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Linen SR, Chang NH, Hess EJ, Stanley GB, Waiblinger C. The 6-OHDA Parkinson's Disease Mouse Model Shows Deficits in Sensory Behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2024.06.05.597339. [PMID: 38895263 PMCID: PMC11185599 DOI: 10.1101/2024.06.05.597339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Parkinson's disease (PD) is characterized by the degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta, leading to dopamine depletion in the striatum and the hallmark motor symptoms of the disease. However, non-motor deficits, particularly sensory symptoms, often precede motor manifestations, offering a potential early diagnostic window. The impact of non-motor deficits on sensation behavior and the underlying mechanisms remain poorly understood. In this study, we examined changes in tactile sensation within a parkinsonian state by employing a mouse model of PD induced by 6-hydroxydopamine (6-OHDA) to deplete striatal DA. Leveraging the conserved mouse whisker system as a model for tactile-sensory stimulation, we conducted psychophysical experiments to assess sensory-driven behavioral performance during a tactile detection task in both the healthy and PD-like state. Our findings reveal a range of deficits across subjects following 6-OHDA lesion, including DA loss, motor asymmetry, weight loss, and varying levels of altered tactile sensation behavior. Behavioral changes ranged from no impairments in minor cases to isolated sensory-behavioral deficits in moderate cases and severe motor dysfunction in advanced stages. These results underscore the complex relationship between DA imbalance and sensory-motor processing, emphasizing the need for precise and multifaceted behavioral measurements to accurately capture the diverse manifestations of PD.
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Affiliation(s)
- Savannah R. Linen
- Program in Bioinformatics, Georgia Institute of Technology, Atlanta, GA, USA
| | - Nelson H. Chang
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Ellen J. Hess
- Departments of Pharmacology and Chemical Biology and Neurology, Emory University, Atlanta, GA USA
| | - Garrett B. Stanley
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Christian Waiblinger
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
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2
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Sharma H, Azouz R. Reliability and stability of tactile perception in the whisker somatosensory system. Front Neurosci 2024; 18:1344758. [PMID: 38872944 PMCID: PMC11169650 DOI: 10.3389/fnins.2024.1344758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 05/14/2024] [Indexed: 06/15/2024] Open
Abstract
Rodents rely on their whiskers as vital sensory tools for tactile perception, enabling them to distinguish textures and shapes. Ensuring the reliability and constancy of tactile perception under varying stimulus conditions remains a fascinating and fundamental inquiry. This study explores the impact of stimulus configurations, including whisker movement velocity and object spatial proximity, on texture discrimination and stability in rats. To address this issue, we employed three distinct approaches for our investigation. Stimulus configurations notably affected tactile inputs, altering whisker vibration's kinetic and kinematic aspects with consistent effects across various textures. Through a texture discrimination task, rats exhibited consistent discrimination performance irrespective of changes in stimulus configuration. However, alterations in stimulus configuration significantly affected the rats' ability to maintain stability in texture perception. Additionally, we investigated the influence of stimulus configurations on cortical neuronal responses by manipulating them experimentally. Notably, cortical neurons demonstrated substantial and intricate changes in firing rates without compromising the ability to discriminate between textures. Nevertheless, these changes resulted in a reduction in texture neuronal response stability. Stimulating multiple whiskers led to improved neuronal texture discrimination and maintained coding stability. These findings emphasize the importance of considering numerous factors and their interactions when studying the impact of stimulus configuration on neuronal responses and behavior.
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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, Israel
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3
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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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4
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Li C, Liao X, Peng ZK, Meng G, He Q. Highly sensitive and broadband meta-mechanoreceptor via mechanical frequency-division multiplexing. Nat Commun 2023; 14:5482. [PMID: 37673899 PMCID: PMC10482866 DOI: 10.1038/s41467-023-41222-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 08/25/2023] [Indexed: 09/08/2023] Open
Abstract
Bio-mechanoreceptors capable of micro-motion sensing have inspired mechanics-guided designs of micro-motion sensors in various fields. However, it remains a major challenge for mechanics-guided designs to simultaneously achieve high sensitivity and broadband sensing due to the nature of resonance effect. By mimicking rat vibrissae, here we report a metamaterial mechanoreceptor (MMR) comprised of piezoelectric resonators with distributed zero effective masses featuring a broad range of local resonances, leading to near-infinite sensitivity for micro-motion sensing within a broad bandwidth. We developed a mechanical frequency-division multiplexing mechanism for MMR, in which the measured micro-motion signal is mechanically modulated in non-overlapping frequency bands and reconstructed by a computational multi-channel demodulation approach. The maximum sensitivity of MMR is improved by two orders of magnitude compared to conventional mechanics-guided mechanoreceptors, and its bandwidth with high sensitivity is extendable towards both low-frequency and high-frequency ranges in 0-12 kHz through tuning the local resonance of each individual sensing cell. The MMR is a promising candidate for highly sensitive and broadband micro-motion sensing that was previously inaccessible for mechanics-guided mechanoreceptors, opening pathways towards spatio-temporal sensing, remote-vibration monitoring and smart-driving assistance.
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Affiliation(s)
- Chong Li
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Xinxin Liao
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Zhi-Ke Peng
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
- School of Mechanical Engineering, Ningxia University, Yinchuan, 750021, P. R. China
| | - Guang Meng
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Qingbo He
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
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5
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Ding Y, Vlasov Y. Pre-neuronal processing of haptic sensory cues via dispersive high-frequency vibrational modes. Sci Rep 2023; 13:14370. [PMID: 37658126 PMCID: PMC10474056 DOI: 10.1038/s41598-023-40675-8] [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: 02/05/2023] [Accepted: 08/16/2023] [Indexed: 09/03/2023] Open
Abstract
Sense of touch is one of the major perception channels. Neural coding of object textures conveyed by rodents' whiskers has been a model to study early stages of haptic information uptake. While high-precision spike timing has been observed during whisker sweeping across textured surfaces, the exact nature of whisker micromotions that spikes encode remains elusive. Here, we discovered that a single micro-collision of a whisker with surface features generates vibrational eigenmodes spanning frequencies up to 10 kHz. While propagating along the whisker, these high-frequency modes can carry up to 80% of shockwave energy, exhibit 100× smaller damping ratio, and arrive at the follicle 10× faster than low frequency components. The mechano-transduction of these energy bursts into time-sequenced population spike trains may generate temporally unique "bar code" with ultra-high information capacity. This hypothesis of pre-neuronal processing of haptic signals based on dispersive temporal separation of the vibrational modal frequencies can shed light on neural coding of haptic signals in many whisker-like sensory organs across the animal world as well as in texture perception in primate's glabrous skin.
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Affiliation(s)
- Yu Ding
- Department of Physics, University of Illinois Urbana Champaign, 208 North Wright Street, Urbana, IL, 61801, USA
| | - Yurii Vlasov
- Department of Physics, University of Illinois Urbana Champaign, 208 North Wright Street, Urbana, IL, 61801, USA.
- Department of BioEngineering, University of Illinois Urbana Champaign, 208 North Wright Street, Urbana, IL, 61801, USA.
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, 208 North Wright Street, Urbana, IL, 61801, USA.
- Department of Electrical and Computer Engineering, University of Illinois Urbana Champaign, 208 North Wright Street, Urbana, IL, 61801, USA.
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6
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Schoenberger JM, Prendergast BJ, Luchins KR, Theriault BR, Langan GP. Preference of Escaped Mice for Live Capture or Glue Traps and Relevance to Pest Control Programs. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2023; 62:38-47. [PMID: 36755208 PMCID: PMC9936854 DOI: 10.30802/aalas-jaalas-22-000073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Insects are potential disease vectors for research animals. Therefore, implementing an effective pest control program is an essential component of any animal care and use program. The Guide for the Care and Use of Laboratory Animals emphasizes the humane use of traps; however, insect traps commonly use glue that can entrap escaped research mice, leading to their potential distress and injury. This situation is challenging for research facilities attempting to identify insect populations. In an effort to improve pest control in animal facilities, we sought to characterize the behavioral interactions of mice with common vermin traps. Three experiments using different combinations of traps (glue trap, live mouse trap with a clear viewing window, and live mouse trap with a red-tinted viewing window) were used in multiple behavioral testing arenas to address these questions. Experiments 1 and 2 were performed in a small arena, and Experiment 3 was performed in a simulated mouse housing room. Dependent measures included exploration of the test environment, grooming behavior, time spent near each trap, and latency to capture. Results indicate that mice were captured significantly more quickly by live traps than by glue traps, and were far more likely to enter a live trap as compared with a glue trap. Mice did not appear to differentiate between clear or red-tinted window live traps. Taken together, the results indicate that deploying both a live trap and a glue trap will allow humane capture of escaped mice yet will also capture insects in the same environment.
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7
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Golomb D, Moore JD, Fassihi A, Takatoh J, Prevosto V, Wang F, Kleinfeld D. Theory of hierarchically organized neuronal oscillator dynamics that mediate rodent rhythmic whisking. Neuron 2022; 110:3833-3851.e22. [PMID: 36113472 PMCID: PMC10248719 DOI: 10.1016/j.neuron.2022.08.020] [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: 01/21/2022] [Revised: 07/06/2022] [Accepted: 08/17/2022] [Indexed: 12/15/2022]
Abstract
Rodents explore their environment through coordinated orofacial motor actions, including whisking. Whisking can free-run via an oscillator of inhibitory neurons in the medulla and can be paced by breathing. Yet, the mechanics of the whisking oscillator and its interaction with breathing remain to be understood. We formulate and solve a hierarchical model of the whisking circuit. The first whisk within a breathing cycle is generated by inhalation, which resets a vibrissa oscillator circuit, while subsequent whisks are derived from the oscillator circuit. Our model posits, consistent with experiment, that there are two subpopulations of oscillator neurons. Stronger connections between the subpopulations support rhythmicity, while connections within each subpopulation induce variable spike timing that enhances the dynamic range of rhythm generation. Calculated cycle-to-cycle changes in whisking are consistent with experiment. Our model provides a computational framework to support longstanding observations of concurrent autonomous and driven rhythmic motor actions that comprise behaviors.
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Affiliation(s)
- David Golomb
- Department of Physiology and Cell Biology, Ben Gurion University, Be'er-Sheva 8410501, Israel; Department of Physics, Ben Gurion University, Be'er-Sheva 8410501, Israel; Zlotowski Center for Neuroscience, Ben Gurion University, Be'er-Sheva 8410501, Israel.
| | - Jeffrey D Moore
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Arash Fassihi
- Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA
| | - Jun Takatoh
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Vincent Prevosto
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Fan Wang
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; McGovern Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - David Kleinfeld
- Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA; Department of Neurobiology, University of California at San Diego, La Jolla, CA 92093, USA.
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8
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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: 0.3] [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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9
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Bhattacharjee A, Schwarz C. Temporally Local Tactile Codes Can Be Stored in Working Memory. Front Hum Neurosci 2022; 16:840108. [PMID: 35712533 PMCID: PMC9195853 DOI: 10.3389/fnhum.2022.840108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 05/04/2022] [Indexed: 11/13/2022] Open
Abstract
Tactile exploration often involves sequential touches interspersed with stimulus-free durations (e.g., the time during which the hand moves from one textured surface to the other). Whereas it is obvious that texture-related perceptual variables, irrespective of the encoding strategy, must be stored in memory for comparison, it is rather unclear which of those variables are held in memory. There are two established variables—“intensity” and “frequency”, which are “temporally global” variables because of the long stimulus integration interval required to average the signal or derive spectral components, respectively; on the other hand, a recently established third contender is the “temporally local” variable that codes for kinematic profiles of very short, suprathreshold events in the vibrotactile signal. Here, we present the first psychophysical evidence that temporally local variables can be stored in memory. To that end, we asked participants to detect changes in pulsatile indentation stimuli at their fingertips with and without a gap of 1 s between stimulus presentations. The stimuli either contained global variables alone (change of pulse rate), or a mix of local and global variables (change of pulse shape). We found, first, that humans are much better at detecting a change in stimuli when local variables are available rather than global ones alone—as evident by the fact that 21 compared to only 6 participants out of 25 yielded a valid psychophysical curve, respectively. Second, this observation persists even when there is a gap between the stimuli, implying local variables must be stored in memory. Third, an extensive array of relevant intensity definitions failed to explain participants’ performance in any consistent manner, which implies that perceptual decisions were less likely to be driven by intensity coding. Taken together, our results suggest that humans perform pulsatile change detection utilizing local pulse shape, and to a lesser degree global pulse rate, and that both parameters can be stored in memory.
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Affiliation(s)
- Arindam Bhattacharjee
- Werner Reichardt Center for Integrative Neuroscience, Systems Neuroscience, Eberhard Karls University Tübingen, Tübingen, Germany
- Hertie Institute for Clinical Brain Research, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Cornelius Schwarz
- Werner Reichardt Center for Integrative Neuroscience, Systems Neuroscience, Eberhard Karls University Tübingen, Tübingen, Germany
- Hertie Institute for Clinical Brain Research, Eberhard Karls University Tübingen, Tübingen, Germany
- *Correspondence: Cornelius Schwarz
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10
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Waiblinger C, McDonnell ME, Reedy AR, Borden PY, Stanley GB. Emerging experience-dependent dynamics in primary somatosensory cortex reflect behavioral adaptation. Nat Commun 2022; 13:534. [PMID: 35087056 PMCID: PMC8795122 DOI: 10.1038/s41467-022-28193-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 01/05/2022] [Indexed: 11/09/2022] Open
Abstract
Behavioral experience and flexibility are crucial for survival in a constantly changing environment. Despite evolutionary pressures to develop adaptive behavioral strategies in a dynamically changing sensory landscape, the underlying neural correlates have not been well explored. Here, we use genetically encoded voltage imaging to measure signals in primary somatosensory cortex (S1) during sensory learning and behavioral adaptation in the mouse. In response to changing stimulus statistics, mice adopt a strategy that modifies their detection behavior in a context dependent manner as to maintain reward expectation. Surprisingly, neuronal activity in S1 shifts from simply representing stimulus properties to transducing signals necessary for adaptive behavior in an experience dependent manner. Our results suggest that neuronal signals in S1 are part of an adaptive framework that facilitates flexible behavior as individuals gain experience, which could be part of a general scheme that dynamically distributes the neural correlates of behavior during learning. Waiblinger et al. investigate the role of primary sensory cortex in flexible behaviors. They show that neuronal signals in S1 are part of an adaptive and dynamic framework that facilitates flexible behavior as an individual gains experience, indicating a role for S1 in long-term adaptive strategies.
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Affiliation(s)
- Christian Waiblinger
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Megan E McDonnell
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - April R Reedy
- Integrated Cellular Imaging Core, Emory University School of Medicine, Emory University, Atlanta, GA, USA
| | - Peter Y Borden
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Garrett B Stanley
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
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11
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Humans Use a Temporally Local Code for Vibrotactile Perception. eNeuro 2021; 8:ENEURO.0263-21.2021. [PMID: 34625459 PMCID: PMC8570683 DOI: 10.1523/eneuro.0263-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/19/2021] [Accepted: 08/22/2021] [Indexed: 11/21/2022] Open
Abstract
Sensory environments are commonly characterized by specific physical features, which sensory systems might exploit using dedicated processing mechanisms. In the tactile sense, one such characteristic feature is frictional movement, which gives rise to short-lasting (<10 ms), information-carrying integument vibrations. Rather than generic integrative encoding (i.e., averaging or spectral analysis capturing the "intensity" and "best frequency"), the tactile system might benefit from, what we call a "temporally local" coding scheme that instantaneously detects and analyzes shapes of these short-lasting features. Here, by employing analytic psychophysical measurements, we tested whether the prerequisite of temporally local coding exists in the human tactile system. We employed pulsatile skin indentations at the fingertip that allowed us to trade manipulation of local pulse shape against changes in global intensity and frequency, achieved by adding pulses of the same shape. We found that manipulation of local pulse shape has strong effects on psychophysical performance, arguing for the notion that humans implement a temporally local coding scheme for perceptual decisions. As we found distinct differences in performance using different kinematic layouts of pulses, we inquired whether temporally local coding is tuned to a unique kinematic variable. This was not the case, since we observed different preferred kinematic variables in different ranges of pulse shapes. Using an established encoding model for primary afferences and indentation stimuli, we were able to demonstrate that the found kinematic preferences in human performance, may well be explained by the response characteristics of Pacinian corpuscles (PCs), a class of human tactile primary afferents.
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12
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Kirsch LP, Job XE, Auvray M, Hayward V. Harnessing tactile waves to measure skin-to-skin interactions. Behav Res Methods 2021; 53:1469-1477. [PMID: 33205350 DOI: 10.3758/s13428-020-01492-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2020] [Indexed: 01/02/2023]
Abstract
Skin-to-skin touch is an essential form of tactile interaction, yet there is no known method to quantify how we touch our own skin or someone else's skin. Skin-to-skin touch is particularly challenging to measure objectively, since interposing an instrumented sheet, no matter how thin and flexible, between the interacting skins is not an option. To fill this gap, we explored a technique that takes advantage of the propagation of vibrations from the locus of touch to pick up a signal that contains information about skin-to-skin tactile interactions. These "tactile waves" were measured by an accelerometer sensor placed on the touching finger. Applied pressure and speed had a direct influence on measured signal power when the target of touch was the self or another person. The measurements were insensitive to changes in the location of the sensor relative to the target. Our study suggests that this method has potential for probing behaviour during skin-to-skin tactile interactions and could be a valuable technique to study social touch, self-touch, and motor control. The method is non-invasive, easy to commission, inexpensive, and robust.
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Affiliation(s)
- Louise P Kirsch
- Institut des Systèmes Intelligents et de Robotique, Sorbonne Université, 4 place Jussieu, 75005, Paris, France.
| | - Xavier E Job
- Institut des Systèmes Intelligents et de Robotique, Sorbonne Université, 4 place Jussieu, 75005, Paris, France
| | - Malika Auvray
- Institut des Systèmes Intelligents et de Robotique, Sorbonne Université, 4 place Jussieu, 75005, Paris, France
| | - Vincent Hayward
- Institut des Systèmes Intelligents et de Robotique, Sorbonne Université, 4 place Jussieu, 75005, Paris, France
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13
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Rodgers CC, Nogueira R, Pil BC, Greeman EA, Park JM, Hong YK, Fusi S, Bruno RM. Sensorimotor strategies and neuronal representations for shape discrimination. Neuron 2021; 109:2308-2325.e10. [PMID: 34133944 PMCID: PMC8298290 DOI: 10.1016/j.neuron.2021.05.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 01/28/2021] [Accepted: 05/14/2021] [Indexed: 10/21/2022]
Abstract
Humans and other animals can identify objects by active touch, requiring the coordination of exploratory motion and tactile sensation. Both the motor strategies and neural representations employed could depend on the subject's goals. We developed a shape discrimination task that challenged head-fixed mice to discriminate concave from convex shapes. Behavioral decoding revealed that mice did this by comparing contacts across whiskers. In contrast, a separate group of mice performing a shape detection task simply summed up contacts over whiskers. We recorded populations of neurons in the barrel cortex, which processes whisker input, and found that individual neurons across the cortical layers encoded touch, whisker motion, and task-related signals. Sensory representations were task-specific: during shape discrimination, but not detection, neurons responded most to behaviorally relevant whiskers, overriding somatotopy. Thus, sensory cortex employs task-specific representations compatible with behaviorally relevant computations.
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Affiliation(s)
- Chris C Rodgers
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.
| | - Ramon Nogueira
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Center for Theoretical Neuroscience, Columbia University, New York, NY 10027, USA
| | - B Christina Pil
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Esther A Greeman
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Jung M Park
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Y Kate Hong
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Stefano Fusi
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA; Center for Theoretical Neuroscience, Columbia University, New York, NY 10027, USA
| | - Randy M Bruno
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.
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14
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Oladazimi M, Putelat T, Szalai R, Noda K, Shimoyama I, Champneys A, Schwarz C. Conveyance of texture signals along a rat whisker. Sci Rep 2021; 11:13570. [PMID: 34193889 PMCID: PMC8245408 DOI: 10.1038/s41598-021-92770-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 06/07/2021] [Indexed: 11/09/2022] Open
Abstract
Neuronal activities underlying a percept are constrained by the physics of sensory signals. In the tactile sense such constraints are frictional stick-slip events, occurring, amongst other vibrotactile features, when tactile sensors are in contact with objects. We reveal new biomechanical phenomena about the transmission of these microNewton forces at the tip of a rat's whisker, where they occur, to the base where they engage primary afferents. Using high resolution videography and accurate measurement of axial and normal forces at the follicle, we show that the conical and curved rat whisker acts as a sign-converting amplification filter for moment to robustly engage primary afferents. Furthermore, we present a model based on geometrically nonlinear Cosserat rod theory and a friction model that recreates the observed whole-beam whisker dynamics. The model quantifies the relation between kinematics (positions and velocities) and dynamic variables (forces and moments). Thus, only videographic assessment of acceleration is required to estimate forces and moments measured by the primary afferents. Our study highlights how sensory systems deal with complex physical constraints of perceptual targets and sensors.
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Affiliation(s)
- Maysam Oladazimi
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Otfried Müller Str. 25, 72076, Tübingen, Germany.,Systems Neurophysiology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Thibaut Putelat
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK.,Department of Sustainable Agriculture Sciences, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Robert Szalai
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK
| | - Kentaro Noda
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan.,Department of Intelligent Robotics, Toyama Prefectural University, Toyama, Japan
| | - Isao Shimoyama
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan.,Toyama Prefectural University, Toyama, Japan
| | - Alan Champneys
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK
| | - Cornelius Schwarz
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Otfried Müller Str. 25, 72076, Tübingen, Germany. .,Systems Neurophysiology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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15
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Wright NC, Borden PY, Liew YJ, Bolus MF, Stoy WM, Forest CR, Stanley GB. Rapid Cortical Adaptation and the Role of Thalamic Synchrony during Wakefulness. J Neurosci 2021; 41:5421-5439. [PMID: 33986072 PMCID: PMC8221593 DOI: 10.1523/jneurosci.3018-20.2021] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/18/2021] [Accepted: 04/29/2021] [Indexed: 12/14/2022] Open
Abstract
Rapid sensory adaptation is observed across all sensory systems, and strongly shapes sensory percepts in complex sensory environments. Yet despite its ubiquity and likely necessity for survival, the mechanistic basis is poorly understood. A wide range of primarily in vitro and anesthetized studies have demonstrated the emergence of adaptation at the level of primary sensory cortex, with only modest signatures in earlier stages of processing. The nature of rapid adaptation and how it shapes sensory representations during wakefulness, and thus the potential role in perceptual adaptation, is underexplored, as are the mechanisms that underlie this phenomenon. To address these knowledge gaps, we recorded spiking activity in primary somatosensory cortex (S1) and the upstream ventral posteromedial (VPm) thalamic nucleus in the vibrissa pathway of awake male and female mice, and quantified responses to whisker stimuli delivered in isolation and embedded in an adapting sensory background. We found that cortical sensory responses were indeed adapted by persistent sensory stimulation; putative excitatory neurons were profoundly adapted, and inhibitory neurons only modestly so. Further optogenetic manipulation experiments and network modeling suggest this largely reflects adaptive changes in synchronous thalamic firing combined with robust engagement of feedforward inhibition, with little contribution from synaptic depression. Taken together, these results suggest that cortical adaptation in the regime explored here results from changes in the timing of thalamic input, and the way in which this differentially impacts cortical excitation and feedforward inhibition, pointing to a prominent role of thalamic gating in rapid adaptation of primary sensory cortex.SIGNIFICANCE STATEMENT Rapid adaptation of sensory activity strongly shapes representations of sensory inputs across all sensory pathways over the timescale of seconds, and has profound effects on sensory perception. Despite its ubiquity and theoretical role in the efficient encoding of complex sensory environments, the mechanistic basis is poorly understood, particularly during wakefulness. In this study in the vibrissa pathway of awake mice, we show that cortical representations of sensory inputs are strongly shaped by rapid adaptation, and that this is mediated primarily by adaptive gating of the thalamic inputs to primary sensory cortex and the differential way in which these inputs engage cortical subpopulations of neurons.
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Affiliation(s)
- Nathaniel C Wright
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - Peter Y Borden
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - Yi Juin Liew
- Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, Atlanta, Georgia 30332 and Beijing University, Beijing China 100871
| | - Michael F Bolus
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - William M Stoy
- Department of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Craig R Forest
- Department of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Garrett B Stanley
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
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16
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Luo Y, Bresee CS, Rudnicki JW, Hartmann MJZ. Constraints on the deformation of the vibrissa within the follicle. PLoS Comput Biol 2021; 17:e1007887. [PMID: 33793548 PMCID: PMC8016108 DOI: 10.1371/journal.pcbi.1007887] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 12/10/2020] [Indexed: 11/26/2022] Open
Abstract
Nearly all mammals have a vibrissal system specialized for tactile sensation, composed of whiskers growing from sensor-rich follicles in the skin. When a whisker deflects against an object, it deforms within the follicle and exerts forces on the mechanoreceptors inside. In addition, during active whisking behavior, muscle contractions around the follicle and increases in blood pressure in the ring sinus will affect the whisker deformation profile. To date, however, it is not yet possible to experimentally measure how the whisker deforms in an intact follicle or its effects on different groups of mechanoreceptors. The present study develops a novel model to predict vibrissal deformation within the follicle sinus complex. The model is based on experimental results from a previous ex vivo study on whisker deformation within the follicle, and on a new histological analysis of follicle tissue. It is then used to simulate whisker deformation within the follicle during passive touch and active whisking. Results suggest that the most likely whisker deformation profile is “S-shaped,” crossing the midline of the follicle right below the ring sinus. Simulations of active whisking indicate that an increase in overall muscle stiffness, an increase in the ratio between deep and superficial intrinsic muscle stiffness, and an increase in sinus blood pressure will all enhance tactile sensitivity. Finally, we discuss how the deformation profiles might map to the responses of primary afferents of each mechanoreceptor type. The mechanical model presented in this study is an important first step in simulating mechanical interactions within whisker follicles. Many mammals rely on whiskers as a mode of tactile sensation, especially when exploring in darkness. Active, rhythmic protraction and retraction of the whiskers, commonly referred to as “whisking,” is observed among many whisker specialist animals. During whisker-based sensing, forces and moments generated by external stimuli are transmitted to the base of the whisker shaft inside the follicle. Within the follicle, the interaction between the whisker’s deformation and the surrounding tissue determines how different groups of mechanoreceptors will deform, thereby transducing the mechanical signals into electrical signals. However, it is not yet possible to experimentally measure this interaction in vivo. We therefore created a mechanical model of the follicle sinus complex to simulate whisker deformation within the follicle resulting from external whisker deflection. Our results provide the first estimate of whisker shape as it deforms in the follicle, during both passive touch and active whisking. In turn, these shape estimates allow us to predict how the whisker will deform against different types of mechanoreceptors at different locations within the follicle. In addition, we find that both intrinsic muscle contraction and an increase in blood pressure will improve the tactile sensitivity of the whisker system.
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Affiliation(s)
- Yifu Luo
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, United States of America
| | - Chris S. Bresee
- Interdepartmental Neuroscience Program, Northwestern University, Evanston, Illinois, United States of America
| | - John W. Rudnicki
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, United States of America
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, United States of America
| | - Mitra J. Z. Hartmann
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, United States of America
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States of America
- * E-mail:
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17
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Laturnus S, Hoffmann A, Chakrabarti S, Schwarz C. Functional analysis of information rates conveyed by rat whisker-related trigeminal nuclei neurons. J Neurophysiol 2021; 125:1517-1531. [PMID: 33689491 DOI: 10.1152/jn.00350.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The rat whisker system connects the tactile environment with the somatosensory thalamocortical system using only two synaptic stages. Encoding properties of the first stage, the primary afferents with somas in the trigeminal ganglion (TG), has been well studied, whereas much less is known from the second stage, the brainstem trigeminal nuclei (TN). The TN are a computational hub giving rise to parallel ascending tactile pathways and receiving feedback from many brain sites. We asked the question, whether encoding properties of TG neurons are kept by two trigeminal nuclei, the principalis (Pr5) and the spinalis interpolaris (Sp5i), respectively giving rise to two "lemniscal" and two "nonlemniscal" pathways. Single units were recorded in anesthetized rats while a single whisker was deflected on a band-limited white noise trajectory. Using information theoretic methods and spike-triggered mixture models (STM), we found that both nuclei encode the stimulus locally in time, i.e., stimulus features more than 10 ms in the past do not significantly influence spike generation. They further encode stimulus kinematics in multiple, distinct response fields, indicating encoding characteristics beyond previously described directional responses. Compared with TG, Pr5 and Sp5i gave rise to lower spike and information rates, but information rate per spike was on par with TG. Importantly, both brainstem nuclei were found to largely keep encoding properties of primary afferents, i.e. local encoding and kinematic response fields. The preservation of encoding properties in channels assumed to serve different functions seems surprising. We discuss the possibility that it might reflect specific constraints of frictional whisker contact with object surfaces.NEW & NOTEWORTHY We studied two trigeminal nuclei containing the second neuron on the tactile pathway of whisker-related tactile information in rats. We found that the subnuclei, traditionally assumed to give rise to functional tactile channels, nevertheless transfer primary afferent information with quite similar properties in terms of integration time and kinematic profile. We discuss whether such commonality may be due the requirement to adapt to physical constraints of frictional whisker contact.
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Affiliation(s)
- Sophie Laturnus
- Systems Neuroscience, Werner Reichardt Center for Integrative Neuroscience, Eberhard Karls University, Tübingen, Germany.,Graduate Training Center for Neuroscience, Eberhard Karls University, Tübingen, Germany
| | - Adrian Hoffmann
- Systems Neuroscience, Werner Reichardt Center for Integrative Neuroscience, Eberhard Karls University, Tübingen, Germany.,Graduate Training Center for Neuroscience, Eberhard Karls University, Tübingen, Germany
| | - Shubhodeep Chakrabarti
- Systems Neuroscience, Werner Reichardt Center for Integrative Neuroscience, Eberhard Karls University, Tübingen, Germany.,Hertie Institute for Clinical Brain Research, Eberhard Karls University, Tübingen, Germany
| | - Cornelius Schwarz
- Systems Neuroscience, Werner Reichardt Center for Integrative Neuroscience, Eberhard Karls University, Tübingen, Germany.,Hertie Institute for Clinical Brain Research, Eberhard Karls University, Tübingen, Germany
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18
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Voigts J, Deister CA, Moore CI. Layer 6 ensembles can selectively regulate the behavioral impact and layer-specific representation of sensory deviants. eLife 2020; 9:48957. [PMID: 33263283 PMCID: PMC7817180 DOI: 10.7554/elife.48957] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 12/01/2020] [Indexed: 11/21/2022] Open
Abstract
Predictive models can enhance the salience of unanticipated input. Here, we tested a key potential node in neocortical model formation in this process, layer (L) 6, using behavioral, electrophysiological and imaging methods in mouse primary somatosensory neocortex. We found that deviant stimuli enhanced tactile detection and were encoded in L2/3 neural tuning. To test the contribution of L6, we applied weak optogenetic drive that changed which L6 neurons were sensory responsive, without affecting overall firing rates in L6 or L2/3. This stimulation selectively suppressed behavioral sensitivity to deviant stimuli, without impacting baseline performance. This stimulation also eliminated deviance encoding in L2/3 but did not impair basic stimulus responses across layers. In contrast, stronger L6 drive inhibited firing and suppressed overall sensory function. These findings indicate that, despite their sparse activity, specific ensembles of stimulus-driven L6 neurons are required to form neocortical predictions, and to realize their behavioral benefit.
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Affiliation(s)
- Jakob Voigts
- Department of Neuroscience and Carney Institute for Brain Science, Brown University, Providence, United States.,Department of Brain and Cognitive Sciences, MIT, Cambridge, United States
| | - Christopher A Deister
- Department of Neuroscience and Carney Institute for Brain Science, Brown University, Providence, United States
| | - Christopher I Moore
- Department of Neuroscience and Carney Institute for Brain Science, Brown University, Providence, United States
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19
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Harrell ER, Goldin MA, Bathellier B, Shulz DE. An elaborate sweep-stick code in rat barrel cortex. SCIENCE ADVANCES 2020; 6:6/38/eabb7189. [PMID: 32938665 PMCID: PMC7494352 DOI: 10.1126/sciadv.abb7189] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
In rat barrel cortex, feature encoding schemes uncovered during broadband whisker stimulation are hard to reconcile with the simple stick-slip code observed during natural tactile behaviors, and this has hindered the development of a generalized computational framework. By designing broadband artificial stimuli to sample the inputs encoded under natural conditions, we resolve this disparity while markedly increasing the percentage of deep layer neurons found to encode whisker movements, as well as the diversity of these encoded features. Deep layer neurons encode two main types of events, sticks and sweeps, corresponding to high angular velocity bumps and large angular displacements with high velocity, respectively. Neurons can exclusively encode sticks or sweeps, or they can encode both, with or without direction selectivity. Beyond unifying coding theories from naturalistic and artificial stimulation studies, these findings delineate a simple and generalizable set of whisker movement features that can support a range of perceptual processes.
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Affiliation(s)
- Evan R Harrell
- Université Paris-Saclay, CNRS, Institut des neurosciences Paris-Saclay (NeuroPSI), Building 32/33, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France.
| | - Matías A Goldin
- Université Paris-Saclay, CNRS, Institut des neurosciences Paris-Saclay (NeuroPSI), Building 32/33, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France
| | - Brice Bathellier
- Université Paris-Saclay, CNRS, Institut des neurosciences Paris-Saclay (NeuroPSI), Building 32/33, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France
| | - Daniel E Shulz
- Université Paris-Saclay, CNRS, Institut des neurosciences Paris-Saclay (NeuroPSI), Building 32/33, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France.
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20
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Staiger JF, Petersen CCH. Neuronal Circuits in Barrel Cortex for Whisker Sensory Perception. Physiol Rev 2020; 101:353-415. [PMID: 32816652 DOI: 10.1152/physrev.00019.2019] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The array of whiskers on the snout provides rodents with tactile sensory information relating to the size, shape and texture of objects in their immediate environment. Rodents can use their whiskers to detect stimuli, distinguish textures, locate objects and navigate. Important aspects of whisker sensation are thought to result from neuronal computations in the whisker somatosensory cortex (wS1). Each whisker is individually represented in the somatotopic map of wS1 by an anatomical unit named a 'barrel' (hence also called barrel cortex). This allows precise investigation of sensory processing in the context of a well-defined map. Here, we first review the signaling pathways from the whiskers to wS1, and then discuss current understanding of the various types of excitatory and inhibitory neurons present within wS1. Different classes of cells can be defined according to anatomical, electrophysiological and molecular features. The synaptic connectivity of neurons within local wS1 microcircuits, as well as their long-range interactions and the impact of neuromodulators, are beginning to be understood. Recent technological progress has allowed cell-type-specific connectivity to be related to cell-type-specific activity during whisker-related behaviors. An important goal for future research is to obtain a causal and mechanistic understanding of how selected aspects of tactile sensory information are processed by specific types of neurons in the synaptically connected neuronal networks of wS1 and signaled to downstream brain areas, thus contributing to sensory-guided decision-making.
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Affiliation(s)
- Jochen F Staiger
- University Medical Center Göttingen, Institute for Neuroanatomy, Göttingen, Germany; and Laboratory of Sensory Processing, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Carl C H Petersen
- University Medical Center Göttingen, Institute for Neuroanatomy, Göttingen, Germany; and Laboratory of Sensory Processing, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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21
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Zweifel NO, Hartmann MJZ. Defining "active sensing" through an analysis of sensing energetics: homeoactive and alloactive sensing. J Neurophysiol 2020; 124:40-48. [PMID: 32432502 DOI: 10.1152/jn.00608.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The term "active sensing" has been defined in multiple ways. Most strictly, the term refers to sensing that uses self-generated energy to sample the environment (e.g., echolocation). More broadly, the definition includes all sensing that occurs when the sensor is moving (e.g., tactile stimuli obtained by an immobile versus moving fingertip) and, broader still, includes all sensing guided by attention or intent (e.g., purposeful eye movements). The present work offers a framework to help disambiguate aspects of the "active sensing" terminology and reveals properties of tactile sensing unique among all modalities. The framework begins with the well-described "sensorimotor loop," which expresses the perceptual process as a cycle involving four subsystems: environment, sensor, nervous system, and actuator. Using system dynamics, we examine how information flows through the loop. This "sensory-energetic loop" reveals two distinct sensing mechanisms that subdivide active sensing into homeoactive and alloactive sensing. In homeoactive sensing, the animal can change the state of the environment, while in alloactive sensing the animal can alter only the sensor's configurational parameters and thus the mapping between input and output. Given these new definitions, examination of the sensory-energetic loop helps identify two unique characteristics of tactile sensing: 1) in tactile systems, alloactive and homeoactive sensing merge to a mutually controlled sensing mechanism, and 2) tactile sensing may require fundamentally different predictions to anticipate reafferent input. We expect this framework may help resolve ambiguities in the active sensing community and form a basis for future theoretical and experimental work regarding alloactive and homeoactive sensing.
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Affiliation(s)
- Nadina O Zweifel
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois
| | - Mitra J Z Hartmann
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois.,Department of Mechanical Engineering, Northwestern University, Evanston, Illinois
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22
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Zhang M, Kwon SE, Ben-Johny M, O'Connor DH, Issa JB. Spectral hallmark of auditory-tactile interactions in the mouse somatosensory cortex. Commun Biol 2020; 3:64. [PMID: 32047263 PMCID: PMC7012892 DOI: 10.1038/s42003-020-0788-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/22/2020] [Indexed: 11/08/2022] Open
Abstract
To synthesize a coherent representation of the external world, the brain must integrate inputs across different types of stimuli. Yet the mechanistic basis of this computation at the level of neuronal populations remains obscure. Here, we investigate tactile-auditory integration using two-photon Ca2+ imaging in the mouse primary (S1) and secondary (S2) somatosensory cortices. Pairing sound with whisker stimulation modulates tactile responses in both S1 and S2, with the most prominent modulation being robust inhibition in S2. The degree of inhibition depends on tactile stimulation frequency, with lower frequency responses the most severely attenuated. Alongside these neurons, we identify sound-selective neurons in S2 whose responses are inhibited by high tactile frequencies. These results are consistent with a hypothesized local mutually-inhibitory S2 circuit that spectrally selects tactile versus auditory inputs. Our findings enrich mechanistic understanding of multisensory integration and suggest a key role for S2 in combining auditory and tactile information.
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Affiliation(s)
- Manning Zhang
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Sung Eun Kwon
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Kavli Neuroscience Discovery Institute, and Brain Science Institute, Baltimore, MD, 21205, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Manu Ben-Johny
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Daniel H O'Connor
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Kavli Neuroscience Discovery Institute, and Brain Science Institute, Baltimore, MD, 21205, USA
| | - John B Issa
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Neurobiology, Northwestern University, Evanston, IL, 60201, USA.
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23
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Ego-Stengel V, Abbasi A, Larroche M, Lassagne H, Boubenec Y, Shulz DE. Mechanical coupling through the skin affects whisker movements and tactile information encoding. J Neurophysiol 2019; 122:1606-1622. [PMID: 31411931 DOI: 10.1152/jn.00863.2018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Rats use their whiskers to extract sensory information from their environment. While exploring, they analyze peripheral stimuli distributed over several whiskers. Previous studies have reported cross-whisker integration of information at several levels of the neuronal pathways from whisker follicles to the somatosensory cortex. In the present study, we investigated the possible coupling between whiskers at a preneuronal level, transmitted by the skin and muscles between follicles. First, we quantified the movement induced on one whisker by deflecting another whisker. Our results show significant mechanical coupling, predominantly when a given whisker's caudal neighbor in the same row is deflected. The magnitude of the effect was correlated with the diameter of the deflected whisker. In addition to changes in whisker angle, we observed curvature changes when the whisker shaft was constrained distally from the base. Second, we found that trigeminal ganglion neurons innervating a given whisker follicle fire action potentials in response to high-magnitude deflections of an adjacent whisker. This functional coupling also shows a bias toward the caudal neighbor located in the same row. Finally, we designed a two-whisker biomechanical model to investigate transmission of forces across follicles. Analysis of the whisker-follicle contact forces suggests that activation of mechanoreceptors in the ring sinus region could account for our electrophysiological results. The model can fully explain the observed caudal bias by the gradient in whisker diameter, with possible contribution of the intrinsic muscles connecting follicles. Overall, our study demonstrates the functional relevance of mechanical coupling on early information processing in the whisker system.NEW & NOTEWORTHY Rodents explore their environment actively by touching objects with their whiskers. A major challenge is to understand how sensory inputs from different whiskers are merged together to form a coherent tactile percept. We demonstrate that external sensory events on one whisker can influence the position of another whisker and, importantly, that they can trigger the activity of mechanoreceptors at its base. This cross-whisker interaction occurs pre-neuronally, through mechanical transmission of forces in the skin.
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Affiliation(s)
- Valerie Ego-Stengel
- Department of Integrative and Computational Neuroscience, Paris-Saclay Institute of Neuroscience (NeuroPSI), UMR9197 CNRS, University Paris-Sud, Gif-sur-Yvette, France
| | - Aamir Abbasi
- Department of Integrative and Computational Neuroscience, Paris-Saclay Institute of Neuroscience (NeuroPSI), UMR9197 CNRS, University Paris-Sud, Gif-sur-Yvette, France
| | - Margot Larroche
- Department of Integrative and Computational Neuroscience, Paris-Saclay Institute of Neuroscience (NeuroPSI), UMR9197 CNRS, University Paris-Sud, Gif-sur-Yvette, France
| | - Henri Lassagne
- Department of Integrative and Computational Neuroscience, Paris-Saclay Institute of Neuroscience (NeuroPSI), UMR9197 CNRS, University Paris-Sud, Gif-sur-Yvette, France
| | - Yves Boubenec
- Department of Integrative and Computational Neuroscience, Paris-Saclay Institute of Neuroscience (NeuroPSI), UMR9197 CNRS, University Paris-Sud, Gif-sur-Yvette, France
| | - Daniel E Shulz
- Department of Integrative and Computational Neuroscience, Paris-Saclay Institute of Neuroscience (NeuroPSI), UMR9197 CNRS, University Paris-Sud, Gif-sur-Yvette, France
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24
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Drew PJ, Winder AT, Zhang Q. Twitches, Blinks, and Fidgets: Important Generators of Ongoing Neural Activity. Neuroscientist 2019; 25:298-313. [PMID: 30311838 PMCID: PMC6800083 DOI: 10.1177/1073858418805427] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Animals and humans continuously engage in small, spontaneous motor actions, such as blinking, whisking, and postural adjustments ("fidgeting"). These movements are accompanied by changes in neural activity in sensory and motor regions of the brain. The frequency of these motions varies in time, is affected by sensory stimuli, arousal levels, and pathology. These fidgeting behaviors can be entrained by sensory stimuli. Fidgeting behaviors will cause distributed, bilateral functional activation in the 0.01 to 0.1 Hz frequency range that will show up in functional magnetic resonance imaging and wide-field calcium neuroimaging studies, and will contribute to the observed functional connectivity among brain regions. However, despite the large potential of these behaviors to drive brain-wide activity, these fidget-like behaviors are rarely monitored. We argue that studies of spontaneous and evoked brain dynamics in awake animals and humans should closely monitor these fidgeting behaviors. Differences in these fidgeting behaviors due to arousal or pathology will "contaminate" ongoing neural activity, and lead to apparent differences in functional connectivity. Monitoring and accounting for the brain-wide activations by these behaviors is essential during experiments to differentiate fidget-driven activity from internally driven neural dynamics.
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Affiliation(s)
- Patrick J Drew
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, USA
- Department of Neurosurgery and Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Aaron T Winder
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, USA
| | - Qingguang Zhang
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, USA
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25
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Abstract
Tactile sensory information from facial whiskers provides nocturnal tunnel-dwelling rodents, including mice and rats, with important spatial and textural information about their immediate surroundings. Whiskers are moved back and forth to scan the environment (whisking), and touch signals from each whisker evoke sparse patterns of neuronal activity in whisker-related primary somatosensory cortex (wS1; barrel cortex). Whisking is accompanied by desynchronized brain states and cell-type-specific changes in spontaneous and evoked neuronal activity. Tactile information, including object texture and location, appears to be computed in wS1 through integration of motor and sensory signals. wS1 also directly controls whisker movements and contributes to learned, whisker-dependent, goal-directed behaviours. The cell-type-specific neuronal circuitry in wS1 that contributes to whisker sensory perception is beginning to be defined.
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State-aware detection of sensory stimuli in the cortex of the awake mouse. PLoS Comput Biol 2019; 15:e1006716. [PMID: 31150385 PMCID: PMC6561583 DOI: 10.1371/journal.pcbi.1006716] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/12/2019] [Accepted: 05/15/2019] [Indexed: 11/19/2022] Open
Abstract
Cortical responses to sensory inputs vary across repeated presentations of identical stimuli, but how this trial-to-trial variability impacts detection of sensory inputs is not fully understood. Using multi-channel local field potential (LFP) recordings in primary somatosensory cortex (S1) of the awake mouse, we optimized a data-driven cortical state classifier to predict single-trial sensory-evoked responses, based on features of the spontaneous, ongoing LFP recorded across cortical layers. Our findings show that, by utilizing an ongoing prediction of the sensory response generated by this state classifier, an ideal observer improves overall detection accuracy and generates robust detection of sensory inputs across various states of ongoing cortical activity in the awake brain, which could have implications for variability in the performance of detection tasks across brain states. Establishing the link between neural activity and behavior is a central goal of neuroscience. One context in which to examine this link is in a sensory detection task, in which an animal is trained to report the presence of a barely perceptible sensory stimulus. In such tasks, both sensory responses in the brain and behavioral responses are highly variable. A simple hypothesis, originating in signal detection theory, is that perceived inputs generate neural activity that cross some threshold for detection. According to this hypothesis, sensory response variability would predict behavioral variability, but previous studies have not born out this prediction. Further complicating the picture, sensory response variability is partially dependent on the ongoing state of cortical activity, and we wondered whether this could resolve the mismatch between response variability and behavioral variability. Here, we use a computational approach to study an adaptive observer that utilizes an ongoing prediction of sensory responsiveness to detect sensory inputs. This observer has higher overall accuracy than the standard ideal observer. Moreover, because of the adaptation, the observer breaks the direct link between neural and behavioral variability, which could resolve discrepancies arising in past studies. We suggest new experiments to test our theory.
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Whisker Vibrations and the Activity of Trigeminal Primary Afferents in Response to Airflow. J Neurosci 2019; 39:5881-5896. [PMID: 31097620 DOI: 10.1523/jneurosci.2971-18.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/18/2019] [Accepted: 04/30/2019] [Indexed: 11/21/2022] Open
Abstract
Rodents are the most commonly studied model system in neuroscience, but surprisingly few studies investigate the natural sensory stimuli that rodent nervous systems evolved to interpret. Even fewer studies examine neural responses to these natural stimuli. Decades of research have investigated the rat vibrissal (whisker) system in the context of direct touch and tactile stimulation, but recent work has shown that rats also use their whiskers to help detect and localize airflow. The present study investigates the neural basis for this ability as dictated by the mechanical response of whiskers to airflow. Mechanical experiments show that a whisker's vibration magnitude depends on airspeed and the intrinsic shape of the whisker. Surprisingly, the direction of the whisker's vibration changes as a function of airflow speed: vibrations transition from parallel to perpendicular with respect to the airflow as airspeed increases. Recordings from primary sensory trigeminal ganglion neurons show that these neurons exhibit responses consistent with those that would be predicted from direct touch. Trigeminal neuron firing rate increases with airspeed, is modulated by the orientation of the whisker relative to the airflow, and is influenced by the whisker's resonant frequencies. We develop a simple model to describe how a population of neurons could leverage mechanical relationships to decode both airspeed and direction. These results open new avenues for studying vibrissotactile regions of the brain in the context of evolutionarily important airflow-sensing behaviors and olfactory search. Although this study used only female rats, all results are expected to generalize to male rats.SIGNIFICANCE STATEMENT The rodent vibrissal (whisker) system has been studied for decades in the context of direct tactile sensation, but recent work has indicated that rats also use whiskers to help localize airflow. Neural circuits in somatosensory regions of the rodent brain thus likely evolved in part to process airflow information. This study investigates the whiskers' mechanical response to airflow and the associated neural response. Airspeed affects the magnitude of whisker vibration and the response magnitude of whisker-sensitive primary sensory neurons in the trigeminal ganglion. Surprisingly, the direction of vibration and the associated directionally dependent neural response changes with airspeed. These findings suggest a population code for airflow speed and direction and open new avenues for studying vibrissotactile regions of the brain.
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Ly C, Shew WL, Barreiro AK. Efficient calculation of heterogeneous non-equilibrium statistics in coupled firing-rate models. JOURNAL OF MATHEMATICAL NEUROSCIENCE 2019; 9:2. [PMID: 31073652 PMCID: PMC6509307 DOI: 10.1186/s13408-019-0070-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/28/2019] [Indexed: 06/09/2023]
Abstract
Understanding nervous system function requires careful study of transient (non-equilibrium) neural response to rapidly changing, noisy input from the outside world. Such neural response results from dynamic interactions among multiple, heterogeneous brain regions. Realistic modeling of these large networks requires enormous computational resources, especially when high-dimensional parameter spaces are considered. By assuming quasi-steady-state activity, one can neglect the complex temporal dynamics; however, in many cases the quasi-steady-state assumption fails. Here, we develop a new reduction method for a general heterogeneous firing-rate model receiving background correlated noisy inputs that accurately handles highly non-equilibrium statistics and interactions of heterogeneous cells. Our method involves solving an efficient set of nonlinear ODEs, rather than time-consuming Monte Carlo simulations or high-dimensional PDEs, and it captures the entire set of first and second order statistics while allowing significant heterogeneity in all model parameters.
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Affiliation(s)
- Cheng Ly
- Department of Statistical Sciences and Operations Research, Virginia Commonwealth University, Richmond, USA
| | - Woodrow L. Shew
- Department of Physics, University of Arkansas, Fayetteville, USA
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Waiblinger C, Wu CM, Bolus MF, Borden PY, Stanley GB. Stimulus Context and Reward Contingency Induce Behavioral Adaptation in a Rodent Tactile Detection Task. J Neurosci 2019; 39:1088-1099. [PMID: 30530858 PMCID: PMC6363924 DOI: 10.1523/jneurosci.2032-18.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 10/30/2018] [Accepted: 11/21/2018] [Indexed: 11/21/2022] Open
Abstract
Behavioral adaptation is a prerequisite for survival in a constantly changing sensory environment, but the underlying strategies and relevant variables driving adaptive behavior are not well understood. Many learning models and neural theories consider probabilistic computations as an efficient way to solve a variety of tasks, especially if uncertainty is involved. Although this suggests a possible role for probabilistic inference and expectation in adaptive behaviors, there is little if any evidence of this relationship experimentally. Here, we investigated adaptive behavior in the rat model by using a well controlled behavioral paradigm within a psychophysical framework to predict and quantify changes in performance of animals trained on a simple whisker-based detection task. The sensory environment of the task was changed by transforming the probabilistic distribution of whisker deflection amplitudes systematically while measuring the animal's detection performance and corresponding rate of accumulated reward. We show that the psychometric function deviates significantly and reversibly depending on the probabilistic distribution of stimuli. This change in performance relates to accumulating a constant reward count across trials, yet it is exempt from changes in reward volume. Our simple model of reward accumulation captures the observed change in psychometric sensitivity and predicts a strategy seeking to maintain reward expectation across trials in the face of the changing stimulus distribution. We conclude that rats are able maintain a constant payoff under changing sensory conditions by flexibly adjusting their behavioral strategy. Our findings suggest the existence of an internal probabilistic model that facilitates behavioral adaptation when sensory demands change.SIGNIFICANCE STATEMENT The strategy animals use to deal with a complex and ever-changing world is a key to understanding natural behavior. This study provides evidence that rodent behavioral performance is highly flexible in the face of a changing stimulus distribution, consistent with a strategy to maintain a desired accumulation of reward.
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Affiliation(s)
- Christian Waiblinger
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - Caroline M Wu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - Michael F Bolus
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - Peter Y Borden
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - Garrett B Stanley
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
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Schriver BJ, Bagdasarov S, Wang Q. Pupil-linked arousal modulates behavior in rats performing a whisker deflection direction discrimination task. J Neurophysiol 2018; 120:1655-1670. [PMID: 29995602 PMCID: PMC6230792 DOI: 10.1152/jn.00290.2018] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/09/2018] [Accepted: 07/09/2018] [Indexed: 11/22/2022] Open
Abstract
Non-luminance-mediated changes in pupil size have been widely used to index arousal state. Recent animal studies have demonstrated correlations between behavioral state-related pupil dynamics and sensory processing. However, the relationship between pupil-linked arousal and behavior in animals performing perceptual tasks has not been fully elucidated. In the present study, we trained head-fixed rats to discriminate between directions of whisker movements using a Go/No-Go discrimination paradigm while imaging their pupils. Reaction times in this discrimination task were significantly slower than in previously reported detection tasks with similar setup, suggesting that discrimination required an increased cognitive load. We found the pupils dilated for all trials following stimulus presentation. Interestingly, in correct rejection trials, where pupil dilations solely resulted from cognitive processing, dilations were larger for more difficult stimuli. Baseline pupil size before stimulus presentation strongly correlated with behavior, as perceptual sensitivity peaked at intermediate pupil baselines and reaction time was fastest at large baselines. We further explored these relationships by investigating to what extent pupil baseline was predictive of upcoming behavior and found that a Bayesian decoder had significantly greater-than-chance probability in correctly predicting behavioral outcomes. Moreover, the outcome of the previous trial showed a strong correlation with behavior on present trials. Animals were more liberal and faster in responding following hit trials, whereas perceptual sensitivity was greatest following correct rejection trials. Taken together, these results suggest a tight correlation between pupil dynamics, perceptual performance, and reaction time in behaving rats, all of which are modulated by fluctuating arousal state. NEW & NOTEWORTHY In this study, we for the first time demonstrated that head-fixed rats were able to discriminate different directions of whisker movement. Interestingly, we found that the pupil dilated more when discriminating more difficult stimuli, a phenomenon reported in human subjects but not in animals. Baseline pupil size before stimulus presentation was found to strongly correlate with behavior, and a Bayesian decoder had significantly greater-than-chance probability in correctly predicting behavioral outcomes based on the baseline pupil size.
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Affiliation(s)
- Brian J Schriver
- Department of Biomedical Engineering, Columbia University , New York, New York
| | - Svetlana Bagdasarov
- Department of Biomedical Engineering, Columbia University , New York, New York
| | - Qi Wang
- Department of Biomedical Engineering, Columbia University , New York, New York
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31
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Cortical modulation of sensory flow during active touch in the rat whisker system. Nat Commun 2018; 9:3907. [PMID: 30254195 PMCID: PMC6156333 DOI: 10.1038/s41467-018-06200-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 08/22/2018] [Indexed: 02/01/2023] Open
Abstract
Sensory gating, where responses to stimuli during sensor motion are reduced in amplitude, is a hallmark of active sensing systems. In the rodent whisker system, sensory gating has been described only at the thalamic and cortical stages of sensory processing. However, does sensory gating originate at an even earlier synaptic level? Most importantly, is sensory gating under top-down or bottom-up control? To address these questions, we used an active touch task in behaving rodents while recording from the trigeminal sensory nuclei. First, we show that sensory gating occurs in the brainstem at the first synaptic level. Second, we demonstrate that sensory gating is pathway-specific, present in the lemniscal but not in the extralemniscal stream. Third, using cortical lesions resulting in the complete abolition of sensory gating, we demonstrate its cortical dependence. Fourth, we show accompanying decreases in whisking-related activity, which could be the putative gating signal. During active touch, sensory responses to object touch are gated at the level of thalamus and cortex. Here, the authors report gating at the level of the brainstem and show that an intact somatosensory cortex is essential for this response modulation.
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32
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Oladazimi M, Brendel W, Schwarz C. Biomechanical Texture Coding in Rat Whiskers. Sci Rep 2018; 8:11139. [PMID: 30042423 PMCID: PMC6057990 DOI: 10.1038/s41598-018-29225-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/09/2018] [Indexed: 11/30/2022] Open
Abstract
Classically, texture discrimination has been thought to be based on ‘global’ codes, i.e. frequency (signal analysis based on Fourier analysis) or intensity (signal analysis based on averaging), which both rely on integration of the vibrotactile signal across time and/or space. Recently, a novel ‘local’ coding scheme based on the waveform of frictional movements, discrete short lasting kinematic events (i.e. stick-slip movements called slips) has been formulated. We performed biomechanical measurements of relative movements of a rat vibrissa across sandpapers of different roughness. We find that the classic global codes convey some information about texture identity, but are consistently outperformed by the slip-based local code. Moreover, the slip code also surpasses the global ones in coding for active scanning parameters. This is remarkable as it suggests that the slip code would explicitly allow the whisking rat to optimize perception by selecting goal-specific scanning strategies.
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Affiliation(s)
- Maysam Oladazimi
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University of Tübingen, Tübingen, Germany.,Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Wieland Brendel
- Computational Neuroscience, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Cornelius Schwarz
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University of Tübingen, Tübingen, Germany. .,Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany.
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Waiblinger C, Whitmire CJ, Sederberg A, Stanley GB, Schwarz C. Primary Tactile Thalamus Spiking Reflects Cognitive Signals. J Neurosci 2018; 38:4870-4885. [PMID: 29703788 PMCID: PMC6596129 DOI: 10.1523/jneurosci.2403-17.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 03/30/2018] [Accepted: 04/08/2018] [Indexed: 11/21/2022] Open
Abstract
Little is known about whether information transfer at primary sensory thalamic nuclei is modified by behavioral context. Here we studied the influence of previous decisions/rewards on current choices and preceding spike responses of ventroposterior medial thalamus (VPm; the primary sensory thalamus in the rat whisker-related tactile system). We trained head-fixed rats to detect a ramp-like deflection of one whisker interspersed within ongoing white noise stimulation. Using generative modeling of behavior, we identify two task-related variables that are predictive of actual decisions. The first reflects task engagement on a local scale ("trial history": defined as the decisions and outcomes of a small number of past trials), whereas the other captures behavioral dynamics on a global scale ("satiation": slow dynamics of the response pattern along an entire session). Although satiation brought about a slow drift from Go to NoGo decisions during the session, trial history was related to local (trial-by-trial) patterning of Go and NoGo decisions. A second model that related the same predictors first to VPm spike responses, and from there to decisions, indicated that spiking, in contrast to behavior, is sensitive to trial history but relatively insensitive to satiation. Trial history influences VPm spike rates and regularity such that a history of Go decisions would predict fewer noise-driven spikes (but more regular ones), and more ramp-driven spikes. Neuronal activity in VPm, thus, is sensitive to local behavioral history, and may play an important role in higher-order cognitive signaling.SIGNIFICANCE STATEMENT It is an important question for perceptual and brain functions to find out whether cognitive signals modulate the sensory signal stream and if so, where in the brain this happens. This study provides evidence that decision and reward history can already be reflected in the ascending sensory pathway, on the level of first-order sensory thalamus. Cognitive signals are relayed very selectively such that only local trial history (spanning a few trials) but not global history (spanning an entire session) are reflected.
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Affiliation(s)
- Christian Waiblinger
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience
- Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany, and
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - Clarissa J Whitmire
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - Audrey Sederberg
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - Garrett B Stanley
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332
| | - Cornelius Schwarz
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience,
- Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany, and
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Allitt BJ, Johnstone VPA, Richards KL, Yan EB, Rajan R. Progesterone Sharpens Temporal Response Profiles of Sensory Cortical Neurons in Animals Exposed to Traumatic Brain Injury. Cell Transplant 2018; 26:1202-1223. [PMID: 28933224 PMCID: PMC5657734 DOI: 10.1177/0963689717714326] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Traumatic brain injury (TBI) initiates a cascade of pathophysiological changes that are both complex and difficult to treat. Progesterone (P4) is a neuroprotective treatment option that has shown excellent preclinical benefits in the treatment of TBI, but these benefits have not translated well in the clinic. We have previously shown that P4 exacerbates the already hypoactive upper cortical responses in the short-term post-TBI and does not reduce upper cortical hyperactivity in the long term, and we concluded that there is no tangible benefit to sensory cortex firing strength. Here we examined the effects of P4 treatment on temporal coding resolution in the rodent sensory cortex in both the short term (4 d) and long term (8 wk) following impact-acceleration–induced TBI. We show that in the short-term postinjury, TBI has no effect on sensory cortex temporal resolution and that P4 also sharpens the response profile in all cortical layers in the uninjured brain and all layers other than layer 2 (L2) in the injured brain. In the long term, TBI broadens the response profile in all cortical layers despite firing rate hyperactivity being localized to upper cortical layers and P4 sharpens the response profile in TBI animals in all layers other than L2 and has no long-term effect in the sham brain. These results indicate that P4 has long-term effects on sensory coding that may translate to beneficial perceptual outcomes. The effects seen here, combined with previous beneficial preclinical data, emphasize that P4 is still a potential treatment option in ameliorating TBI-induced disorders.
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Affiliation(s)
- Benjamin J Allitt
- 1 Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Victoria P A Johnstone
- 1 Department of Physiology, Monash University, Clayton, Victoria, Australia.,2 School of Anatomy, Physiology and Human Biology, The University of Western Australia, Perth, Western Australia, Australia
| | - Katrina L Richards
- 1 Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Edwin B Yan
- 1 Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Ramesh Rajan
- 1 Department of Physiology, Monash University, Clayton, Victoria, Australia
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35
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Seale M, Cummins C, Viola IM, Mastropaolo E, Nakayama N. Design principles of hair-like structures as biological machines. J R Soc Interface 2018; 15:20180206. [PMID: 29848593 PMCID: PMC6000178 DOI: 10.1098/rsif.2018.0206] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/08/2018] [Indexed: 12/02/2022] Open
Abstract
Hair-like structures are prevalent throughout biology and frequently act to sense or alter interactions with an organism's environment. The overall shape of a hair is simple: a long, filamentous object that protrudes from the surface of an organism. This basic design, however, can confer a wide range of functions, owing largely to the flexibility and large surface area that it usually possesses. From this simple structural basis, small changes in geometry, such as diameter, curvature and inter-hair spacing, can have considerable effects on mechanical properties, allowing functions such as mechanosensing, attachment, movement and protection. Here, we explore how passive features of hair-like structures, both individually and within arrays, enable diverse functions across biology. Understanding the relationships between form and function can provide biologists with an appreciation for the constraints and possibilities on hair-like structures. Additionally, such structures have already been used in biomimetic engineering with applications in sensing, water capture and adhesion. By examining hairs as a functional mechanical unit, geometry and arrangement can be rationally designed to generate new engineering devices and ideas.
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Affiliation(s)
- Madeleine Seale
- School of Biological Sciences, Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, UK
- School of Engineering, Institute for Integrated Micro and Nano Systems, University of Edinburgh, Edinburgh, UK
- SynthSys Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
| | - Cathal Cummins
- School of Biological Sciences, Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, UK
- SynthSys Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
- School of Engineering, Institute for Energy Systems, University of Edinburgh, Edinburgh, UK
| | - Ignazio Maria Viola
- School of Engineering, Institute for Energy Systems, University of Edinburgh, Edinburgh, UK
| | - Enrico Mastropaolo
- School of Engineering, Institute for Integrated Micro and Nano Systems, University of Edinburgh, Edinburgh, UK
| | - Naomi Nakayama
- School of Biological Sciences, Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, UK
- SynthSys Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
- Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh, UK
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36
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Isett BR, Feasel SH, Lane MA, Feldman DE. Slip-Based Coding of Local Shape and Texture in Mouse S1. Neuron 2018; 97:418-433.e5. [PMID: 29307709 PMCID: PMC5773356 DOI: 10.1016/j.neuron.2017.12.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 10/23/2017] [Accepted: 12/14/2017] [Indexed: 01/13/2023]
Abstract
Tactile objects have both local geometry (shape) and broader macroscopic texture, but how these different spatial scales are simultaneously encoded during active touch is unknown. In the whisker system, we tested for a shared code based on localized whisker micromotions (stick-slips) and slip-evoked spikes. We trained mice to discriminate smooth from rough surfaces, including ridged gratings and sandpaper. Whisker slips locked to ridges and evoked temporally precise spikes (<10 ms jitter) in somatosensory cortex (S1) that could resolve ridges with ∼1 mm accuracy. Slip-sensitive neurons also encoded touch and texture. On rough surfaces, both slip-evoked spikes and an additional non-slip signal elevated mean firing rate, allowing accurate rough-smooth texture decoding from population firing rate. Eighteen percent of neurons were selective among rough surfaces. Thus, slips elicit spatially and temporally precise spiking in S1 that simultaneously encodes local shape (ridges) and is integrated into a macroscopic firing rate code for roughness.
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Affiliation(s)
- Brian R Isett
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Sierra H Feasel
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Monet A Lane
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Daniel E Feldman
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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37
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Bessaih T, Higley MJ, Contreras D. Millisecond precision temporal encoding of stimulus features during cortically generated gamma oscillations in the rat somatosensory cortex. J Physiol 2018; 596:515-534. [PMID: 29265375 DOI: 10.1113/jp275245] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 12/13/2017] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS Rodents explore their immediate environment using their whiskers. Such exploration leads to micromotions, which contain many high-frequency (50-200 Hz) components. High-frequency whisker motion is represented faithfully in the temporal structure of the spike trains of trigeminal neurons. However, the representation of high-frequency sensory inputs in cortex is not fully understood. By combining extracellular and intracellular recordings in the rat somatosensory cortex and thalamus, we show that high-frequency sensory inputs, either sinusoidal or white noise, elicit internally generated gamma (20-60 Hz) band oscillations in cortical networks. Gamma oscillations modulate cortical spike probability while preserving sub-millisecond phase relations with high-frequency sensory inputs. Consequently, our results indicate that millisecond precision stimulus-locked spiking activity and sensory-induced gamma oscillation can constitute independent multiplexed coding schemes at the single-cell level. ABSTRACT In the natural environment, tactile exploration often leads to high-frequency vibrations at the level of the sensory organs. Single-unit recordings of cortical neurons have pointed towards either a rate or a temporal code for representing high-frequency tactile signals. In cortical networks, sensory processing results from the interaction between feedforward inputs relayed from the thalamus and internally generated activity. However, how the emergent activity represents high-frequency sensory input is not fully understood. Using multisite single-unit, local field potential and intracellular recordings in the somatosensory cortex and thalamus of lightly sedated male rats, we measured neuronal responses evoked by sinusoidal and band-pass white noise whisker stimulation at frequencies that encompass those observed during texture exploration (50-200 Hz). We found that high-frequency sensory inputs relayed from the thalamus elicit both sub-millisecond stimulus-locked responses and internally generated gamma (20-60 Hz) band oscillations in cortical networks. Gamma oscillations modulate spike probability while preserving sub-millisecond phase relations with sensory inputs. Therefore, precise stimulus-locked spiking activity and sensory-induced gamma oscillations can constitute independent multiplexed coding schemes at the single-cell level.
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Affiliation(s)
- Thomas Bessaih
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), 75005, Paris, France.,Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Michael J Higley
- Department of Neuroscience, Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT, 06520, USA.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale School of Medicine, New Haven, CT, 06520, USA.,Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Diego Contreras
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
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38
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Barrel Cortex: What is it Good for? Neuroscience 2018; 368:3-16. [DOI: 10.1016/j.neuroscience.2017.05.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 12/21/2022]
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Allitt BJ, Alwis DS, Rajan R. Laminar-specific encoding of texture elements in rat barrel cortex. J Physiol 2017; 595:7223-7247. [PMID: 28929510 PMCID: PMC5709323 DOI: 10.1113/jp274865] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 09/06/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS For rats texture discrimination is signalled by the large face whiskers by stick-slip events. Neural encoding of repetitive stick-slip events will be influenced by intrinsic properties of adaptation. We show that texture coding in the barrel cortex is laminar specific and follows a power function. Our results also show layer 2 codes for novel feature elements via robust firing rates and temporal fidelity. We conclude that texture coding relies on a subtle neural ensemble to provide important object information. ABSTRACT Texture discrimination by rats is exquisitely guided by fine-grain mechanical stick-slip motions of the face whiskers as they encounter, stick to and slip past successive texture-defining surface features such as bumps and grooves. Neural encoding of successive stick-slip texture events will be shaped by adaptation, common to all sensory systems, whereby receptor and neural responses to a stimulus are affected by responses to preceding stimuli, allowing resetting to signal novel information. Additionally, when a whisker is actively moved to contact and brush over surfaces, that motion itself generates neural responses that could cause adaptation of responses to subsequent stick-slip events. Nothing is known about encoding in the rat whisker system of stick-slip events defining textures of different grain or the influence of adaptation from whisker protraction or successive texture-defining stick-slip events. Here we recorded responses from halothane-anaesthetized rats in response to texture-defining stimuli applied to passive whiskers. We demonstrate that: across the columnar network of the whisker-recipient barrel cortex, adaptation in response to repetitive stick-slip events is strongest in uppermost layers and equally lower thereafter; neither whisker protraction speed nor stick-slip frequency impede encoding of stick-slip events at rates up to 34.08 Hz; and layer 2 normalizes responses to whisker protraction to resist effects on texture signalling. Thus, within laminar-specific response patterns, barrel cortex reliably encodes texture-defining elements even to high frequencies.
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Affiliation(s)
| | - Dasuni S. Alwis
- Department of PhysiologyMonash UniversityClaytonVIC3800Australia
| | - Ramesh Rajan
- Department of PhysiologyMonash UniversityClaytonVIC3800Australia
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Bale MR, Maravall M. Organization of sensory feature selectivity in the whisker system. Neuroscience 2017; 368:70-80. [PMID: 28918260 PMCID: PMC5798594 DOI: 10.1016/j.neuroscience.2017.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/25/2017] [Accepted: 09/05/2017] [Indexed: 12/14/2022]
Abstract
Neurons in the whisker system are selective to spatial and dynamical properties – features – of sensory stimuli. At each stage of the pathway, different neurons encode distinct features, generating a rich population representation. Whisker touch is robustly represented; neurons respond to touch-driven fast fluctuations in forces at the whisker base. Cortical neurons have more complex and context-dependent selectivity than subcortical, e.g., to collective whisker motion. Understanding how these signals are integrated to construct whisker-mediated percepts requires further research.
Our sensory receptors are faced with an onslaught of different environmental inputs. Each sensory event or encounter with an object involves a distinct combination of physical energy sources impinging upon receptors. In the rodent whisker system, each primary afferent neuron located in the trigeminal ganglion innervates and responds to a single whisker and encodes a distinct set of physical stimulus properties – features – corresponding to changes in whisker angle and shape and the consequent forces acting on the whisker follicle. Here we review the nature of the features encoded by successive stages of processing along the whisker pathway. At each stage different neurons respond to distinct features, such that the population as a whole represents diverse properties. Different neuronal types also have distinct feature selectivity. Thus, neurons at the same stage of processing and responding to the same whisker nevertheless play different roles in representing objects contacted by the whisker. This diversity, combined with the precise timing and high reliability of responses, enables populations at each stage to represent a wide range of stimuli. Cortical neurons respond to more complex stimulus properties – such as correlated motion across whiskers – than those at early subcortical stages. Temporal integration along the pathway is comparatively weak: neurons up to barrel cortex (BC) are sensitive mainly to fast (tens of milliseconds) fluctuations in whisker motion. The topographic organization of whisker sensitivity is paralleled by systematic organization of neuronal selectivity to certain other physical features, but selectivity to touch and to dynamic stimulus properties is distributed in “salt-and-pepper” fashion.
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Affiliation(s)
- Michael R Bale
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Miguel Maravall
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
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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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Estebanez L, Férézou I, Ego-Stengel V, Shulz DE. Representation of tactile scenes in the rodent barrel cortex. Neuroscience 2017; 368:81-94. [PMID: 28843997 DOI: 10.1016/j.neuroscience.2017.08.039] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/17/2017] [Accepted: 08/21/2017] [Indexed: 11/29/2022]
Abstract
After half a century of research, the sensory features coded by neurons of the rodent barrel cortex remain poorly understood. Still, views of the sensory representation of whisker information are increasingly shifting from a labeled line representation of single-whisker deflections to a selectivity for specific elements of the complex statistics of the multi-whisker deflection patterns that take place during spontaneous rodent behavior - so called natural tactile scenes. Here we review the current knowledge regarding the coding of patterns of whisker stimuli by barrel cortex neurons, from responses to single-whisker deflections to the representation of complex tactile scenes. A number of multi-whisker tunings have already been identified, including center-surround feature extraction, angular tuning during edge-like multi-whisker deflections, and even tuning to specific statistical properties of the tactile scene such as the level of correlation across whiskers. However, a more general model of the representation of multi-whisker information in the barrel cortex is still missing. This is in part because of the lack of a human intuition regarding the perception emerging from a whisker system, but also because in contrast to other primary sensory cortices such as the visual cortex, the spatial feature selectivity of barrel cortex neurons rests on highly nonlinear interactions that remained hidden to classical receptive field approaches.
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Affiliation(s)
- Luc Estebanez
- Unité de Neuroscience, Information et Complexité (UNIC), Centre National de la Recherche Scientifique, FRE 3693, 91198 Gif-sur-Yvette, France
| | - Isabelle Férézou
- Unité de Neuroscience, Information et Complexité (UNIC), Centre National de la Recherche Scientifique, FRE 3693, 91198 Gif-sur-Yvette, France
| | - Valérie Ego-Stengel
- Unité de Neuroscience, Information et Complexité (UNIC), Centre National de la Recherche Scientifique, FRE 3693, 91198 Gif-sur-Yvette, France
| | - Daniel E Shulz
- Unité de Neuroscience, Information et Complexité (UNIC), Centre National de la Recherche Scientifique, FRE 3693, 91198 Gif-sur-Yvette, France.
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Bilateral Discrimination of Tactile Patterns without Whisking in Freely Running Rats. J Neurosci 2017; 37:7567-7579. [PMID: 28663200 DOI: 10.1523/jneurosci.0528-17.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/22/2017] [Accepted: 06/17/2017] [Indexed: 11/21/2022] Open
Abstract
A majority of whisker discrimination tasks in rodents are performed on head-fixed animals to facilitate tracking or control of the sensory inputs. However, head fixation critically restrains the behavior and thus the incoming stimuli compared with those occurring in natural conditions. In this study, we investigated whether freely behaving rats can discriminate fine tactile patterns while running, in particular when stimuli are presented simultaneously on both sides of the snout. We developed a two-alternative forced-choice task in an automated modified T-maze. Stimuli were either a surface with no bars (smooth) or with vertical bars spaced irregularly or regularly. While running at full speed, rats encountered simultaneously the two discriminanda placed on the two sides of the central aisle. Rats learned to recognize regular bars versus a smooth surface in 8 weeks. They solved the task while running at an average speed of 1 m/s, so that the contact with the stimulus lasted <1 typical whisking cycle, precluding the use of active whisking. Whisker-tracking analysis revealed an asymmetry in the position of the whiskers: they oriented toward the rewarded stimulus during successful trials as early as 60 ms after the first possible contact. We showed that the whiskers and activity in the primary somatosensory cortex are involved during the discrimination process. Finally, we identified irregular patterns of bars that the rats can discriminate from the regular one. This novel task shows that freely moving rodents can make simultaneous bilateral tactile discrimination without whisking.SIGNIFICANCE STATEMENT The whisker system of rodents is a widely used model to study tactile processing. Rats show remarkable abilities in discriminating surfaces by actively moving their whiskers (whisking) against stimuli, typically sampling them several times. This motor strategy affects considerably the way that tactile information is acquired and thus the way that neuronal networks process the information. However, when rats run at high speed, they protract their whiskers in front of the snout without large movements. Here, we investigated whether rats are able to discriminate regular and irregular patterns of vertical bars while running without whisking. We found that the animals can perform a bilateral simultaneous discrimination without whisking and that this involves both whiskers and barrel cortex activity.
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Carvell GE, Simons DJ. Effect of whisker geometry on contact force produced by vibrissae moving at different velocities. J Neurophysiol 2017; 118:1637-1649. [PMID: 28659457 DOI: 10.1152/jn.00046.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 11/22/2022] Open
Abstract
Rats and mice are able to perform a variety of subtle tactile discriminations with their mystacial vibrissae. Increasingly, the design and interpretation of neurophysiological and behavioral studies are inspired by and linked to a more precise understanding of the detailed physical properties of the whiskers and their associated hair follicles. Here we used a piezoelectric sensor (bimorph) to examine how contact forces are influenced by the geometry of individual whisker hairs. For a given point along a whisker, bimorph signals are linearly related to whisker movement velocity. The slope of this linear function, called velocity sensitivity (VS), diminishes nonlinearly as whisker diameter decreases. Whiskers differ in overall length, thickness, and proximal-distal taper. Thus VS varies along an individual whisker and among different whiskers on the mystacial pad. Thinner, shorter whiskers, such as those located rostrally in rats and those in mice, have lower overall VSs, rendering them potentially less effective for mediating discriminations that rely on subtle velocity cues. The nonlinear effect of diameter combined with the linear effect of arc length produces radial distance tuning curves wherein small differences in the proximal-distal location of impacts yields larger differences in signal magnitude. Such position-dependent cues could contribute to the localization of objects near the face. Proximal-to-distal changes in contact location during whisking sweeps could also provide signals that aid texture discrimination.NEW & NOTEWORTHY This study describes the geometry of facial whiskers distributed across the mystacial pad with emphasis on velocity encoding of object strikes. Findings indicate how the shapes, lengths, and thicknesses of individual hairs can contribute to sophisticated vibrissa-based tactile discrimination.
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Affiliation(s)
- George E Carvell
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania; and.,Department of Neurobiology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Daniel J Simons
- Department of Neurobiology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
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Rigosa J, Lucantonio A, Noselli G, Fassihi A, Zorzin E, Manzino F, Pulecchi F, Diamond ME. Dye-enhanced visualization of rat whiskers for behavioral studies. eLife 2017; 6:e25290. [PMID: 28613155 PMCID: PMC5511012 DOI: 10.7554/elife.25290] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 06/13/2017] [Indexed: 11/13/2022] Open
Abstract
Visualization and tracking of the facial whiskers is required in an increasing number of rodent studies. Although many approaches have been employed, only high-speed videography has proven adequate for measuring whisker motion and deformation during interaction with an object. However, whisker visualization and tracking is challenging for multiple reasons, primary among them the low contrast of the whisker against its background. Here, we demonstrate a fluorescent dye method suitable for visualization of one or more rat whiskers. The process makes the dyed whisker(s) easily visible against a dark background. The coloring does not influence the behavioral performance of rats trained on a vibrissal vibrotactile discrimination task, nor does it affect the whiskers' mechanical properties.
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Affiliation(s)
- Jacopo Rigosa
- International School for Advanced Studies, Trieste, Italy
| | | | | | - Arash Fassihi
- International School for Advanced Studies, Trieste, Italy
| | - Erik Zorzin
- International School for Advanced Studies, Trieste, Italy
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Matched Behavioral and Neural Adaptations for Low Sound Level Echolocation in a Gleaning Bat, Antrozous pallidus. eNeuro 2017; 4:eN-NWR-0018-17. [PMID: 28275715 PMCID: PMC5334453 DOI: 10.1523/eneuro.0018-17.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 11/21/2022] Open
Abstract
In active sensing, animals make motor adjustments to match sensory inputs to specialized neural circuitry. Here, we describe an active sensing system for sound level processing. The pallid bat uses downward frequency-modulated (FM) sweeps as echolocation calls for general orientation and obstacle avoidance. The bat's auditory cortex contains a region selective for these FM sweeps (FM sweep-selective region, FMSR). We show that the vast majority of FMSR neurons are sensitive and strongly selective for relatively low levels (30-60 dB SPL). Behavioral testing shows that when a flying bat approaches a target, it reduces output call levels to keep echo levels between ∼30 and 55 dB SPL. Thus, the pallid bat behaviorally matches echo levels to an optimized neural representation of sound levels. FMSR neurons are more selective for sound levels of FM sweeps than tones, suggesting that across-frequency integration enhances level tuning. Level-dependent timing of high-frequency sideband inhibition in the receptive field shapes increased level selectivity for FM sweeps. Together with previous studies, these data indicate that the same receptive field properties shape multiple filters (sweep direction, rate, and level) for FM sweeps, a sound common in multiple vocalizations, including human speech. The matched behavioral and neural adaptations for low-intensity echolocation in the pallid bat will facilitate foraging with reduced probability of acoustic detection by prey.
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Treadmill exercise suppressed stress-induced dendritic spine elimination in mouse barrel cortex and improved working memory via BDNF/TrkB pathway. Transl Psychiatry 2017; 7:e1069. [PMID: 28323283 PMCID: PMC5416682 DOI: 10.1038/tp.2017.41] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 01/18/2017] [Indexed: 12/15/2022] Open
Abstract
Stress-related memory deficit is correlated with dendritic spine loss. Physical exercise improves memory function and promotes spinogenesis. However, no studies have been performed to directly observe exercise-related effects on spine dynamics, in association with memory function. This study utilized transcranial two-photon in vivo microscopy to investigate dendritic spine formation and elimination in barrel cortex of mice under physical constrain or naive conditions, followed by memory performance in a whisker-dependent novel texture discrimination task. We found that stressed mice had elevated spine elimination rate in mouse barrel cortex plus deficits in memory retrieval, both of which can be rescued by chronic exercise on treadmill. Exercise also elevated brain-derived neurotrophic factor (BDNF) expression in barrel cortex. The above-mentioned rescuing effects for both spinognesis and memory function were abolished after inhibiting BDNF/tyrosine kinase B (TrkB) pathway. In summary, this study demonstrated the improvement of stress-associated memory function by exercise via facilitating spine retention in a BDNF/TrkB-dependent manner.
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Pixying Behavior: A Versatile Real-Time and Post Hoc Automated Optical Tracking Method for Freely Moving and Head Fixed Animals. eNeuro 2017; 4:eN-MNT-0245-16. [PMID: 28275712 PMCID: PMC5318546 DOI: 10.1523/eneuro.0245-16.2017] [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: 08/17/2016] [Revised: 12/31/2016] [Accepted: 01/10/2017] [Indexed: 11/21/2022] Open
Abstract
Here, we describe an automated optical method for tracking animal behavior in both head-fixed and freely moving animals, in real time and offline. It takes advantage of an off-the-shelf camera system, the Pixy camera, designed as a fast vision sensor for robotics that uses a color-based filtering algorithm at 50 Hz to track objects. Using customized software, we demonstrate the versatility of our approach by first tracking the rostro-caudal motion of individual adjacent row (D1, D2) or arc whiskers (β, γ), or a single whisker and points on the whisker pad, in head-fixed mice performing a tactile task. Next, we acquired high-speed video and Pixy data simultaneously and applied the pixy-based real-time tracking to high-speed video data. With this approach, we expand the temporal resolution of the Pixy camera and track motion (post hoc) at the limit of high-speed video frame rates. Finally, we show that this system is flexible: it can be used to track individual whisker or limb position without any sophisticated object tracking algorithm, it can be used in many lighting conditions including infrared (IR); it can be used to track head rotation and location of multiple animals simultaneously. Our system makes behavioral monitoring possible in virtually any biological setting.
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Claverie LN, Boubenec Y, Debrégeas G, Prevost AM, Wandersman E. Whisker Contact Detection of Rodents Based on Slow and Fast Mechanical Inputs. Front Behav Neurosci 2017; 10:251. [PMID: 28119582 PMCID: PMC5222834 DOI: 10.3389/fnbeh.2016.00251] [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: 10/11/2016] [Accepted: 12/23/2016] [Indexed: 11/13/2022] Open
Abstract
Rodents use their whiskers to locate nearby objects with an extreme precision. To perform such tasks, they need to detect whisker/object contacts with a high temporal accuracy. This contact detection is conveyed by classes of mechanoreceptors whose neural activity is sensitive to either slow or fast time varying mechanical stresses acting at the base of the whiskers. We developed a biomimetic approach to separate and characterize slow quasi-static and fast vibrational stress signals acting on a whisker base in realistic exploratory phases, using experiments on both real and artificial whiskers. Both slow and fast mechanical inputs are successfully captured using a mechanical model of the whisker. We present and discuss consequences of the whisking process in purely mechanical terms and hypothesize that free whisking in air sets a mechanical threshold for contact detection. The time resolution and robustness of the contact detection strategies based on either slow or fast stress signals are determined. Contact detection based on the vibrational signal is faster and more robust to exploratory conditions than the slow quasi-static component, although both slow/fast components allow localizing the object.
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Affiliation(s)
- Laure N Claverie
- Sorbonne Universités, UPMC Univ Paris 06, UMR 8237, Laboratoire Jean Perrin Paris, France
| | - Yves Boubenec
- Laboratoire des Systèmes Perceptifs, Département d'études Cognitives, ENS, PSL Research University, Centre National de la Recherche Scientifique Paris, France
| | - Georges Debrégeas
- Sorbonne Universités, UPMC Univ Paris 06, UMR 8237, Laboratoire Jean Perrin Paris, France
| | - Alexis M Prevost
- Sorbonne Universités, UPMC Univ Paris 06, UMR 8237, Laboratoire Jean Perrin Paris, France
| | - Elie Wandersman
- Sorbonne Universités, UPMC Univ Paris 06, UMR 8237, Laboratoire Jean Perrin Paris, France
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Ranjbar-Slamloo Y, Arabzadeh E. High-velocity stimulation evokes "dense" population response in layer 2/3 vibrissal cortex. J Neurophysiol 2016; 117:1218-1228. [PMID: 28003414 DOI: 10.1152/jn.00815.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/14/2016] [Accepted: 12/14/2016] [Indexed: 12/23/2022] Open
Abstract
Supragranular layers of sensory cortex are known to exhibit sparse firing. In rodent vibrissal cortex, a small fraction of neurons in layer 2 and 3 (L2/3) respond to whisker stimulation. In this study, we combined whole cell recording and two-photon imaging in anesthetized mice and quantified the synaptic response and spiking profile of L2/3 neurons. Previous literature has shown that neurons across layers of vibrissal cortex are tuned to the velocity of whisker movement. We therefore used a broad range of stimuli that included the standard range of velocities (0-1.2 deg/ms) and extended to a "sharp" high-velocity deflection (3.8 deg/ms). Consistent with previous literature, whole cell recording revealed a sparse response to the standard range of velocities: although all recorded cells showed tuning to velocity in their postsynaptic potentials, only a small fraction produced stimulus-evoked spikes. In contrast, the sharp stimulus evoked reliable spiking in the majority of neurons. The action potential threshold of spikes evoked by the sharp stimulus was significantly lower than that of the spontaneous spikes. Juxtacellular recordings confirmed that application of sharp stimulus to single or multiple whiskers produced temporally precise spiking with minimal trial-to-trial spike count variability (Fano factors equal or close to the theoretical minimum). Two-photon imaging further confirmed that most neurons that were not responsive to the standard deflections responded to the sharp stimulus. Altogether, our results indicate that sparseness in L2/3 cortex depends on the choice of stimulus: strong single- or multiwhisker stimulation can induce the transition from sparse to "dense" population response.NEW & NOTEWORTHY In superficial layers of sensory cortex, only a small fraction of neurons fire most of the spontaneous and sensory evoked spikes. However, the functional relevance of such "sparse" activity remains unknown. We found that a "dense" population response is evoked by high-velocity micromotions applied to whiskers. Our results suggest that flashes of precisely timed population response on an almost silent background can provide a high capacity for coding of ecologically salient stimuli.
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Affiliation(s)
- Yadollah Ranjbar-Slamloo
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT 0200, Australia; and.,Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, Australia
| | - Ehsan Arabzadeh
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT 0200, Australia; and .,Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, Australia
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