Engineering, Northwestern University Evanston, IL, USA
| | - Mitra J Z Hartmann
- Department of Biomedical Engineering, Northwestern UniversityEvanston, IL, USA; Department of Mechanical Engineering, Northwestern UniversityEvanston, IL, USA
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Sofroniew NJ, Vlasov YA, Hires SA, Freeman J, Svoboda K. Neural coding in barrel cortex during whisker-guided locomotion. eLife 2015; 4. [PMID: 26701910 PMCID: PMC4764557 DOI: 10.7554/elife.12559] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 12/21/2015] [Indexed: 11/15/2022] Open
Abstract
Animals seek out relevant information by moving through a dynamic world, but sensory systems are usually studied under highly constrained and passive conditions that may not probe important dimensions of the neural code. Here, we explored neural coding in the barrel cortex of head-fixed mice that tracked walls with their whiskers in tactile virtual reality. Optogenetic manipulations revealed that barrel cortex plays a role in wall-tracking. Closed-loop optogenetic control of layer 4 neurons can substitute for whisker-object contact to guide behavior resembling wall tracking. We measured neural activity using two-photon calcium imaging and extracellular recordings. Neurons were tuned to the distance between the animal snout and the contralateral wall, with monotonic, unimodal, and multimodal tuning curves. This rich representation of object location in the barrel cortex could not be predicted based on simple stimulus-response relationships involving individual whiskers and likely emerges within cortical circuits. DOI:http://dx.doi.org/10.7554/eLife.12559.001 Mice are primarily nocturnal animals that rely on their whiskers to navigate dark underground burrows and winding corridors. When a whisker touches an object, cells called neurons at the base of the whiskers produce electrical signals that are relayed to other neurons in an area of the brain called the barrel cortex. However, it is not clear how information is encoded in these electrical signals, in part, because it is technically challenging to collect data about neuron activity and behavior while the mice move around. To overcome these difficulties, Sofroniew, Vlasov et al. used a touch-based (or 'tactile') virtual reality system to study how mice navigate along corridors. The system simulated the contact the whiskers would have with the walls of a winding corridor. This was achieved by moving the walls with motors while holding the mouse still enough to be able to measure the activity of neurons in the barrel cortex and observe the behavior of the animal. The experiments show that the electrical signals in the barrel cortex encode information about motion as well as the distance between the mouse and the wall. For example, some neurons in the barrel cortex were only activated when a mouse was a particular distance from the walls. The experiments suggest that the barrel cortex processes signals received from several whiskers to build an overall picture of the locations and shapes of objects. Sofroniew, Vlasov et al. also used a technique called optogenetics to deliberately activate particular neurons in a manner that mimics their activity patterns during interactions with walls. In the absence of walls, the optogenetic stimuli guided the behavior of the mice so that they tracked along the paths of 'illusory' corridors. Together, these findings reveal the neural code in the barrel cortex that allows mice to navigate by touch. DOI:http://dx.doi.org/10.7554/eLife.12559.002
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Affiliation(s)
| | - Yurii A Vlasov
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,IBM Thomas J. Watson Research Center, New York, United States
| | - Samuel Andrew Hires
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Jeremy Freeman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Karel Svoboda
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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30
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Motion makes sense: an adaptive motor-sensory strategy underlies the perception of object location in rats. J Neurosci 2015; 35:8777-89. [PMID: 26063912 DOI: 10.1523/jneurosci.4149-14.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Tactile perception is obtained by coordinated motor-sensory processes. We studied the processes underlying the perception of object location in freely moving rats. We trained rats to identify the relative location of two vertical poles placed in front of them and measured at high resolution the motor and sensory variables (19 and 2 variables, respectively) associated with this whiskers-based perceptual process. We found that the rats developed stereotypic head and whisker movements to solve this task, in a manner that can be described by several distinct behavioral phases. During two of these phases, the rats' whiskers coded object position by first temporal and then angular coding schemes. We then introduced wind (in two opposite directions) and remeasured their perceptual performance and motor-sensory variables. Our rats continued to perceive object location in a consistent manner under wind perturbations while maintaining all behavioral phases and relatively constant sensory coding. Constant sensory coding was achieved by keeping one group of motor variables (the "controlled variables") constant, despite the perturbing wind, at the cost of strongly modulating another group of motor variables (the "modulated variables"). The controlled variables included coding-relevant variables, such as head azimuth and whisker velocity. These results indicate that consistent perception of location in the rat is obtained actively, via a selective control of perception-relevant motor variables.
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31
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Haidarliu S, Kleinfeld D, Deschênes M, Ahissar E. The Musculature That Drives Active Touch by Vibrissae and Nose in Mice. Anat Rec (Hoboken) 2014; 298:1347-58. [PMID: 25408106 DOI: 10.1002/ar.23102] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 10/21/2014] [Accepted: 10/26/2014] [Indexed: 11/06/2022]
Abstract
Coordinated action of facial muscles during whisking, sniffing, and touching objects is an important component of active sensing in rodents. Accumulating evidence suggests that the anatomical schemes that underlie active sensing are similar across the majority of whisking rodents. Intriguingly, however, muscle architecture in the mystacial pad of the mouse was reported to be different, possessing only one extrinsic vibrissa protracting muscle (M. nasalis) in the rostral part of the snout. In this study, the organization of the muscles that move the nose and the mystacial vibrissae in mice was re-examined and compared with that reported previously in other rodents. We found that muscle distribution within the mystacial pad and around the tip of the nose in mice is isomorphic with that found in other whisking rodents. In particular, in the rostral part of the mouse snout, we describe both protractors and retractors of the vibrissae. Nose movements are controlled by the M. dilator nasi and five subunits of the M. nasolabialis profundus, with involvement of the nasal cartilaginous skeleton as a mediator in the muscular effort translation.
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Affiliation(s)
- Sebastian Haidarliu
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
| | - David Kleinfeld
- Department of Physics and Section of Neurobiology, University of California at San Diego, La Jolla, California
| | - Martin Deschênes
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Laval University, Québec City, Canada
| | - Ehud Ahissar
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
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32
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Abstract
When encountering novel environments, animals perform complex yet structured exploratory behaviors. Despite their typical structuring, the principles underlying exploratory patterns are still not sufficiently understood. Here we analyzed exploratory behavioral data from two modalities: whisking and locomotion in rats and mice. We found that these rodents maximized novelty signal-to-noise ratio during each exploration episode, where novelty is defined as the accumulated information gain. We further found that these rodents maximized novelty during outbound exploration, used novelty-triggered withdrawal-like retreat behavior, and explored the environment in a novelty-descending sequence. We applied a hierarchical curiosity model, which incorporates these principles, to both modalities. We show that the model captures the major components of exploratory behavior in multiple timescales: single excursions, exploratory episodes, and developmental timeline. The model predicted that novelty is managed across exploratory modalities. Using a novel experimental setup in which mice encountered a novel object for the first time in their life, we tested and validated this prediction. Further predictions, related to the development of brain circuitry, are described. This study demonstrates that rodents select exploratory actions according to a novelty management framework and suggests a plausible mechanism by which mammalian exploration primitives can be learned during development and integrated in adult exploration of complex environments.
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33
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Voigts J, Herman DH, Celikel T. Tactile object localization by anticipatory whisker motion. J Neurophysiol 2014; 113:620-32. [PMID: 25339711 DOI: 10.1152/jn.00241.2014] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Rodents use rhythmic protractions of their whiskers to locate objects in space. The amplitude of these protractions is reduced when whiskers contact objects, leading to a tendency of whiskers to only lightly touch the environment. While the impact of this process on the sensory input has been studied, little is known about how sensory input causes this change in the motor pattern. Here, using high-speed imaging of whisking in mice, we simultaneously measured whisker contacts and the resulting whisking motion. We found that mice precisely target their whisker protractions to the distance at which they expect objects. This modulation does not depend on the current sensory input and remains stable for at least one whisking cycle when there is no object contact or when the object position is changed. As a result, the timing and other information carried by whisker contacts encodes how well each protraction was matched to the object, functioning as an error signal. Whisker contacts can thus encode a mismatch between expected object locations and the actual environment.
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Affiliation(s)
- Jakob Voigts
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts; Laboratory of Neural Circuits and Plasticity, USC, Los Angeles, California
| | - David H Herman
- Laboratory of Neural Circuits and Plasticity, USC, Los Angeles, California; Neuroscience Graduate Program, USC, Los Angeles, California; and
| | - Tansu Celikel
- Donders Centre for Neuroscience, Department of Neurophysiology, Nijmegen, The Netherlands
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34
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Modeling forces and moments at the base of a rat vibrissa during noncontact whisking and whisking against an object. J Neurosci 2014; 34:9828-44. [PMID: 25057187 DOI: 10.1523/jneurosci.1707-12.2014] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
During exploratory behavior, rats brush and tap their whiskers against objects, and the mechanical signals so generated constitute the primary sensory variables upon which these animals base their vibrissotactile perception of the world. To date, however, we lack a general dynamic model of the vibrissa that includes the effects of inertia, damping, and collisions. We simulated vibrissal dynamics to compute the time-varying forces and bending moment at the vibrissa base during both noncontact (free-air) whisking and whisking against an object (collision). Results show the following: (1) during noncontact whisking, mechanical signals contain components at both the whisking frequency and also twice the whisking frequency (the latter could code whisking speed); (2) when rats whisk rhythmically against an object, the intrinsic dynamics of the vibrissa can be as large as many of the mechanical effects of the collision, however, the axial force could still generate responses that reliably indicate collision based on thresholding; and (3) whisking velocity will have only a small effect on the transient response generated during a whisker-object collision. Instead, the transient response will depend in large part on how the rat chooses to decelerate its vibrissae after the collision. The model allows experimentalists to estimate error bounds on quasi-static descriptions of vibrissal shape, and its predictions can be used to bound realistic expectations from neurons that code vibrissal sensing. We discuss the implications of these results under the assumption that primary sensory neurons of the trigeminal ganglion are sensitive to various combinations of mechanical signals.
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35
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Cerebellum involvement in cortical sensorimotor circuits for the control of voluntary movements. Nat Neurosci 2014; 17:1233-9. [PMID: 25064850 DOI: 10.1038/nn.3773] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/02/2014] [Indexed: 11/08/2022]
Abstract
Sensorimotor integration is crucial to perception and motor control. How and where this process takes place in the brain is still largely unknown. Here we analyze the cerebellar contribution to sensorimotor integration in the whisker system of mice. We identify an area in the cerebellum where cortical sensory and motor inputs converge at the cellular level. Optogenetic stimulation of this area affects thalamic and motor cortex activity, alters parameters of ongoing movements and thereby modifies qualitatively and quantitatively touch events against surrounding objects. These results shed light on the cerebellum as an active component of sensorimotor circuits and show the importance of sensorimotor cortico-cerebellar loops in the fine control of voluntary movements.
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36
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Optogenetic patterning of whisker-barrel cortical system in transgenic rat expressing channelrhodopsin-2. PLoS One 2014; 9:e93706. [PMID: 24695456 PMCID: PMC3973546 DOI: 10.1371/journal.pone.0093706] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 03/05/2014] [Indexed: 01/03/2023] Open
Abstract
The rodent whisker-barrel system has been an ideal model for studying somatosensory representations in the cortex. However, it remains a challenge to experimentally stimulate whiskers with a given pattern under spatiotemporal precision. Recently the optogenetic manipulation of neuronal activity has made possible the analysis of the neuronal network with precise spatiotemporal resolution. Here we identified the selective expression of channelrhodopsin-2 (ChR2), an algal light-driven cation channel, in the large mechanoreceptive neurons in the trigeminal ganglion (TG) as well as their peripheral nerve endings innervating the whisker follicles of a transgenic rat. The spatiotemporal pattern of whisker irradiation thus produced a barrel-cortical response with a specific spatiotemporal pattern as evidenced by electrophysiological and functional MRI (fMRI) studies. Our methods of generating an optogenetic tactile pattern (OTP) can be expected to facilitate studies on how the spatiotemporal pattern of touch is represented in the somatosensory cortex, as Hubel and Wiesel did in the visual cortex.
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37
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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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Mameli O, Stanzani S, Russo A, Pellitteri R, Manca P, De Riu PL, Caria MA. Involvement of trigeminal mesencephalic nucleus in kinetic encoding of whisker movements. Brain Res Bull 2014; 102:37-45. [PMID: 24518654 DOI: 10.1016/j.brainresbull.2014.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/22/2014] [Accepted: 01/31/2014] [Indexed: 01/02/2023]
Abstract
In previous experiments performed on anaesthetised rats, we demonstrated that whisking neurons responsive to spontaneous movement of the macrovibrissae are located within the trigeminal mesencephalic nucleus (Me5) and that retrograde tracers injected into the mystacial pad of the rat muzzle extensively labelled a number of Me5 neurons. In order to evaluate the electrophysiological characteristics of the Me5-whisker pad neural connection, the present study analysed the Me5 neurons responses to artificial whisking induced by electrical stimulation of the peripheral stump of the facial nerve. Furthermore, an anterograde tracer was injected into the Me5 to identify and localise the peripheral terminals of these neurons in the mystacial structures. The electrophysiological data demonstrated that artificial whisking induced Me5 evoked potentials as well as single and multiunit Me5 neurons responses consistent with a direct connection. Furthermore, the neuroanatomical findings showed that the peripheral terminals of the Me5 stained neurons established direct connections with the upper part of the macrovibrissae, at the conical body level, with fibres spiralling around the circumference of the vibrissae shaft. As for the functional role of this sensory innervation, we speculated that the Me5 neurons are possibly involved in encoding and relaying proprioceptive information related to vibrissae movements to other CNS structures.
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Affiliation(s)
- Ombretta Mameli
- Department of Clinical and Experimental Medicine, Human Physiology, School of Medicine, Sassari University, viale San Pietro 8, 07100 Sassari, Italy.
| | - Stefania Stanzani
- Department of Biomedical Sciences, Physiology Division, Catania University, 95125 Catania, Italy
| | - Antonella Russo
- Department of Biomedical Sciences, Physiology Division, Catania University, 95125 Catania, Italy
| | - Rosalia Pellitteri
- Institute of Neurological Sciences, National Research Council, Section of Catania, 95125 Catania, Italy
| | - Paolo Manca
- Department of Clinical and Experimental Medicine, Human Physiology, School of Medicine, Sassari University, viale San Pietro 8, 07100 Sassari, Italy
| | - Pier Luigi De Riu
- Department of Clinical and Experimental Medicine, Human Physiology, School of Medicine, Sassari University, viale San Pietro 8, 07100 Sassari, Italy
| | - Marcello Alessandro Caria
- Department of Clinical and Experimental Medicine, Human Physiology, School of Medicine, Sassari University, viale San Pietro 8, 07100 Sassari, Italy
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Panzeri S, Ince RAA, Diamond ME, Kayser C. Reading spike timing without a clock: intrinsic decoding of spike trains. Philos Trans R Soc Lond B Biol Sci 2014; 369:20120467. [PMID: 24446501 PMCID: PMC3895992 DOI: 10.1098/rstb.2012.0467] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The precise timing of action potentials of sensory neurons relative to the time of stimulus presentation carries substantial sensory information that is lost or degraded when these responses are summed over longer time windows. However, it is unclear whether and how downstream networks can access information in precise time-varying neural responses. Here, we review approaches to test the hypothesis that the activity of neural populations provides the temporal reference frames needed to decode temporal spike patterns. These approaches are based on comparing the single-trial stimulus discriminability obtained from neural codes defined with respect to network-intrinsic reference frames to the discriminability obtained from codes defined relative to the experimenter's computer clock. Application of this formalism to auditory, visual and somatosensory data shows that information carried by millisecond-scale spike times can be decoded robustly even with little or no independent external knowledge of stimulus time. In cortex, key components of such intrinsic temporal reference frames include dedicated neural populations that signal stimulus onset with reliable and precise latencies, and low-frequency oscillations that can serve as reference for partitioning extended neuronal responses into informative spike patterns.
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Affiliation(s)
- Stefano Panzeri
- Institute of Neuroscience and Psychology, University of Glasgow, , Glasgow G12 8QB, UK
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40
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Sherman D, Oram T, Deutsch D, Gordon G, Ahissar E, Harel D. Tactile modulation of whisking via the brainstem loop: statechart modeling and experimental validation. PLoS One 2013; 8:e79831. [PMID: 24312186 PMCID: PMC3842298 DOI: 10.1371/journal.pone.0079831] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/25/2013] [Indexed: 11/18/2022] Open
Abstract
Rats repeatedly sweep their facial whiskers back and forth in order to explore their environment. Such explorative whisking appears to be driven by central pattern generators (CPGs) that operate independently of direct sensory feedback. Nevertheless, whisking can be modulated by sensory feedback, and it has been hypothesized that some of this modulation already occurs within the brainstem. However, the interaction between sensory feedback and CPG activity is poorly understood. Using the visual language of statecharts, a dynamic, bottom-up computerized model of the brainstem loop of the whisking system was built in order to investigate the interaction between sensory feedback and CPG activity during whisking behavior. As a benchmark, we used a previously quantified closed-loop phenomenon of the whisking system, touched-induced pump (TIP), which is thought to be mediated by the brainstem loop. First, we showed that TIPs depend on sensory feedback, by comparing TIP occurrence in intact rats with that in rats whose sensory nerve was experimentally cut. We then inspected several possible feedback mechanisms of TIPs using our model. The model ruled out all hypothesized mechanisms but one, which adequately simulated the corresponding motion observed in the rat. Results of the simulations suggest that TIPs are generated via sensory feedback that activates extrinsic retractor muscles in the mystacial pad. The model further predicted that in addition to the touching whisker, all whiskers found on the same side of the snout should exhibit a TIP. We present experimental results that confirm the predicted movements in behaving rats, establishing the validity of the hypothesized interaction between sensory feedback and CPG activity we suggest here for the generation of TIPs in the whisking system.
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Affiliation(s)
- Dana Sherman
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel ; Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel
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41
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Ahissar E, Oram T. Thalamic Relay or Cortico-Thalamic Processing? Old Question, New Answers. Cereb Cortex 2013; 25:845-8. [DOI: 10.1093/cercor/bht296] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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42
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Mitchinson B, Prescott TJ. Whisker movements reveal spatial attention: a unified computational model of active sensing control in the rat. PLoS Comput Biol 2013; 9:e1003236. [PMID: 24086120 PMCID: PMC3784505 DOI: 10.1371/journal.pcbi.1003236] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 08/08/2013] [Indexed: 11/19/2022] Open
Abstract
Spatial attention is most often investigated in the visual modality through measurement of eye movements, with primates, including humans, a widely-studied model. Its study in laboratory rodents, such as mice and rats, requires different techniques, owing to the lack of a visual fovea and the particular ethological relevance of orienting movements of the snout and the whiskers in these animals. In recent years, several reliable relationships have been observed between environmental and behavioural variables and movements of the whiskers, but the function of these responses, as well as how they integrate, remains unclear. Here, we propose a unifying abstract model of whisker movement control that has as its key variable the region of space that is the animal's current focus of attention, and demonstrate, using computer-simulated behavioral experiments, that the model is consistent with a broad range of experimental observations. A core hypothesis is that the rat explicitly decodes the location in space of whisker contacts and that this representation is used to regulate whisker drive signals. This proposition stands in contrast to earlier proposals that the modulation of whisker movement during exploration is mediated primarily by reflex loops. We go on to argue that the superior colliculus is a candidate neural substrate for the siting of a head-centred map guiding whisker movement, in analogy to current models of visual attention. The proposed model has the potential to offer a more complete understanding of whisker control as well as to highlight the potential of the rodent and its whiskers as a tool for the study of mammalian attention.
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Affiliation(s)
- Ben Mitchinson
- Department Of Psychology, The University Of Sheffield, Sheffield, United Kingdom
| | - Tony J. Prescott
- Department Of Psychology, The University Of Sheffield, Sheffield, United Kingdom
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43
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Yu C, Horev G, Rubin N, Derdikman D, Haidarliu S, Ahissar E. Coding of object location in the vibrissal thalamocortical system. ACTA ACUST UNITED AC 2013; 25:563-77. [PMID: 24062318 DOI: 10.1093/cercor/bht241] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In whisking rodents, object location is encoded at the receptor level by a combination of motor and sensory related signals. Recoding of the encoded signals can result in various forms of internal representations. Here, we examined the coding schemes occurring at the first forebrain level that receives inputs necessary for generating such internal representations--the thalamocortical network. Single units were recorded in 8 thalamic and cortical stations in artificially whisking anesthetized rats. Neuronal representations of object location generated across these stations and expressed in response latency and magnitude were classified based on graded and binary coding schemes. Both graded and binary coding schemes occurred across the entire thalamocortical network, with a general tendency of graded-to-binary transformation from thalamus to cortex. Overall, 63% of the neurons of the thalamocortical network coded object position in their firing. Thalamocortical responses exhibited a slow dynamics during which the amount of coded information increased across 4-5 whisking cycles and then stabilized. Taken together, the results indicate that the thalamocortical network contains dynamic mechanisms that can converge over time on multiple coding schemes of object location, schemes which essentially transform temporal coding to rate coding and gradual to labeled-line coding.
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Affiliation(s)
- Chunxiu Yu
- Current address: Department of Psychology and Neuroscience, Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA
| | - Guy Horev
- Current address: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Naama Rubin
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel Current address: Department of Psychology and Neuroscience, Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA Current address: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Dori Derdikman
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel Current address: Department of Psychology and Neuroscience, Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA Current address: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Sebastian Haidarliu
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel Current address: Department of Psychology and Neuroscience, Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA Current address: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Ehud Ahissar
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel Current address: Department of Psychology and Neuroscience, Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA Current address: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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44
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O'Connor DH, Hires SA, Guo ZV, Li N, Yu J, Sun QQ, Huber D, Svoboda K. Neural coding during active somatosensation revealed using illusory touch. Nat Neurosci 2013; 16:958-65. [PMID: 23727820 PMCID: PMC3695000 DOI: 10.1038/nn.3419] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/05/2013] [Indexed: 12/14/2022]
Abstract
Active sensation requires the convergence of external stimuli with representations of body movements. We used mouse behavior, electrophysiology and optogenetics to dissect the temporal interactions among whisker movement, neural activity and sensation of touch. We photostimulated layer 4 activity in single barrels in a closed loop with whisking. Mimicking touch-related neural activity caused illusory perception of an object at a particular location, but scrambling the timing of the spikes over one whisking cycle (tens of milliseconds) did not abolish the illusion, indicating that knowledge of instantaneous whisker position is unnecessary for discriminating object locations. The illusions were induced only during bouts of directed whisking, when mice expected touch, and in the relevant barrel. Reducing activity biased behavior, consistent with a spike count code for object detection at a particular location. Our results show that mice integrate coding of touch with movement over timescales of a whisking bout to produce perception of active touch.
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Affiliation(s)
- Daniel H O'Connor
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
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45
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Abstract
Rodents move their whiskers to locate objects in space. Here we used psychophysical methods to show that head-fixed mice can localize objects along the axis of a single whisker, the radial dimension, with one-millimeter precision. High-speed videography allowed us to estimate the forces and bending moments at the base of the whisker, which underlie radial distance measurement. Mice judged radial object location based on multiple touches. Both the number of touches (1-17) and the forces exerted by the pole on the whisker (up to 573 μN; typical peak amplitude, 100 μN) varied greatly across trials. We manipulated the bending moment and lateral force pressing the whisker against the sides of the follicle and the axial force pushing the whisker into the follicle by varying the compliance of the object during behavior. The behavioral responses suggest that mice use multiple variables (bending moment, axial force, lateral force) to extract radial object localization. Characterization of whisker mechanics revealed that whisker bending stiffness decreases gradually with distance from the face over five orders of magnitude. As a result, the relative amplitudes of different stress variables change dramatically with radial object distance. Our data suggest that mice use distance-dependent whisker mechanics to estimate radial object location using an algorithm that does not rely on precise control of whisking, is robust to variability in whisker forces, and is independent of object compliance and object movement. More generally, our data imply that mice can measure the amplitudes of forces in the sensory follicles for tactile sensation.
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46
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Pre-neuronal morphological processing of object location by individual whiskers. Nat Neurosci 2013; 16:622-31. [PMID: 23563582 DOI: 10.1038/nn.3378] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 03/11/2013] [Indexed: 11/08/2022]
Abstract
In the vibrissal system, touch information is conveyed by a receptorless whisker hair to follicle mechanoreceptors, which then provide input to the brain. We examined whether any processing, that is, meaningful transformation, occurs in the whisker itself. Using high-speed videography and tracking the movements of whiskers in anesthetized and behaving rats, we found that whisker-related morphological phase planes, based on angular and curvature variables, can represent the coordinates of object position after contact in a reliable manner, consistent with theoretical predictions. By tracking exposed follicles, we found that the follicle-whisker junction is rigid, which enables direct readout of whisker morphological coding by mechanoreceptors. Finally, we found that our behaving rats pushed their whiskers against objects during localization in a way that induced meaningful morphological coding and, in parallel, improved their localization performance, which suggests a role for pre-neuronal morphological computation in active vibrissal touch.
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Abstract
Perception involves motor control of sensory organs. However, the dynamics underlying emergence of perception from motor-sensory interactions are not yet known. Two extreme possibilities are as follows: (1) motor and sensory signals interact within an open-loop scheme in which motor signals determine sensory sampling but are not affected by sensory processing and (2) motor and sensory signals are affected by each other within a closed-loop scheme. We studied the scheme of motor-sensory interactions in humans using a novel object localization task that enabled monitoring the relevant overt motor and sensory variables. We found that motor variables were dynamically controlled within each perceptual trial, such that they gradually converged to steady values. Training on this task resulted in improvement in perceptual acuity, which was achieved solely by changes in motor variables, without any change in the acuity of sensory readout. The within-trial dynamics is captured by a hierarchical closed-loop model in which lower loops actively maintain constant sensory coding, and higher loops maintain constant sensory update flow. These findings demonstrate interchangeability of motor and sensory variables in perception, motor convergence during perception, and a consistent hierarchical closed-loop perceptual model.
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48
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Sense, memory, and decision-making in the somatosensory cortical network. Curr Opin Neurobiol 2012; 22:914-9. [PMID: 22939031 DOI: 10.1016/j.conb.2012.08.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 08/04/2012] [Accepted: 08/12/2012] [Indexed: 11/23/2022]
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Boubenec Y, Shulz DE, Debrégeas G. Whisker encoding of mechanical events during active tactile exploration. Front Behav Neurosci 2012; 6:74. [PMID: 23133410 PMCID: PMC3490139 DOI: 10.3389/fnbeh.2012.00074] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 10/18/2012] [Indexed: 11/23/2022] Open
Abstract
Rats use their whiskers to extract a wealth of information about their immediate environment, such as the shape, position or texture of an object. The information is conveyed to mechanoreceptors located within the whisker follicle in the form of a sequence of whisker deflections induced by the whisker/object contact interaction. How the whiskers filter and shape the mechanical information and effectively participate in the coding of tactile features remains an open question to date. In the present article, a biomechanical model was developed that provides predictions of the whisker dynamics during active tactile exploration, amenable to quantitative experimental comparison. This model is based on a decomposition of the whisker profile into a slow, quasi-static sequence and rapid resonant small-scale vibrations. It was applied to the typical situation of a rat actively whisking across a solid object. Having derived the quasi-static sequence of whisker deformation, the resonant properties of the whisker were analyzed, taking into account the boundary conditions imposed by the whisker/surface contact. We then focused on two elementary mechanical events that are expected to trigger significant neural responses, namely (1) the whisker/object first contact and (2) the whisker detachment from the object. Both events were found to trigger a deflection wave propagating upward to the mystacial pad at constant velocity of ≈3–5 m/s. This yielded a characteristic mechanical signature at the whisker base, in the form of a large peak of negative curvature occurring ≈4 ms after the event has been triggered. The dependence in amplitude and lag of this mechanical signal with the main contextual parameters (such as radial or angular distance) was investigated. The model was validated experimentally by comparing its predictions to high-speed video recordings of shock-induced whisker deflections performed on anesthetized rats. The consequences of these results on possible tactile encoding schemes are briefly discussed.
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Affiliation(s)
- Yves Boubenec
- Unité de Neurosciences Information et Complexité, UPR 3293, Centre National de la Recherche Scientifique Gif-sur-Yvette, France
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Petreanu L, Gutnisky DA, Huber D, Xu NL, O'Connor DH, Tian L, Looger L, Svoboda K. Activity in motor-sensory projections reveals distributed coding in somatosensation. Nature 2012; 489:299-303. [PMID: 22922646 PMCID: PMC3443316 DOI: 10.1038/nature11321] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 06/12/2012] [Indexed: 11/09/2022]
Abstract
Cortical feed-back projections to primary sensory areas terminate most heavily in layer (L) 11,2, where they make synapses with tuft dendrites of pyramidal neurons. L1 input is thought to provide ‘contextual’ information3, but the signals transmitted by L1 feedback remain uncharacterized. In the rodent somatosensory system, the spatially diffuse4 vibrissal motor cortex (vM1)→ vibrissal somatosensory cortex (barrel cortex, vS1) feedback projection may allow whisker touch to be interpreted in the context of whisker position to compute object location5,6. When mice palpate objects with their whiskers to localize object features7,8, whisker touch excites vibrissal somatosensory cortex (barrel cortex, vS1)9 and later vibrissal motor cortex (vM1) in a somatotopic manner10,11,12,13. Here we used axonal calcium imaging to track activity in vM1→ vS1 afferents in L1 of barrel cortex, while mice performed whisker-dependent object localization. Spatially intermingled individual axons represented whisker movements, touch, and other behavioral features. In a subpopulation of axons, activity depended on object location and persisted for seconds after touch. Neurons in the barrel cortex thus have information to integrate movements and touches of multiple whiskers over time, key components of object identification and navigation by active touch.
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Affiliation(s)
- Leopoldo Petreanu
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, USA
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