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Upadhyay A, Gradwell MA, Vajtay TJ, Conner J, Sanyal AA, Azadegan C, Patel KR, Thackray JK, Bohic M, Imai F, Ogundare SO, Yoshida Y, Abdus-Saboor I, Azim E, Abraira VE. The dorsal column nuclei scale mechanical sensitivity in naive and neuropathic pain states. Cell Rep 2025; 44:115556. [PMID: 40202848 PMCID: PMC12093272 DOI: 10.1016/j.celrep.2025.115556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 12/18/2024] [Accepted: 03/21/2025] [Indexed: 04/11/2025] Open
Abstract
During pathological conditions, tactile stimuli can aberrantly engage nociceptive pathways leading to the perception of touch as pain, known as mechanical allodynia. The brain stem dorsal column nuclei integrate tactile inputs, yet their role in mediating tactile sensitivity and allodynia remains understudied. We found that gracile nucleus (Gr) inhibitory interneurons and thalamus-projecting neurons are differentially innervated by primary afferents and spinal inputs. Functional manipulations of these distinct Gr neuronal populations bidirectionally shifted tactile sensitivity but did not affect noxious mechanical or thermal sensitivity. During neuropathic pain, Gr neurons exhibited increased sensory-evoked activity and asynchronous excitatory drive from primary afferents. Silencing Gr projection neurons or activating Gr inhibitory neurons in neuropathic mice reduced tactile hypersensitivity, and enhancing inhibition ameliorated paw-withdrawal signatures of neuropathic pain and induced conditioned place preference. These results suggest that Gr activity contributes to tactile sensitivity and affective, pain-associated phenotypes of mechanical allodynia.
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Affiliation(s)
- Aman Upadhyay
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Brain Health Institute, Rutgers University, Piscataway, NJ, USA; Graduate Program in Neuroscience, Rutgers Robert Wood Johnson Medical School, Rutgers University, The State University of New Jersey, Piscataway, NJ, USA
| | - Mark A Gradwell
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Brain Health Institute, Rutgers University, Piscataway, NJ, USA
| | - Thomas J Vajtay
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - James Conner
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Arnab A Sanyal
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Chloe Azadegan
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Komal R Patel
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Joshua K Thackray
- Human Genetics Institute of New Jersey, Rutgers University, The State University of New Jersey, Piscataway, NJ, USA
| | - Manon Bohic
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Brain Health Institute, Rutgers University, Piscataway, NJ, USA
| | - Fumiyasu Imai
- Burke Neurological Institute, White Plains, NY, USA; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Simon O Ogundare
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Yutaka Yoshida
- Burke Neurological Institute, White Plains, NY, USA; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Ishmail Abdus-Saboor
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Eiman Azim
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Victoria E Abraira
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Brain Health Institute, Rutgers University, Piscataway, NJ, USA.
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2
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Bertrand M, Karkuszewski M, Kersten R, Orban de Xivry JJ, Pruszynski JA. String-pulling by the common marmoset. J Neurophysiol 2025; 133:1222-1233. [PMID: 40095478 DOI: 10.1152/jn.00561.2024] [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: 11/25/2024] [Revised: 12/24/2024] [Accepted: 03/11/2025] [Indexed: 03/19/2025] Open
Abstract
Coordinated hand movements used to grasp and manipulate objects are crucial for many daily activities, such as tying shoelaces or opening jars. Recently, the string-pulling task, which involves cyclically reaching, grasping, and pulling a string, has been used to study coordinated hand movements in rodents and humans. Here, we characterize how adult common marmosets perform the string-pulling task and describe changes in performance across the lifespan. Marmosets (n = 15, 7 females) performed a string-pulling task for a food reward using an instrumented apparatus attached to their home-cage. Movement kinematics were acquired using markerless video tracking and we assessed individual hand movements and bimanual coordination using standard metrics. Marmosets oriented their gaze toward the string above their hands and readily performed the task regardless of sex or age. The task required little training and animals routinely engaged in multiple pulling trials per session, despite not being under water or food control. All marmosets showed consistent pulling speed and similar hand movements regardless of age. Adult marmosets exhibited a clear hand effect, performing straighter and faster movements with their right hand despite showing idiosyncratic hand preference according to a traditional food retrieval assay. Hand effects were also evident for younger animals but seemed attenuated in the older animals. In terms of bimanual coordination, all adult marmosets demonstrated alternating movement pattern for vertical hand positions. Two younger and two older marmosets exhibited idiosyncratic coordination patterns even after substantial experience. In general, younger and older animals exhibited higher variability in bimanual coordination than adults.NEW & NOTEWORTHY Bimanual coordination is crucial for daily activities. In this study, we characterized how common marmosets performed the string-pulling task without extensive training, regardless of sex or age, and naturally exhibited a cyclical alternating pattern of hand movements. Although the overall behavior was similar across ages, younger and older marmosets demonstrated higher variability in bimanual coordination. These results establish the string-pulling task as a reliable tool for studying bimanual coordination and its underlying neural substrates.
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Affiliation(s)
- Mathilde Bertrand
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
- Western Institute of Neuroscience, Western University, London, Ontario, Canada
| | | | - Rhonda Kersten
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
- Western Institute of Neuroscience, Western University, London, Ontario, Canada
| | - Jean-Jacques Orban de Xivry
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - J Andrew Pruszynski
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
- Western Institute of Neuroscience, Western University, London, Ontario, Canada
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3
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Gilmer JI, Coltman SK, Cuenu G, Hutchinson JR, Huber D, Person AL, Al Borno M. A novel biomechanical model of the proximal mouse forelimb predicts muscle activity in optimal control simulations of reaching movements. J Neurophysiol 2025; 133:1266-1278. [PMID: 40098414 DOI: 10.1152/jn.00499.2024] [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: 10/25/2024] [Revised: 11/19/2024] [Accepted: 03/04/2025] [Indexed: 03/19/2025] Open
Abstract
Mice are key model organisms in neuroscience and motor systems physiology. Fine motor control tasks performed by mice have become widely used in assaying neural and biophysical motor system mechanisms. Although fine motor tasks provide useful insights into behaviors that require complex multi-joint motor control, there is no previously developed physiological biomechanical model of the adult mouse forelimb available for estimating kinematics, muscle activity, or kinetics during behaviors. Here, we developed a musculoskeletal model based on high-resolution imaging of the mouse forelimb that includes muscles spanning the neck, trunk, shoulder, and limbs. Physics-based optimal control simulations of the forelimb model were used to estimate in vivo muscle activity present when constrained to the tracked kinematics during reaching movements. The activity of a subset of muscles was recorded and used to assess the accuracy of the muscle patterning in simulation. We found that the synthesized muscle patterning in the forelimb model had a strong resemblance to empirical muscle patterning, suggesting that our model has utility in providing a realistic set of estimated muscle excitations over time when given a kinematic template. The strength of the similarity between empirical muscle activity and optimal control predictions increases as mice performance improves throughout learning of the reaching task. Our computational tools are available as open-source in the OpenSim physics and modeling platform. Our model can enhance research into limb control across broad research topics and can inform analyses of motor learning, muscle synergies, neural patterning, and behavioral research that would otherwise be inaccessible.NEW & NOTEWORTHY Investigations into motor planning and execution lack an accurate and complete model of the forelimb, which could bolster or expand on findings. We sought to construct such a model using high-detail scans of murine anatomy and prior research into muscle physiology. We then used the model to predict muscle excitations in a set of reaching movements and found that it provided accurate estimations and provided insight into an optimal-control framework of motor learning.
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Affiliation(s)
- Jesse I Gilmer
- Department of Computer Science and Engineering, Computational Bioscience Program, University of Colorado Denver | Anschutz Medical Campus, Denver, Colorado, United States
| | - Susan K Coltman
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Geraldine Cuenu
- Department of Basic Neuroscience, University of Geneva, Geneva, Switzerland
| | - John R Hutchinson
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
| | - Daniel Huber
- Department of Basic Neuroscience, University of Geneva, Geneva, Switzerland
| | - Abigail L Person
- Department of Physiology and Biophysics, University of Colorado Denver | Anschutz Medical Campus, Denver, Colorado, United States
| | - Mazen Al Borno
- Department of Computer Science and Engineering, Computational Bioscience Program, University of Colorado Denver | Anschutz Medical Campus, Denver, Colorado, United States
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Kaiser J, Patel P, Fedde S, Lammers A, Kenwood MR, Iqbal A, Goldberg M, Sahni V. Developmental molecular signatures define de novo cortico-brainstem circuit for skilled forelimb movement. RESEARCH SQUARE 2025:rs.3.rs-6150344. [PMID: 40196004 PMCID: PMC11975033 DOI: 10.21203/rs.3.rs-6150344/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2025]
Abstract
Skilled movement relies on descending cortical projections to the brainstem and spinal cord. While corticospinal neurons (CSN) have long been recognized for their role in fine motor control, the contribution of cortical projections to the brainstem remains poorly understood. Here, we identify a previously unrecognized direct cortico-brainstem circuit that emerges early in development and persists into adulthood. A subset of subcerebral projection neurons (SCPN) limit their projections to the brainstem from the earliest stages of axon extension without ever extending to the spinal cord. Using FACS purification and single-cell RNA sequencing, we show that these cortico-brainstem neurons (CBN) can be prospectively identified by the expression of Neuropeptide Y (Npy) in development. Functional silencing of Npy+ CBN in adulthood leads to impaired skilled forelimb reaching, demonstrating their essential role in adult motor control. Npy+ CBN project preferentially to rostral brainstem regions, including the midbrain reticular formation. These findings reveal developmental molecular signatures that define cortico-brainstem pathways for adult skilled movement. Our work provides new insights into the developmental logic that establishes descending cortical circuits and opens avenues for targeted investigation of their roles in motor function and recovery after injury.
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Affiliation(s)
- Julia Kaiser
- Burke Neurological Institute, White Plains, NY, 10605
| | - Payal Patel
- Burke Neurological Institute, White Plains, NY, 10605
| | - Sam Fedde
- Burke Neurological Institute, White Plains, NY, 10605
| | | | | | - Asim Iqbal
- Burke Neurological Institute, White Plains, NY, 10605
- Tibbling Technologies, Redmond, WA, 98052
| | - Mark Goldberg
- Department of Neurology, UT Health Sciences Center San Antonio, San Antonio, TX, USA
| | - Vibhu Sahni
- Burke Neurological Institute, White Plains, NY, 10605
- Department of Neurology, UT Health Sciences Center San Antonio, San Antonio, TX, USA
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York City, NY, 10065
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5
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Chaterji S, Belliappa PH, Sathyamurthy A. The superior colliculus directs goal-oriented forelimb movements. Cell Rep 2025; 44:115097. [PMID: 39723891 DOI: 10.1016/j.celrep.2024.115097] [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: 07/11/2024] [Revised: 10/23/2024] [Accepted: 12/02/2024] [Indexed: 12/28/2024] Open
Abstract
Skilled forelimb control is essential for daily living, yet our understanding of its neural mechanisms, although extensive, remains incomplete. Here, we present evidence that the superior colliculus (SC), a major midbrain structure, is necessary for accurate forelimb reaching in mice. We found that neurons in the lateral SC are active during goal-directed reaching, and by employing chemogenetic and phase-specific optogenetic silencing of these neurons, we show that the SC causally facilitates reach accuracy. Anatomical studies identified the deep cerebellar nuclei and substantia nigra pars reticulata as sources of inputs to the SC, while functional studies revealed a role for nigrotectal, but not cerebellotectal, neurons in controlling reach endpoints. Silencing the nigrotectal pathway caused paw deviations opposite to those seen with SC silencing, emphasizing the coordinated role of the substantia nigra and SC in regulating optimal reaching. Together, these findings establish the SC as a crucial regulator of skilled forelimb control.
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Affiliation(s)
- Shrivas Chaterji
- Centre for Neuroscience, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Punarva H Belliappa
- Centre for Neuroscience, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Anupama Sathyamurthy
- Centre for Neuroscience, Indian Institute of Science, Bengaluru, Karnataka 560012, India.
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6
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Klatzky RL. Haptic Perception and Its Relation to Action. Annu Rev Psychol 2025; 76:227-250. [PMID: 39322436 DOI: 10.1146/annurev-psych-011624-101129] [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] [Indexed: 09/27/2024]
Abstract
Haptic perception uses signals from touch receptors to detect, locate, and mentally represent objects and surfaces. Research from behavioral science, neuroscience, and computational modeling advances understanding of these essential functions. Haptic perception is grounded in neural circuitry that transmits external contact to the brain via increasingly abstracted representations. Computational models of mechanical interactions at the skin predict peripheral neural firing rates that initiate the processing chain. Behavioral phenomena and associated neural processes illustrate the reciprocal relationship by which perception supports action and action gates experience. The interaction of sensation and action is evident in how features of surfaces and objects such as softness and curvature are encoded. By incorporating touch sensations in conjunction with motor control, biologically embedded prosthetics enhance user capabilities and may elicit feelings of ownership. Efforts to create virtual haptic experience with advanced technologies underscore the complexity of this fundamental perceptual channel and its relation to action.
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Affiliation(s)
- Roberta L Klatzky
- Department of Psychology, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA;
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7
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Lee KS, Loutit AJ, de Thomas Wagner D, Sanders M, Huber D. Emergence of a brainstem somatosensory tonotopic map for substrate vibration. Nat Neurosci 2025; 28:97-104. [PMID: 39548325 DOI: 10.1038/s41593-024-01821-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 10/15/2024] [Indexed: 11/17/2024]
Abstract
Perceiving substrate-borne vibrations is a fundamental component of tactile perception. How location (somatotopy) and frequency tuning (tonotopy) of vibrations are integratively processed is poorly understood. Here we addressed this question using in vivo electrophysiology and two-photon calcium imaging along the dorsal column-medial lemniscal pathway. We found that both frequency and location are organized into structured maps in the dorsal column nuclei (DCN). Both maps are intimately related at the fine spatial scale, with parallel map gradients that are consistent across the depth of the DCN and preserved along the ascending pathway. The tonotopic map only partially reflects the distribution of end organs in the skin and deep tissue; instead, the emergence of the fine-scale tonotopy is due to the selective dendritic sampling from axonal afferents, already at the first synaptic relay. We conclude that DCN neural circuits are key to the emergence of these two fine-scale topographical organizations in early somatosensory pathways.
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Affiliation(s)
- Kuo-Sheng Lee
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland.
- Institute of Biomedical Sciences, Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, Taiwan.
| | - Alastair J Loutit
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
| | | | - Mark Sanders
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
- Institute of Biomedical Sciences, Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, Taiwan
| | - Daniel Huber
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland.
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8
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Alasoadura M, Leclerc J, Hazime M, Leprince J, Vaudry D, Chuquet J. The Excessive Tonic Inhibition of the Peri-infarct Cortex Depresses Low Gamma Rhythm Power During Poststroke Recovery. J Neurosci 2024; 44:e1482232024. [PMID: 39406519 PMCID: PMC11622182 DOI: 10.1523/jneurosci.1482-23.2024] [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: 07/26/2023] [Revised: 08/02/2024] [Accepted: 09/09/2024] [Indexed: 12/06/2024] Open
Abstract
The cortex immediately surrounding a brain ischemic lesion, the peri-infarct cortex (PIC), harbors a large part of the potential to recover lost functions. However, our understanding of the neurophysiological conditions in which synaptic plasticity operates remains limited. Here we hypothesized that the chronic imbalance between excitation and inhibition of the PIC prevents the normalization of the gamma rhythm, a waveband of neural oscillations thought to orchestrate action potential trafficking. Probing the local field potential activity of the forelimb primary sensory cortex (S1FL) located in the PIC of male adult mice, we found a constant, deep reduction of low-gamma oscillation power (L-gamma; 30-50 Hz) precisely during the critical time window for recovery (1-3 weeks after stroke). The collapse of L-gamma power negatively correlated with behavioral progress in affected forelimb use. Mapping astrocyte reactivity and GABA-like immunoreactivity in the PIC revealed a parallel high signal, which gradually increased when approaching the lesion. Increasing tonic inhibition with local infusion of GABA or by blocking its recapture reduced L-gamma oscillation power in a magnitude similar to stroke. Conversely, the negative allosteric modulation of tonic GABA conductance using L655,708 or the gliopeptide ODN rescued the L-gamma power of the PIC. Altogether the present data point out that the chronic excess of ambient GABA in the PIC limits the generation of L-gamma oscillations in the repairing cortex and suggests that rehabilitative interventions aimed at normalizing low-gamma power within the critical period of stroke recovery could optimize the restitution of lost functions.
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Affiliation(s)
- Michael Alasoadura
- Univ Rouen Normandie, Normandie Univ, GRHVN UR3830, F-76000 Rouen, France
- Univ Rouen Normandie, Inserm, Normandie Univ, NORDIC UMR 1239, F-76000 Rouen, France
| | - Juliette Leclerc
- Univ Rouen Normandie, Normandie Univ, GRHVN UR3830, F-76000 Rouen, France
| | - Mahmoud Hazime
- Univ Rouen Normandie, Inserm, Normandie Univ, NORDIC UMR 1239, F-76000 Rouen, France
| | - Jérôme Leprince
- Univ Rouen Normandie, Inserm, Normandie Univ, NORDIC UMR 1239, F-76000 Rouen, France
| | - David Vaudry
- Univ Rouen Normandie, Inserm, Normandie Univ, NORDIC UMR 1239, F-76000 Rouen, France
| | - Julien Chuquet
- Univ Rouen Normandie, Normandie Univ, GRHVN UR3830, F-76000 Rouen, France
- Univ Rouen Normandie, Inserm, Normandie Univ, NORDIC UMR 1239, F-76000 Rouen, France
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9
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Greenspon CM, Shelchkova ND, Hobbs TG, Bensmaia SJ, Gaunt RA. Intracortical microstimulation of human somatosensory cortex induces natural perceptual biases. Brain Stimul 2024; 17:1178-1185. [PMID: 39413869 PMCID: PMC11887563 DOI: 10.1016/j.brs.2024.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 09/09/2024] [Accepted: 10/10/2024] [Indexed: 10/18/2024] Open
Abstract
Time-order error, a psychophysical phenomenon in which the duration in between successive stimuli alters perception, has been studied for decades by neuroscientists and psychologists. To date, however, the locus of these effects is unknown. We use intracortical microstimulation of somatosensory cortex in three humans with spinal cord injury as a tool to bypass initial stages of processing and restrict the possible locations that signals could be modified. Using a 2-interval forced choice amplitude discrimination paradigm, we first assessed the extent to which order effects are observed. Comparing trials where the standard stimulus was in the first or second interval, we found that systematic biases are exhibited, typically causing the intensity of the second stimulus to be overestimated The degree of this overestimation for individual electrodes was dependent on the perceptual sensitivity to changes in stimulus amplitude. To investigate the role of memory on this phenomenon, we implemented a 2-interval magnitude estimation task in which participants were instructed to ignore the first stimulus and again found that the perceptual intensity of the second stimulus tended to be enhanced by the first in a manner that depended on the amplitude and duration of the first stimulus. Finally, we repeated both paradigms while varying the inter-stimulus interval to examine the timescale over which these effects occur and found that longer inter-stimulus intervals reduced the effect size. These results show that direct activation of primary somatosensory cortex is sufficient to induce time-order errors.
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Affiliation(s)
- Charles M Greenspon
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA.
| | - Natalya D Shelchkova
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA
| | - Taylor G Hobbs
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sliman J Bensmaia
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA; Committee on Computational Neuroscience, University of Chicago, Chicago, IL, USA; Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Robert A Gaunt
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
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10
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Gilmer JI, Coltman SK, Cuenu G, Hutchinson JR, Huber D, Person AL, Al Borno M. A novel biomechanical model of the mouse forelimb predicts muscle activity in optimal control simulations of reaching movements. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.05.611289. [PMID: 39314302 PMCID: PMC11418950 DOI: 10.1101/2024.09.05.611289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Mice are key model organisms in neuroscience and motor systems physiology. Fine motor control tasks performed by mice have become widely used in assaying neural and biophysical motor system mechanisms. Although fine motor tasks provide useful insights into behaviors which require complex multi-joint motor control, there is no previously developed physiological biomechanical model of the adult mouse forelimb available for estimating kinematics nor muscle activity or kinetics during behaviors. Here, we developed a musculoskeletal model based on high-resolution imaging of the mouse forelimb that includes muscles spanning the neck, trunk, shoulder, and limbs. Physics-based optimal control simulations of the forelimb model were used to estimate in vivo muscle activity present when constrained to the tracked kinematics during reaching movements. The activity of a subset of muscles was recorded and used to assess the accuracy of the muscle patterning in simulation. We found that the synthesized muscle patterning in the forelimb model had a strong resemblance to empirical muscle patterning, suggesting that our model has utility in providing a realistic set of estimated muscle excitations over time when given a kinematic template. The strength of the similarity between empirical muscle activity and optimal control predictions increases as mice performance improves throughout learning of the reaching task. Our computational tools are available as open-source in the OpenSim physics and modeling platform. Our model can enhance research into limb control across broad research topics and can inform analyses of motor learning, muscle synergies, neural patterning, and behavioral research that would otherwise be inaccessible.
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Affiliation(s)
- Jesse I Gilmer
- University of Colorado Denver ∣ Anschutz Medical Campus, Department of Computer Science and Engineering, Computational Bioscience Program
| | - Susan K Coltman
- The Pennsylvania State University, Department of Kinesiology
| | | | - John R Hutchinson
- Royal Veterinary College, Department of Comparative Biomedical Sciences
| | - Daniel Huber
- University of Geneva, Department of Basic Neuroscience
| | - Abigail L Person
- University of Colorado Denver ∣ Anschutz Medical Campus, Department of Physiology and Biophysics
| | - Mazen Al Borno
- University of Colorado Denver ∣ Anschutz Medical Campus, Department of Computer Science and Engineering, Computational Bioscience Program
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11
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Skrobot M, Sa RD, Walter J, Vogt A, Paulat R, Lips J, Mosch L, Mueller S, Dominiak S, Sachdev R, Boehm-Sturm P, Dirnagl U, Endres M, Harms C, Wenger N. Refined movement analysis in the staircase test reveals differential motor deficits in mouse models of stroke. J Cereb Blood Flow Metab 2024; 44:1551-1564. [PMID: 39234984 PMCID: PMC11418716 DOI: 10.1177/0271678x241254718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 03/05/2024] [Accepted: 04/22/2024] [Indexed: 09/06/2024]
Abstract
Accurate assessment of post-stroke deficits is crucial in translational research. Recent advances in machine learning offer precise quantification of rodent motor behavior post-stroke, yet detecting lesion-specific upper extremity deficits remains unclear. Employing proximal middle cerebral artery occlusion (MCAO) and cortical photothrombosis (PT) in mice, we assessed post-stroke impairments via the Staircase test. Lesion locations were identified using 7 T-MRI. Machine learning was applied to reconstruct forepaw kinematic trajectories and feature analysis was achieved with MouseReach, a new data-processing toolbox. Lesion reconstructions pinpointed ischemic centers in the striatum (MCAO) and sensorimotor cortex (PT). Pellet retrieval alterations were observed, but were unrelated to overall stroke volume. Instead, forepaw slips and relative reaching success correlated with increasing cortical lesion size in both models. Striatal lesion size after MCAO was associated with prolonged reach durations that occurred with delayed symptom onset. Further analysis on the impact of selective serotonin reuptake inhibitors in the PT model revealed no clear treatment effects but replicated strong effect sizes of slips for post-stroke deficit detection. In summary, refined movement analysis unveiled specific deficits in two widely-used mouse stroke models, emphasizing the value of deep behavioral profiling in preclinical stroke research to enhance model validity for clinical translation.
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Affiliation(s)
- Matej Skrobot
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Rafael De Sa
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Josefine Walter
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- QUEST Center for Transforming Biomedical Research, Berlin Institute of Health (BIH), Berlin, Germany
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Arend Vogt
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Raik Paulat
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Janet Lips
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Larissa Mosch
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Susanne Mueller
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence and Charité Core Facility 7T Experimental MRIs, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sina Dominiak
- Institute of Biology, Humboldt University of Berlin, Berlin, Germany
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, UK
| | - Robert Sachdev
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, UK
| | - Philipp Boehm-Sturm
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence and Charité Core Facility 7T Experimental MRIs, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ulrich Dirnagl
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- QUEST Center for Transforming Biomedical Research, Berlin Institute of Health (BIH), Berlin, Germany
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany
- DZHK (German Center for Cardiovascular Research), Berlin, Germany
- DZNE (German Center for Neurodegenerative Diseases), Berlin, Germany
| | - Matthias Endres
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany
- DZHK (German Center for Cardiovascular Research), Berlin, Germany
- DZNE (German Center for Neurodegenerative Diseases), Berlin, Germany
- DZPG (German Center of Mental Health), Berlin, Germany
| | - Christoph Harms
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany
- DZHK (German Center for Cardiovascular Research), Berlin, Germany
| | - Nikolaus Wenger
- Department of Neurology with Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
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12
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Kirk EA, Hope KT, Sober SJ, Sauerbrei BA. An output-null signature of inertial load in motor cortex. Nat Commun 2024; 15:7309. [PMID: 39181866 PMCID: PMC11344817 DOI: 10.1038/s41467-024-51750-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 08/15/2024] [Indexed: 08/27/2024] Open
Abstract
Coordinated movement requires the nervous system to continuously compensate for changes in mechanical load across different conditions. For voluntary movements like reaching, the motor cortex is a critical hub that generates commands to move the limbs and counteract loads. How does cortex contribute to load compensation when rhythmic movements are sequenced by a spinal pattern generator? Here, we address this question by manipulating the mass of the forelimb in unrestrained mice during locomotion. While load produces changes in motor output that are robust to inactivation of motor cortex, it also induces a profound shift in cortical dynamics. This shift is minimally affected by cerebellar perturbation and significantly larger than the load response in the spinal motoneuron population. This latent representation may enable motor cortex to generate appropriate commands when a voluntary movement must be integrated with an ongoing, spinally-generated rhythm.
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Affiliation(s)
- Eric A Kirk
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Keenan T Hope
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Samuel J Sober
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Britton A Sauerbrei
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
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13
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Yoshinaga Y, Sato N. Reach-to-Grasp and tactile discrimination task: A new task for the study of sensory-motor learning. Behav Brain Res 2024; 466:115007. [PMID: 38648867 DOI: 10.1016/j.bbr.2024.115007] [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: 01/30/2024] [Revised: 04/04/2024] [Accepted: 04/19/2024] [Indexed: 04/25/2024]
Abstract
Although active touch in rodents arises from the forepaws as well as whiskers, most research on active touch only focuses on whiskers. This results in a paucity of tasks designed to assess the process of active touch with a forepaw. We develop a new experimental task, the Reach-to-Grasp and Tactile Discrimination task (RGTD task), to examine active touch with a forepaw in rodents, particularly changes in processes of active touch during motor skill learning. In the RGTD task, animals are required to (1) extend their forelimb to an object, (2) grasp the object, and (3) manipulate the grasped object with the forelimb. The animals must determine the direction of the manipulation based on active touch sensations arising during the period of the grasping. In experiment 1 of the present study, we showed that rats can learn the RGTD task. In experiment 2, we confirmed that the rats are capable of reversal learning of the RGTD task. The RGTD task shared most of the reaching movements involved with conventional forelimb reaching tasks. From the standpoint of a discrimination task, the RGTD task enables rigorous experimental control, for example by removing bias in the stimulus-response correspondence, and makes it possible to utilize diverse experimental procedures that have been difficult in prior tasks.
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Affiliation(s)
- Yudai Yoshinaga
- Department of Psychological Sciences, Kwansei Gakuin University, 1-1-155, Uegahara, Nishinomiya, Hyogo 662-8501, Japan; Research Fellow of Japan Society for the Promotion of Science, Japan
| | - Nobuya Sato
- Department of Psychological Sciences, Kwansei Gakuin University, 1-1-155, Uegahara, Nishinomiya, Hyogo 662-8501, Japan; Center for Applied Psychological Science (CAPS), Kwansei Gakuin University, 1-1-155, Uegahara, Nishinomiya, Hyogo, Japan.
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14
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Upadhyay A, Gradwell MA, Vajtay TJ, Conner J, Sanyal AA, Azadegan C, Patel KR, Thackray JK, Bohic M, Imai F, Ogundare SO, Yoshida Y, Abdus-Saboor I, Azim E, Abraira VE. The Dorsal Column Nuclei Scale Mechanical Sensitivity in Naive and Neuropathic Pain States. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.20.581208. [PMID: 38712022 PMCID: PMC11071288 DOI: 10.1101/2024.02.20.581208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Tactile perception relies on reliable transmission and modulation of low-threshold information as it travels from the periphery to the brain. During pathological conditions, tactile stimuli can aberrantly engage nociceptive pathways leading to the perception of touch as pain, known as mechanical allodynia. Two main drivers of peripheral tactile information, low-threshold mechanoreceptors (LTMRs) and postsynaptic dorsal column neurons (PSDCs), terminate in the brainstem dorsal column nuclei (DCN). Activity within the DRG, spinal cord, and DCN have all been implicated in mediating allodynia, yet the DCN remains understudied at the cellular, circuit, and functional levels compared to the other two. Here, we show that the gracile nucleus (Gr) of the DCN mediates tactile sensitivity for low-threshold stimuli and contributes to mechanical allodynia during neuropathic pain in mice. We found that the Gr contains local inhibitory interneurons in addition to thalamus-projecting neurons, which are differentially innervated by primary afferents and spinal inputs. Functional manipulations of these distinct Gr neuronal populations resulted in bidirectional changes to tactile sensitivity, but did not affect noxious mechanical or thermal sensitivity. During neuropathic pain, silencing Gr projection neurons or activating Gr inhibitory neurons was able to reduce tactile hypersensitivity, and enhancing inhibition was able to ameliorate paw withdrawal signatures of neuropathic pain, like shaking. Collectively, these results suggest that the Gr plays a specific role in mediating hypersensitivity to low-threshold, innocuous mechanical stimuli during neuropathic pain, and that Gr activity contributes to affective, pain-associated phenotypes of mechanical allodynia. Therefore, these brainstem circuits work in tandem with traditional spinal circuits underlying allodynia, resulting in enhanced signaling of tactile stimuli in the brain during neuropathic pain.
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Affiliation(s)
- Aman Upadhyay
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
- Neuroscience PhD program at Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Mark A Gradwell
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
| | - Thomas J Vajtay
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - James Conner
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Arnab A Sanyal
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Chloe Azadegan
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Komal R Patel
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Joshua K Thackray
- Human Genetics Institute of New Jersey, Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Manon Bohic
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
| | - Fumiyasu Imai
- Burke Neurological Institute, White Plains, New York City, New York, USA
- Brain and Mind Research Institute, Weill Cornell Medicine, New York City, New York, USA
| | - Simon O Ogundare
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Department of Biological Sciences, Columbia University, New York City, New York, USA
| | - Yutaka Yoshida
- Burke Neurological Institute, White Plains, New York City, New York, USA
- Brain and Mind Research Institute, Weill Cornell Medicine, New York City, New York, USA
| | - Ishmail Abdus-Saboor
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Department of Biological Sciences, Columbia University, New York City, New York, USA
| | - Eiman Azim
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Victoria E Abraira
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
- Lead contact
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15
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Greenspon CM, Shelchkova ND, Hobbs TG, Bensmaia SJ, Gaunt RA. Intracortical microstimulation of human somatosensory cortex is sufficient to induce perceptual biases. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.04.19.24305901. [PMID: 38712172 PMCID: PMC11071569 DOI: 10.1101/2024.04.19.24305901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Time-order error, a psychophysical phenomenon in which the duration in between successive stimuli alters perception, has been studied for decades by neuroscientists and psychologists. To date, however, the locus of these effects is unknown. We use intracortical microstimulation of somatosensory cortex in humans as a tool to bypass initial stages of processing and restrict the possible locations that signals could be modified. We find that, using both amplitude discrimination and magnitude estimation paradigms, intracortical microstimulation reliably evoked time-order errors across all participants. Points of subjective equality were symmetrically shifted during amplitude discrimination experiments and the intensity of a successive stimulus was perceived as being more intense when compared to single stimulus trials in magnitude estimation experiments. The error was reduced for both paradigms at longer inter-stimulus intervals. These results show that direct activation of primary somatosensory cortex is sufficient to induce time-order errors.
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Affiliation(s)
- Charles M. Greenspon
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL
| | | | - Taylor G. Hobbs
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA
| | - Sliman J. Bensmaia
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL
- Neuroscience Institute, University of Chicago, Chicago, IL
| | - Robert A. Gaunt
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA
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16
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Kubota S, Sasaki C, Kikuta S, Yoshida J, Ito S, Gomi H, Oya T, Seki K. Modulation of somatosensory signal transmission in the primate cuneate nucleus during voluntary hand movement. Cell Rep 2024; 43:113884. [PMID: 38458194 DOI: 10.1016/j.celrep.2024.113884] [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: 04/27/2023] [Revised: 01/02/2024] [Accepted: 02/14/2024] [Indexed: 03/10/2024] Open
Abstract
Primate hands house an array of mechanoreceptors and proprioceptors, which are essential for tactile and kinematic information crucial for daily motor action. While the regulation of these somatosensory signals is essential for hand movements, the specific central nervous system (CNS) location and mechanism remain unclear. Our study demonstrates the attenuation of somatosensory signals in the cuneate nucleus during voluntary movement, suggesting significant modulation at this initial relay station in the CNS. The attenuation is comparable to the cerebral cortex but more pronounced than in the spinal cord, indicating the cuneate nuclei's role in somatosensory perception modulation during movement. Moreover, our findings suggest that the descending motor tract may regulate somatosensory transmission in the cuneate nucleus, enhancing relevant signals and suppressing unnecessary ones for the regulation of movement. This process of recurrent somatosensory modulation between cortical and subcortical areas could be a basic mechanism for modulating somatosensory signals to achieve active perception.
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Affiliation(s)
- Shinji Kubota
- Department of Neurophysiology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan
| | - Chika Sasaki
- Department of Neurophysiology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan
| | - Satomi Kikuta
- Department of Neurophysiology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan
| | - Junichiro Yoshida
- Department of Neurophysiology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan
| | - Sho Ito
- NTT Communication Science Laboratories, Nippon Telegraph and Telephone Co., Atsugi, Kanagawa 243-0198, Japan
| | - Hiroaki Gomi
- NTT Communication Science Laboratories, Nippon Telegraph and Telephone Co., Atsugi, Kanagawa 243-0198, Japan
| | - Tomomichi Oya
- Department of Neurophysiology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan
| | - Kazuhiko Seki
- Department of Neurophysiology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan.
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17
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Cai NM, Medina EG, Gonzalez S, Duong A, Gurari N. Impact of Arm Dominance and Location on Detecting Electrotactile Stimuli During Voluntary Motor Activation in Older Adults. IEEE TRANSACTIONS ON HAPTICS 2023; 16:484-490. [PMID: 37074882 PMCID: PMC11403864 DOI: 10.1109/toh.2023.3268203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Activation-related sensory gating is important for sensorimotor control, filtering signals irrelevant to a task. Literature on brain lateralization suggests that motor activation patterns during sensorimotor control differ depending on arm dominance. Whether the lateralization effect extends to how sensory signals modulate during voluntary sensorimotor control remains unaddressed. We compared tactile sensory gating during voluntary motor activation between the arms of older adults. Eight right-arm dominant participants received a single-pulse, 100 μs square-wave electrotactile stimulus at their testing arm's fingertip or elbow. We identified at both arms the threshold at which the electrotactile stimulus was detected when participants were at rest (baseline) and isometrically flexing about the elbow to 25% and 50% of their maximum voluntary torque. Results reveal a difference in the detection threshold at the fingertip (p 0.001) between the arms, yet not the elbow (p = 0.264). Additionally, results demonstrate that greater isometric flexion about the elbow yields increased detection thresholds at the elbow (p = 0.005), yet not the fingertip (p = 0.069). However, the changes in detection threshold during motor activation did not significantly differ between the arms (p = 0.154). The findings regarding an impact of arm dominance and location on tactile perception are important when considering sensorimotorhaptic perception and training, including post-unilateral injury.
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Affiliation(s)
- Ninghe M. Cai
- NMC, SG, AG, and NG are with the Department of Physical Therapy and Human Movement Sciences, Northwestern University, 645 N Michigan Ave Suite 1100, Chicago, IL, 60611, USA
| | - Eileen G. Medina
- EGM and NG are with the Department of Biomedical Engineering & Mechanics, Virginia Polytechnic Institute and State University, 495 Old Turner St, Blacksburg, VA, 24061, USA
| | - Stefani Gonzalez
- NMC, SG, AG, and NG are with the Department of Physical Therapy and Human Movement Sciences, Northwestern University, 645 N Michigan Ave Suite 1100, Chicago, IL, 60611, USA
| | - Alan Duong
- NMC, SG, AG, and NG are with the Department of Physical Therapy and Human Movement Sciences, Northwestern University, 645 N Michigan Ave Suite 1100, Chicago, IL, 60611, USA
| | - Netta Gurari
- NMC, SG, AG, and NG are with the Department of Physical Therapy and Human Movement Sciences, Northwestern University, 645 N Michigan Ave Suite 1100, Chicago, IL, 60611, USA
- EGM and NG are with the Department of Biomedical Engineering & Mechanics, Virginia Polytechnic Institute and State University, 495 Old Turner St, Blacksburg, VA, 24061, USA
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18
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Butler DJ, Keim AP, Ray S, Azim E. Large-scale capture of hidden fluorescent labels for training generalizable markerless motion capture models. Nat Commun 2023; 14:5866. [PMID: 37752123 PMCID: PMC10522643 DOI: 10.1038/s41467-023-41565-3] [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: 05/30/2022] [Accepted: 09/08/2023] [Indexed: 09/28/2023] Open
Abstract
Deep learning-based markerless tracking has revolutionized studies of animal behavior. Yet the generalizability of trained models tends to be limited, as new training data typically needs to be generated manually for each setup or visual environment. With each model trained from scratch, researchers track distinct landmarks and analyze the resulting kinematic data in idiosyncratic ways. Moreover, due to inherent limitations in manual annotation, only a sparse set of landmarks are typically labeled. To address these issues, we developed an approach, which we term GlowTrack, for generating orders of magnitude more training data, enabling models that generalize across experimental contexts. We describe: a) a high-throughput approach for producing hidden labels using fluorescent markers; b) a multi-camera, multi-light setup for simulating diverse visual conditions; and c) a technique for labeling many landmarks in parallel, enabling dense tracking. These advances lay a foundation for standardized behavioral pipelines and more complete scrutiny of movement.
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Affiliation(s)
- Daniel J Butler
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Alexander P Keim
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Shantanu Ray
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Eiman Azim
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA.
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19
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Elbaz MA, Demers M, Kleinfeld D, Ethier C, Deschênes M. Interchangeable Role of Motor Cortex and Reafference for the Stable Execution of an Orofacial Action. J Neurosci 2023; 43:5521-5536. [PMID: 37400255 PMCID: PMC10376937 DOI: 10.1523/jneurosci.2089-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 06/25/2023] [Accepted: 06/27/2023] [Indexed: 07/05/2023] Open
Abstract
Animals interact with their environment through mechanically active, mobile sensors. The efficient use of these sensory organs implies the ability to track their position; otherwise, perceptual stability or prehension would be profoundly impeded. The nervous system may keep track of the position of a sensorimotor organ via two complementary feedback mechanisms-peripheral reafference (external, sensory feedback) and efference copy (internal feedback). Yet, the potential contributions of these mechanisms remain largely unexplored. By training male rats to place one of their vibrissae within a predetermined angular range without contact, a task that depends on knowledge of vibrissa position relative to their face, we found that peripheral reafference is not required. The presence of motor cortex is not required either, except in the absence of peripheral reafference to maintain motor stability. Finally, the red nucleus, which receives descending inputs from motor cortex and cerebellum and projects to facial motoneurons, is critically involved in the execution of the vibrissa positioning task. All told, our results point toward the existence of an internal model that requires either peripheral reafference or motor cortex to optimally drive voluntary motion.SIGNIFICANCE STATEMENT How does an animal know where a mechanically active, mobile sensor lies relative to its body? We address this basic question in sensorimotor integration using the motion of the vibrissae in rats. We show that rats can learn to reliably position their vibrissae in the absence of sensory feedback or in the absence of motor cortex. Yet, when both sensory feedback and motor cortex are absent, motor precision is degraded. This suggests the existence of an internal model able to operate in closed- and open-loop modes, requiring either motor cortex or sensory feedback to maintain motor stability.
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Affiliation(s)
- Michaël A Elbaz
- CERVO Brain Research Center, Laval University, Québec City, Québec G1J 2G3, Canada
| | - Maxime Demers
- CERVO Brain Research Center, Laval University, Québec City, Québec G1J 2G3, Canada
| | - David Kleinfeld
- Departments of Physics
- Neurobiology, University of California, San Diego, La Jolla, California 92093
| | - Christian Ethier
- CERVO Brain Research Center, Laval University, Québec City, Québec G1J 2G3, Canada
| | - Martin Deschênes
- CERVO Brain Research Center, Laval University, Québec City, Québec G1J 2G3, Canada
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20
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Alonso I, Scheer I, Palacio-Manzano M, Frézel-Jacob N, Philippides A, Prsa M. Peripersonal encoding of forelimb proprioception in the mouse somatosensory cortex. Nat Commun 2023; 14:1866. [PMID: 37045825 PMCID: PMC10097678 DOI: 10.1038/s41467-023-37575-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 03/23/2023] [Indexed: 04/14/2023] Open
Abstract
Conscious perception of limb movements depends on proprioceptive neural responses in the somatosensory cortex. In contrast to tactile sensations, proprioceptive cortical coding is barely studied in the mammalian brain and practically non-existent in rodent research. To understand the cortical representation of this important sensory modality we developed a passive forelimb displacement paradigm in behaving mice and also trained them to perceptually discriminate where their limb is moved in space. We delineated the rodent proprioceptive cortex with wide-field calcium imaging and optogenetic silencing experiments during behavior. Our results reveal that proprioception is represented in both sensory and motor cortical areas. In addition, behavioral measurements and responses of layer 2/3 neurons imaged with two-photon microscopy reveal that passive limb movements are both perceived and encoded in the mouse cortex as a spatial direction vector that interfaces the limb with the body's peripersonal space.
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Affiliation(s)
- Ignacio Alonso
- Department of Neuroscience and Movement Science, University of Fribourg, Fribourg, Switzerland
| | - Irina Scheer
- Department of Neuroscience and Movement Science, University of Fribourg, Fribourg, Switzerland
| | - Mélanie Palacio-Manzano
- Department of Neuroscience and Movement Science, University of Fribourg, Fribourg, Switzerland
| | - Noémie Frézel-Jacob
- Department of Neuroscience and Movement Science, University of Fribourg, Fribourg, Switzerland
| | - Antoine Philippides
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
| | - Mario Prsa
- Department of Neuroscience and Movement Science, University of Fribourg, Fribourg, Switzerland.
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21
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Li KP, Wu JJ, Zhou ZL, Xu DS, Zheng MX, Hua XY, Xu JG. Noninvasive Brain Stimulation for Neurorehabilitation in Post-Stroke Patients. Brain Sci 2023; 13:brainsci13030451. [PMID: 36979261 PMCID: PMC10046557 DOI: 10.3390/brainsci13030451] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/26/2023] [Accepted: 02/27/2023] [Indexed: 03/09/2023] Open
Abstract
Characterized by high morbidity, mortality, and disability, stroke usually causes symptoms of cerebral hypoxia due to a sudden blockage or rupture of brain vessels, and it seriously threatens human life and health. Rehabilitation is the essential treatment for post-stroke patients suffering from functional impairments, through which hemiparesis, aphasia, dysphagia, unilateral neglect, depression, and cognitive dysfunction can be restored to various degrees. Noninvasive brain stimulation (NIBS) is a popular neuromodulatory technology of rehabilitation focusing on the local cerebral cortex, which can improve clinical functions by regulating the excitability of corresponding neurons. Increasing evidence has been obtained from the clinical application of NIBS, especially repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS). However, without a standardized protocol, existing studies on NIBS show a wide variation in terms of stimulation site, frequency, intensity, dosage, and other parameters. Its application for neurorehabilitation in post-stroke patients is still limited. With advances in neuronavigation technologies, functional near-infrared spectroscopy, and functional MRI, specific brain regions can be precisely located for stimulation. On the basis of our further understanding on neural circuits, neuromodulation in post-stroke rehabilitation has also evolved from single-target stimulation to co-stimulation of two or more targets, even circuits and the network. The present study aims to review the findings of current research, discuss future directions of NIBS application, and finally promote the use of NIBS in post-stroke rehabilitation.
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Affiliation(s)
- Kun-Peng Li
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Jia-Jia Wu
- Center of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China
| | - Zong-Lei Zhou
- Department of Epidemiology, School of Public Health, Fudan University, Shanghai 200032, China
| | - Dong-Sheng Xu
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Mou-Xiong Zheng
- Department of Traumatology and Orthopedics, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China
- Correspondence: (M.-X.Z.); (X.-Y.H.); (J.-G.X.)
| | - Xu-Yun Hua
- Department of Traumatology and Orthopedics, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China
- Correspondence: (M.-X.Z.); (X.-Y.H.); (J.-G.X.)
| | - Jian-Guang Xu
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
- Engineering Research Center of Traditional Chinese Medicine Intelligent Rehabilitation, Ministry of Education, Shanghai 201203, China
- Correspondence: (M.-X.Z.); (X.-Y.H.); (J.-G.X.)
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22
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Abstract
The generation of an internal body model and its continuous update is essential in sensorimotor control. Although known to rely on proprioceptive sensory feedback, the underlying mechanism that transforms this sensory feedback into a dynamic body percept remains poorly understood. However, advances in the development of genetic tools for proprioceptive circuit elements, including the sensory receptors, are beginning to offer new and unprecedented leverage to dissect the central pathways responsible for proprioceptive encoding. Simultaneously, new data derived through emerging bionic neural machine-interface technologies reveal clues regarding the relative importance of kinesthetic sensory feedback and insights into the functional proprioceptive substrates that underlie natural motor behaviors.
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Affiliation(s)
- Paul D Marasco
- Laboratory for Bionic Integration, Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA;
- Charles Shor Epilepsy Center, Cleveland Clinic, Cleveland, Ohio, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Joriene C de Nooij
- Department of Neurology and the Columbia University Motor Neuron Center, Columbia University Medical Center, New York, NY, USA;
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23
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Turecek J, Lehnert BP, Ginty DD. The encoding of touch by somatotopically aligned dorsal column subdivisions. Nature 2022; 612:310-315. [PMID: 36418401 PMCID: PMC9729103 DOI: 10.1038/s41586-022-05470-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 10/20/2022] [Indexed: 11/25/2022]
Abstract
The somatosensory system decodes a range of tactile stimuli to generate a coherent sense of touch. Discriminative touch of the body depends on signals conveyed from peripheral mechanoreceptors to the brain through the spinal cord dorsal column and its brainstem target, the dorsal column nuclei (DCN)1,2. Models of somatosensation emphasize that fast-conducting low-threshold mechanoreceptors (LTMRs) innervating the skin drive the DCN3,4. However, postsynaptic dorsal column (PSDC) neurons within the spinal cord dorsal horn also collect mechanoreceptor signals and form a second major input to the DCN5-7. The significance of PSDC neurons and their contributions to the coding of touch have remained unclear since their discovery. Here we show that direct LTMR input to the DCN conveys vibrotactile stimuli with high temporal precision. Conversely, PSDC neurons primarily encode touch onset and the intensity of sustained contact into the high-force range. LTMR and PSDC signals topographically realign in the DCN to preserve precise spatial detail. Different DCN neuron subtypes have specialized responses that are generated by distinct combinations of LTMR and PSDC inputs. Thus, LTMR and PSDC subdivisions of the dorsal column encode different tactile features and differentially converge in the DCN to generate specific ascending sensory processing streams.
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Affiliation(s)
- Josef Turecek
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Brendan P Lehnert
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - David D Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA.
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24
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Santuz A, Laflamme OD, Akay T. The brain integrates proprioceptive information to ensure robust locomotion. J Physiol 2022; 600:5267-5294. [PMID: 36271747 DOI: 10.1113/jp283181] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 10/10/2022] [Indexed: 01/05/2023] Open
Abstract
Robust locomotion relies on information from proprioceptors: sensory organs that communicate the position of body parts to the spinal cord and brain. Proprioceptive circuits in the spinal cord are known to coarsely regulate locomotion in the presence of perturbations. Yet, the regulatory importance of the brain in maintaining robust locomotion remains less clear. Here, through mouse genetic studies and in vivo electrophysiology, we examined the role of the brain in integrating proprioceptive information during perturbed locomotion. The systemic removal of proprioceptors left the mice in a constantly perturbed state, similar to that observed during mechanically perturbed locomotion in wild-type mice and characterised by longer and less accurate synergistic activation patterns. By contrast, after surgically interrupting the ascending proprioceptive projection to the brain through the dorsal column of the spinal cord, wild-type mice showed normal walking behaviour, yet lost the ability to respond to external perturbations. Our findings provide direct evidence of a pivotal role for ascending proprioceptive information in achieving robust, safe locomotion. KEY POINTS: Whether brain integration of proprioceptive feedback is crucial for coping with perturbed locomotion is not clear. We showed a crucial role of the brain for responding to external perturbations and ensure robust locomotion. We used mouse genetics to remove proprioceptors and a spinal lesion model to interrupt the flow of proprioceptive information to the brain through the dorsal column in wild-type animals. Using a custom-built treadmill, we administered sudden and random mechanical perturbations to mice during walking. External perturbations affected locomotion in wild-type mice similar to the absence of proprioceptors in genetically modified mice. Proprioceptive feedback from muscle spindles and Golgi tendon organs contributed to locomotor robustness. Wild-type mice lost the ability to respond to external perturbations after interruption of the ascending proprioceptive projection to the brainstem.
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Affiliation(s)
- Alessandro Santuz
- Atlantic Mobility Action Project, Brain Repair Centre, Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Olivier D Laflamme
- Atlantic Mobility Action Project, Brain Repair Centre, Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Turgay Akay
- Atlantic Mobility Action Project, Brain Repair Centre, Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada
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25
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Sukumar V, Johansson RS, Pruszynski JA. Precise and stable edge orientation signaling by human first-order tactile neurons. eLife 2022; 11:e81476. [PMID: 36314774 PMCID: PMC9642991 DOI: 10.7554/elife.81476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 10/27/2022] [Indexed: 12/04/2022] Open
Abstract
Fast-adapting type 1 (FA-1) and slow-adapting type 1 (SA-1) first-order neurons in the human tactile system have distal axons that branch in the skin and form many transduction sites, yielding receptive fields with many highly sensitive zones or 'subfields.' We previously demonstrated that this arrangement allows FA-1 and SA-1 neurons to signal the geometric features of touched objects, specifically the orientation of raised edges scanned with the fingertips. Here, we show that such signaling operates for fine edge orientation differences (5-20°) and is stable across a broad range of scanning speeds (15-180 mm/s); that is, under conditions relevant for real-world hand use. We found that both FA-1 and SA-1 neurons weakly signal fine edge orientation differences via the intensity of their spiking responses and only when considering a single scanning speed. Both neuron types showed much stronger edge orientation signaling in the sequential structure of the evoked spike trains, and FA-1 neurons performed better than SA-1 neurons. Represented in the spatial domain, the sequential structure was strikingly invariant across scanning speeds, especially those naturally used in tactile spatial discrimination tasks. This speed invariance suggests that neurons' responses are structured via sequential stimulation of their subfields and thus links this capacity to their terminal organization in the skin. Indeed, the spatial precision of elicited action potentials rationally matched spatial acuity of subfield arrangements, which corresponds to a spatial period similar to the dimensions of individual fingertip ridges.
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26
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Molecular Organization and Patterning of the Medulla Oblongata in Health and Disease. Int J Mol Sci 2022; 23:ijms23169260. [PMID: 36012524 PMCID: PMC9409237 DOI: 10.3390/ijms23169260] [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: 06/29/2022] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 11/17/2022] Open
Abstract
The medulla oblongata, located in the hindbrain between the pons and the spinal cord, is an important relay center for critical sensory, proprioceptive, and motoric information. It is an evolutionarily highly conserved brain region, both structural and functional, and consists of a multitude of nuclei all involved in different aspects of basic but vital functions. Understanding the functional anatomy and developmental program of this structure can help elucidate potential role(s) of the medulla in neurological disorders. Here, we have described the early molecular patterning of the medulla during murine development, from the fundamental units that structure the very early medullary region into 5 rhombomeres (r7–r11) and 13 different longitudinal progenitor domains, to the neuronal clusters derived from these progenitors that ultimately make-up the different medullary nuclei. By doing so, we developed a schematic overview that can be used to predict the cell-fate of a progenitor group, or pinpoint the progenitor domain of origin of medullary nuclei. This schematic overview can further be used to help in the explanation of medulla-related symptoms of neurodevelopmental disorders, e.g., congenital central hypoventilation syndrome, Wold–Hirschhorn syndrome, Rett syndrome, and Pitt–Hopkins syndrome. Based on the genetic defects seen in these syndromes, we can use our model to predict which medullary nuclei might be affected, which can be used to quickly direct the research into these diseases to the likely affected nuclei.
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27
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Tozzi A. Bipolar reasoning in feedback pathways. Biosystems 2022; 215-216:104652. [PMID: 35247481 DOI: 10.1016/j.biosystems.2022.104652] [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: 01/13/2022] [Revised: 02/26/2022] [Accepted: 02/26/2022] [Indexed: 11/18/2022]
Abstract
Instead of the conventional 0 and 1 values, bipolar reasoning uses -1, 0, +1 to describe double-sided judgements in which neutral elements are halfway between positive and negative evaluations (e.g., "uncertain" lies between "impossible" and "totally sure"). We discuss the state-of-the-art in bipolar logics and recall two medieval forerunners, i.e., William of Ockham and Nicholas of Autrecourt, who embodied a bipolar mode of thought that is eminently modern. Starting from the trivial observation that "once a wheat sheaf is sealed and tied up, the packed down straws display the same orientation", we work up a new theory of the bipolar nature of networks, suggesting that orthodromic (i.e., feedforward, bottom-up) projections might be functionally coupled with antidromic (i.e., feedback, top-down) projections via the mathematical apparatus of presheaves/globular sets. When an entrained oscillation such as a neuronal spike propagates from A to B, changes in B might lead to changes in A, providing unexpected antidromic effects. Our account points towards the methodological feasibility of novel neural networks in which message feedback is guaranteed by backpropagation mechanisms endowed in the same feedforward circuits. Bottom-up/top-down transmission at various coarse-grained network levels provides fresh insights in far-flung scientific fields such as object persistence, memory reinforcement, visual recognition, Bayesian inferential circuits and multidimensional activity of the brain. Implying that axonal stimulation by external sources might backpropagate and modify neuronal electric oscillations, our theory also suggests testable previsions concerning the optimal location of transcranial magnetic stimulation's coils in patients affected by drug-resistant epilepsy.
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Affiliation(s)
- Arturo Tozzi
- Center for Nonlinear Science, Department of Physics, University of North Texas, Denton, TX, USA, 1155 Union Circle, #311427, Denton, TX, 76203-5017, USA.
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28
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Suresh AK, Greenspon CM, He Q, Rosenow JM, Miller LE, Bensmaia SJ. Sensory computations in the cuneate nucleus of macaques. Proc Natl Acad Sci U S A 2021; 118:e2115772118. [PMID: 34853173 PMCID: PMC8670430 DOI: 10.1073/pnas.2115772118] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 10/25/2021] [Indexed: 12/15/2022] Open
Abstract
Tactile nerve fibers fall into a few classes that can be readily distinguished based on their spatiotemporal response properties. Because nerve fibers reflect local skin deformations, they individually carry ambiguous signals about object features. In contrast, cortical neurons exhibit heterogeneous response properties that reflect computations applied to convergent input from multiple classes of afferents, which confer to them a selectivity for behaviorally relevant features of objects. The conventional view is that these complex response properties arise within the cortex itself, implying that sensory signals are not processed to any significant extent in the two intervening structures-the cuneate nucleus (CN) and the thalamus. To test this hypothesis, we recorded the responses evoked in the CN to a battery of stimuli that have been extensively used to characterize tactile coding in both the periphery and cortex, including skin indentations, vibrations, random dot patterns, and scanned edges. We found that CN responses are more similar to their cortical counterparts than they are to their inputs: CN neurons receive input from multiple classes of nerve fibers, they have spatially complex receptive fields, and they exhibit selectivity for object features. Contrary to consensus, then, the CN plays a key role in processing tactile information.
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Affiliation(s)
- Aneesha K Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL 60637
| | - Charles M Greenspon
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637
| | - Qinpu He
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL 60637
| | - Joshua M Rosenow
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Lee E Miller
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208
- Shirley Ryan AbilityLab, Chicago, IL 60611
| | - Sliman J Bensmaia
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL 60637;
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637
- Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL 60637
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29
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Judd EN, Lewis SM, Person AL. Diverse inhibitory projections from the cerebellar interposed nucleus. eLife 2021; 10:e66231. [PMID: 34542410 PMCID: PMC8483738 DOI: 10.7554/elife.66231] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 09/19/2021] [Indexed: 11/17/2022] Open
Abstract
The cerebellum consists of parallel circuit modules that contribute to diverse behaviors, spanning motor to cognitive. Recent work employing cell-type-specific tracing has identified circumscribed output channels of the cerebellar nuclei (CbN) that could confer tight functional specificity. These studies have largely focused on excitatory projections of the CbN, however, leaving open the question of whether inhibitory neurons also constitute multiple output modules. We mapped output and input patterns to intersectionally restricted cell types of the interposed and adjacent interstitial nuclei in mice. In contrast to the widespread assumption of primarily excitatory outputs and restricted inferior olive-targeting inhibitory output, we found that inhibitory neurons from this region ramified widely within the brainstem, targeting both motor- and sensory-related nuclei, distinct from excitatory output targets. Despite differences in output targeting, monosynaptic rabies tracing revealed largely shared afferents to both cell classes. We discuss the potential novel functional roles for inhibitory outputs in the context of cerebellar theory.
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Affiliation(s)
- Elena N Judd
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Anschutz Medical CampusAuroraUnited States
| | - Samantha M Lewis
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Anschutz Medical CampusAuroraUnited States
| | - Abigail L Person
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Anschutz Medical CampusAuroraUnited States
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