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Sadeghi M, Sharif Razavian R, Bazzi S, Chowdhury RH, Batista AP, Loughlin PJ, Sternad D. Inferring control objectives in a virtual balancing task in humans and monkeys. eLife 2024; 12:RP88514. [PMID: 38738986 PMCID: PMC11090506 DOI: 10.7554/elife.88514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024] Open
Abstract
Natural behaviors have redundancy, which implies that humans and animals can achieve their goals with different strategies. Given only observations of behavior, is it possible to infer the control objective that the subject is employing? This challenge is particularly acute in animal behavior because we cannot ask or instruct the subject to use a particular strategy. This study presents a three-pronged approach to infer an animal's control objective from behavior. First, both humans and monkeys performed a virtual balancing task for which different control strategies could be utilized. Under matched experimental conditions, corresponding behaviors were observed in humans and monkeys. Second, a generative model was developed that represented two main control objectives to achieve the task goal. Model simulations were used to identify aspects of behavior that could distinguish which control objective was being used. Third, these behavioral signatures allowed us to infer the control objective used by human subjects who had been instructed to use one control objective or the other. Based on this validation, we could then infer objectives from animal subjects. Being able to positively identify a subject's control objective from observed behavior can provide a powerful tool to neurophysiologists as they seek the neural mechanisms of sensorimotor coordination.
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Affiliation(s)
- Mohsen Sadeghi
- Department of Biology, Northeastern UniversityBostonUnited States
| | - Reza Sharif Razavian
- Department of Biology, Northeastern UniversityBostonUnited States
- Department of Electrical and Computer Engineering, Northeastern UniversityBostonUnited States
- Department of Mechanical Engineering, Northern Arizona UniversityFlagstaffUnited States
| | - Salah Bazzi
- Department of Biology, Northeastern UniversityBostonUnited States
- Department of Electrical and Computer Engineering, Northeastern UniversityBostonUnited States
- Institute for Experiential Robotics, Northeastern UniversityBostonUnited States
| | - Raeed H Chowdhury
- Department of Bioengineering, and Center for the Neural Basis of Cognition, University of PittsburghPittsburghUnited States
| | - Aaron P Batista
- Department of Bioengineering, and Center for the Neural Basis of Cognition, University of PittsburghPittsburghUnited States
| | - Patrick J Loughlin
- Department of Bioengineering, and Center for the Neural Basis of Cognition, University of PittsburghPittsburghUnited States
| | - Dagmar Sternad
- Department of Biology, Northeastern UniversityBostonUnited States
- Department of Electrical and Computer Engineering, Northeastern UniversityBostonUnited States
- Institute for Experiential Robotics, Northeastern UniversityBostonUnited States
- Department of Physics, Northeastern UniversityBostonUnited States
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2
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Dekleva BM, Chowdhury RH, Batista AP, Chase SM, Yu BM, Boninger ML, Collinger JL. Motor cortex retains and reorients neural dynamics during motor imagery. Nat Hum Behav 2024; 8:729-742. [PMID: 38287177 PMCID: PMC11089477 DOI: 10.1038/s41562-023-01804-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 12/13/2023] [Indexed: 01/31/2024]
Abstract
The most prominent characteristic of motor cortex is its activation during movement execution, but it is also active when we simply imagine movements in the absence of actual motor output. Despite decades of behavioural and imaging studies, it is unknown how the specific activity patterns and temporal dynamics in motor cortex during covert motor imagery relate to those during motor execution. Here we recorded intracortical activity from the motor cortex of two people who retain some residual wrist function following incomplete spinal cord injury as they performed both actual and imagined isometric wrist extensions. We found that we could decompose the population activity into three orthogonal subspaces, where one was similarly active during both action and imagery, and the others were active only during a single task type-action or imagery. Although they inhabited orthogonal neural dimensions, the action-unique and imagery-unique subspaces contained a strikingly similar set of dynamic features. Our results suggest that during motor imagery, motor cortex maintains the same overall population dynamics as during execution by reorienting the components related to motor output and/or feedback into a unique, output-null imagery subspace.
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Affiliation(s)
- Brian M Dekleva
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Raeed H Chowdhury
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Aaron P Batista
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Steven M Chase
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Byron M Yu
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Michael L Boninger
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jennifer L Collinger
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
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3
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Dekleva BM, Chowdhury RH, Batista AP, Chase SM, Yu BM, Boninger ML, Collinger JL. Motor cortex retains and reorients neural dynamics during motor imagery. bioRxiv 2023:2023.01.17.524394. [PMID: 36711675 PMCID: PMC9882181 DOI: 10.1101/2023.01.17.524394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The most prominent role of motor cortex is generating patterns of neural activity that lead to movement, but it is also active when we simply imagine movements in the absence of actual motor output. Despite decades of behavioral and imaging studies, it is unknown how the specific activity patterns and temporal dynamics within motor cortex during covert motor imagery relate to those during motor execution. Here we recorded intracortical activity from the motor cortex of two people with residual wrist function following incomplete spinal cord injury as they performed both actual and imagined isometric wrist extensions. We found that we could decompose the population-level activity into orthogonal subspaces such that one set of components was similarly active during both action and imagery, and others were only active during a single task typeâ€"action or imagery. Although they inhabited orthogonal neural dimensions, the action-unique and imagery-unique subspaces contained a strikingly similar set of dynamical features. Our results suggest that during motor imagery, motor cortex maintains the same overall population dynamics as during execution by recreating the missing components related to motor output and/or feedback within a unique imagery-only subspace.
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4
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Keshtkaran MR, Sedler AR, Chowdhury RH, Tandon R, Basrai D, Nguyen SL, Sohn H, Jazayeri M, Miller LE, Pandarinath C. A large-scale neural network training framework for generalized estimation of single-trial population dynamics. Nat Methods 2022; 19:1572-1577. [PMID: 36443486 PMCID: PMC9825111 DOI: 10.1038/s41592-022-01675-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 10/14/2022] [Indexed: 11/30/2022]
Abstract
Achieving state-of-the-art performance with deep neural population dynamics models requires extensive hyperparameter tuning for each dataset. AutoLFADS is a model-tuning framework that automatically produces high-performing autoencoding models on data from a variety of brain areas and tasks, without behavioral or task information. We demonstrate its broad applicability on several rhesus macaque datasets: from motor cortex during free-paced reaching, somatosensory cortex during reaching with perturbations, and dorsomedial frontal cortex during a cognitive timing task.
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Affiliation(s)
- Mohammad Reza Keshtkaran
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA
| | - Andrew R Sedler
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA
- Center for Machine Learning, Georgia Institute of Technology, Atlanta, GA, USA
| | - Raeed H Chowdhury
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Raghav Tandon
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA
- Center for Machine Learning, Georgia Institute of Technology, Atlanta, GA, USA
| | - Diya Basrai
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA
- Physiology and Neuroscience, University of California, San Diego, La Jolla, CA, USA
| | - Sarah L Nguyen
- College of Computing, Georgia Institute of Technology, Atlanta, GA, USA
| | - Hansem Sohn
- Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mehrdad Jazayeri
- Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Lee E Miller
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
- Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL, USA
- Shirley Ryan AbilityLab, Chicago, IL, USA
| | - Chethan Pandarinath
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA.
- Center for Machine Learning, Georgia Institute of Technology, Atlanta, GA, USA.
- Department of Neurosurgery, Emory University, Atlanta, GA, USA.
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5
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Gallego-Carracedo C, Perich MG, Chowdhury RH, Miller LE, Gallego JÁ. Local field potentials reflect cortical population dynamics in a region-specific and frequency-dependent manner. eLife 2022; 11:73155. [PMID: 35968845 PMCID: PMC9470163 DOI: 10.7554/elife.73155] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 08/02/2022] [Indexed: 11/13/2022] Open
Abstract
The spiking activity of populations of cortical neurons is well described by the dynamics of a small number of population-wide covariance patterns, the 'latent dynamics'. These latent dynamics are largely driven by the same correlated synaptic currents across the circuit that determine the generation of local field potentials (LFP). Yet, the relationship between latent dynamics and LFPs remains largely unexplored. Here, we characterised this relationship for three different regions of primate sensorimotor cortex during reaching. The correlation between latent dynamics and LFPs was frequency-dependent and varied across regions. However, for any given region, this relationship remained stable throughout the behaviour: in each of primary motor and premotor cortices, the LFP-latent dynamics correlation profile was remarkably similar between movement planning and execution. These robust associations between LFPs and neural population latent dynamics help bridge the wealth of studies reporting neural correlates of behaviour using either type of recordings.
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Affiliation(s)
| | - Matthew G Perich
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Raeed H Chowdhury
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, United States
| | - Lee E Miller
- Department of Biomedical Engineering, Northwestern University, Evanston, United States
| | - Juan Álvaro Gallego
- Department of Bioengineering, Imperial College London, London, United Kingdom
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6
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Abstract
Much remains unknown about the transformation of proprioceptive afferent input from the periphery to the cortex. Until recently, the only recordings from neurons in the cuneate nucleus (CN) were from anesthetized animals. We are beginning to learn more about how the sense of proprioception is transformed as it propagates centrally. Recent recordings from microelectrode arrays chronically implanted in CN have revealed that CN neurons with muscle-like properties have a greater sensitivity to active reaching movements than to passive limb displacement, and we find that these neurons have receptive fields that resemble single muscles. In this review, we focus on the varied uses of proprioceptive input and the possible role of CN in processing this information.
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Affiliation(s)
- Christopher Versteeg
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern 7 University, Evanston, IL, USA
| | - Raeed H Chowdhury
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, 10 Pittsburgh, PA, USA
| | - Lee E Miller
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern 7 University, Evanston, IL, USA.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, 13 IL, USA.,Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, 16 Northwestern University, Chicago, IL, USA.,Shirley Ryan AbilityLab, Chicago, IL, USA
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7
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Chowdhury RH, Hasan MN. Pembrolizumab Induced Hypophysitis in a Patient Allergic to Triamcinolone: An Increasingly Recognized Endocrinopathy Related to Immunotherapy. Mymensingh Med J 2020; 29:1021-1025. [PMID: 33116112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We would like to describe the clinical course of a 61-year-old gentleman with the background history of Stage IV left lower lobe lung adenocarcinoma who presented to the outpatient department at Changi General Hospital, Singapore on March 2019 with unintentional loss of weight, easy fatigability and breast pain while showering for last four months. He was started on pembrolizumab immunotherapy about 9 months before presentation which he tolerated well. Subsequent endocrine work ups revealed features consistent with hypophysitis that lead to hypopituitarism in the form of secondary adrenal insufficiency and hypothyroidism. While more and more patients are receiving novel anti-cancer treatment for example immunotherapy, we should never forget and address the side effects it brings along. This study certainly supports above mentioned suggestion.
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Affiliation(s)
- R H Chowdhury
- Dr Rezaul Haider Chowdhury, Resident Physician, Department of General Medicine, Changi General Hospital, Singapore
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8
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Gallego JA, Perich MG, Chowdhury RH, Solla SA, Miller LE. Long-term stability of cortical population dynamics underlying consistent behavior. Nat Neurosci 2020; 23:260-270. [PMID: 31907438 PMCID: PMC7007364 DOI: 10.1038/s41593-019-0555-4] [Citation(s) in RCA: 129] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 11/11/2019] [Indexed: 01/08/2023]
Abstract
Animals readily execute learned behaviors in a consistent manner over long periods of time, and yet no equally stable neural correlate has been demonstrated. How does the cortex achieve this stable control? Using the sensorimotor system as a model of cortical processing, we investigated the hypothesis that the dynamics of neural latent activity, which captures the dominant co-variation patterns within the neural population, must be preserved across time. We recorded from populations of neurons in premotor, primary motor and somatosensory cortices as monkeys performed a reaching task, for up to 2 years. Intriguingly, despite a steady turnover in the recorded neurons, the low-dimensional latent dynamics remained stable. The stability allowed reliable decoding of behavioral features for the entire timespan, while fixed decoders based directly on the recorded neural activity degraded substantially. We posit that stable latent cortical dynamics within the manifold are the fundamental building blocks underlying consistent behavioral execution.
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Affiliation(s)
- Juan A Gallego
- Neural and Cognitive Engineering Group, Center for Automation and Robotics, Spanish National Research Council, Arganda del Rey, Spain.
- Department of Physiology, Northwestern University, Chicago, IL, USA.
- Department of Bioengineering, Imperial College London, London, UK.
| | - Matthew G Perich
- Department of Fundamental Neuroscience, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Raeed H Chowdhury
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Sara A Solla
- Department of Physiology, Northwestern University, Chicago, IL, USA
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, USA
| | - Lee E Miller
- Department of Physiology, Northwestern University, Chicago, IL, USA.
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
- Department of Physical Medicine and Rehabilitation, Northwestern University, and Shirley Ryan Ability Lab, Chicago, IL, USA.
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9
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Abstract
Proprioception, the sense of body position, movement, and associated forces, remains poorly understood, despite its critical role in movement. Most studies of area 2, a proprioceptive area of somatosensory cortex, have simply compared neurons' activities to the movement of the hand through space. Using motion tracking, we sought to elaborate this relationship by characterizing how area 2 activity relates to whole arm movements. We found that a whole-arm model, unlike classic models, successfully predicted how features of neural activity changed as monkeys reached to targets in two workspaces. However, when we then evaluated this whole-arm model across active and passive movements, we found that many neurons did not consistently represent the whole arm over both conditions. These results suggest that 1) neural activity in area 2 includes representation of the whole arm during reaching and 2) many of these neurons represented limb state differently during active and passive movements.
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Affiliation(s)
- Raeed H Chowdhury
- Department of Biomedical EngineeringNorthwestern UniversityEvanstonUnited States
- Systems Neuroscience InstituteUniversity of PittsburghPittsburghUnited States
| | - Joshua I Glaser
- Interdepartmental Neuroscience ProgramNorthwestern UniversityChicagoUnited States
- Department of StatisticsColumbia UniversityNew YorkUnited States
- Zuckerman Mind Brain Behavior InstituteColumbia UniversityNew YorkUnited States
| | - Lee E Miller
- Department of Biomedical EngineeringNorthwestern UniversityEvanstonUnited States
- Department of PhysiologyNorthwestern UniversityChicagoUnited States
- Department of Physical Medicine and RehabilitationNorthwestern UniversityChicagoUnited States
- Shirley Ryan AbilityLabChicagoUnited States
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10
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Chowdhury RH, Ahmed SM, Hasan MN. Dengue Myocarditis: An Important Clinical Entity to Consider in Dengue Patient. Mymensingh Med J 2019; 28:708-711. [PMID: 31391450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We are going to report a case study of dengue fever (DF) affecting myocardium and explore the literature. A gentleman of 28 years old experienced DF which was complicated by acute myocarditis, acute kidney injury and hepatitis in the Emergency Department of Apollo Hospitals, Dhaka, Bangladesh on 5th August 2017. Clinically it was considered as an acute coronary syndrome due to depressed ST segment in chest leads ECG, extreme bradycardia but normal serum troponin-I level. He had to undergo temporary pacemaker insertion for symptomatic bradycardia and later on, he was monitored closely. Fortunately, he recovered; pacemaker was removed on day 8 of his admission without any further complication. After 3 days, patient recovered with symptomatic treatment. In different publications, various manifestations of cardiac complications occurred, from self-limiting tachy-brady arrhythmia to severe damage of the myocardium, causing reduced blood pressure and pulmonary edema. To reduce morbidity and mortality, physicians should suspect for cardiac complications in patients with dengue fever and should manage these complications.
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Affiliation(s)
- R H Chowdhury
- Dr Rezaul Haider Chowdhury, Resident Physician, Department of General Medicine, Changi General Hospital, Singapore
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11
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Mazurek KA, Berger M, Bollu T, Chowdhury RH, Elangovan N, Kuling IA, Sohn MH. Highlights from the 28th Annual Meeting of the Society for the Neural Control of Movement. J Neurophysiol 2018; 120:1671-1679. [PMID: 30020841 PMCID: PMC6230782 DOI: 10.1152/jn.00475.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 07/15/2018] [Indexed: 01/04/2023] Open
Affiliation(s)
- Kevin A Mazurek
- Department of Neuroscience, University of Rochester , Rochester, New York
- Del Monte Institute for Neuroscience, University of Rochester , Rochester, New York
| | - Michael Berger
- Cognitive Neuroscience Laboratory, German Primate Center-Leibniz-Institute for Primate Research, Göttingen , Germany
- Faculty of Biology and Psychology, University of Göttingen , Göttingen , Germany
| | - Tejapratap Bollu
- Department of Neurobiology and Behavior, Cornell University , Ithaca, New York
| | - Raeed H Chowdhury
- Department of Biomedical Engineering, Northwestern University , Evanston, Illinois
- Department of Physiology, Northwestern University , Chicago, Illinois
| | - Naveen Elangovan
- Human Sensorimotor Control Lab, University of Minnesota , Minneapolis, Minnesota
| | - Irene A Kuling
- Department of Human Movement Sciences, VU University , Amsterdam , The Netherlands
| | - M Hongchul Sohn
- Department of Biomedical Engineering, Northwestern University , Evanston, Illinois
- Shirley Ryan AbilityLab, Chicago, Illinois
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12
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Benjamin AS, Fernandes HL, Tomlinson T, Ramkumar P, VerSteeg C, Chowdhury RH, Miller LE, Kording KP. Modern Machine Learning as a Benchmark for Fitting Neural Responses. Front Comput Neurosci 2018; 12:56. [PMID: 30072887 PMCID: PMC6060269 DOI: 10.3389/fncom.2018.00056] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 06/29/2018] [Indexed: 11/13/2022] Open
Abstract
Neuroscience has long focused on finding encoding models that effectively ask "what predicts neural spiking?" and generalized linear models (GLMs) are a typical approach. It is often unknown how much of explainable neural activity is captured, or missed, when fitting a model. Here we compared the predictive performance of simple models to three leading machine learning methods: feedforward neural networks, gradient boosted trees (using XGBoost), and stacked ensembles that combine the predictions of several methods. We predicted spike counts in macaque motor (M1) and somatosensory (S1) cortices from standard representations of reaching kinematics, and in rat hippocampal cells from open field location and orientation. Of these methods, XGBoost and the ensemble consistently produced more accurate spike rate predictions and were less sensitive to the preprocessing of features. These methods can thus be applied quickly to detect if feature sets relate to neural activity in a manner not captured by simpler methods. Encoding models built with a machine learning approach accurately predict spike rates and can offer meaningful benchmarks for simpler models.
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Affiliation(s)
- Ari S. Benjamin
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Hugo L. Fernandes
- Department of Physical Medicine and Rehabilitation, Rehabilitation Institute of Chicago, Northwestern University, Chicago, IL, United States
| | - Tucker Tomlinson
- Department of Physiology, Northwestern University, Chicago, IL, United States
| | - Pavan Ramkumar
- Department of Physical Medicine and Rehabilitation, Rehabilitation Institute of Chicago, Northwestern University, Chicago, IL, United States
- Department of Neurobiology, Northwestern University, Evanston, IL, United States
| | - Chris VerSteeg
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States
| | - Raeed H. Chowdhury
- Department of Physiology, Northwestern University, Chicago, IL, United States
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States
| | - Lee E. Miller
- Department of Physical Medicine and Rehabilitation, Rehabilitation Institute of Chicago, Northwestern University, Chicago, IL, United States
- Department of Physiology, Northwestern University, Chicago, IL, United States
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States
| | - Konrad P. Kording
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, United States
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13
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Chowdhury RH, Tresch MC, Miller LE. Musculoskeletal geometry accounts for apparent extrinsic representation of paw position in dorsal spinocerebellar tract. J Neurophysiol 2017; 118:234-242. [PMID: 28381486 DOI: 10.1152/jn.00695.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 03/31/2017] [Accepted: 03/31/2017] [Indexed: 11/22/2022] Open
Abstract
Proprioception, the sense of limb position and motion, arises from individual muscle receptors. An important question is how and where in the neuroaxis our high level "extrinsic" sense of limb movement originates. In the 1990s, a series of papers detailed the properties of neurons in the dorsal spinocerebellar tract (DSCT) of the cat. Despite their direct projections from sensory receptors, it appeared that half of these neurons had consistent, high-level tuning to paw position rather than to joint angles (or muscle lengths). These results suggested that many DSCT neurons compute paw position from lower level sensory information. We examined the contribution of musculoskeletal geometry to this apparent extrinsic representation by simulating a three-joint hindlimb with mono- and biarticular muscles, each providing a muscle spindlelike signal, modulated by the muscle length. We simulated neurons driven by randomly weighted combinations of these signals and moved the paw to different positions under two joint-covariance conditions similar to the original experiments. Our results paralleled those experiments in a number of respects: 1) Many neurons were tuned to paw position relative to the hip under both conditions. 2) The distribution of tuning was strongly bimodal, with most neurons driven by whole-leg flexion or extension. 3) The change in tuning between conditions clustered around zero (median absolute change ~20°). These results indicate that, at least for these constraint conditions, extrinsic-like representation can be achieved simply through musculoskeletal geometry and convergent muscle length inputs. Consequently, they suggest a reinterpretation of the earlier results may be required.NEW & NOTEWORTHY A classic experiment concluding that many dorsal spinocerebellar tract neurons encode paw position rather than joint angles has been cited by many studies as evidence for high-level computation occurring within a single synapse of the sensors. However, our study provides evidence that such a computation is not required to explain the results. Using simulation, we replicated many of the original results with purely random connectivity, suggesting that a reinterpretation of the classic experiment is needed.
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Affiliation(s)
- Raeed H Chowdhury
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois
| | - Matthew C Tresch
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois.,Department of Physiology, Northwestern University, Chicago, Illinois.,Department of Physical Medicine and Rehabilitation, Northwestern University and Rehabilitation Institute of Chicago, Chicago, Illinois; and.,Shirley Ryan AbilityLab, Chicago, Illinois
| | - Lee E Miller
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois; .,Department of Physiology, Northwestern University, Chicago, Illinois.,Department of Physical Medicine and Rehabilitation, Northwestern University and Rehabilitation Institute of Chicago, Chicago, Illinois; and.,Shirley Ryan AbilityLab, Chicago, Illinois
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14
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Uddin MS, Hoque MI, Uddin MK, Kamol SA, Chowdhury RH. Circadian rhythm of onset of stroke - in 50 cases of ischemic stroke. Mymensingh Med J 2015; 24:121-126. [PMID: 25725678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Stroke is a leading cause of death and disability worldwide. While the immediate consequence of stroke include permanent cognitive deficits, paralysis, visual impairment and sensory disturbances; stroke also results in long term dysregulation of sleep and mood, which may be equally disabling. The influence of ischemic stroke on circadian rhythm regulation, which is strongly linked to sleep and mood, may thus potentially influence long term recovery in stroke patients. Stroke induces immediate changes in the timing of pineal melatonin secretion, indicating that cortical and basal ganglia infarction impacts the timing of melatonin rhythms. This study was done to find out the time of onset of most of the ischemic stroke attack and to determine the outcome of ischemic stroke during hospital stay. All ischemic stroke patients admitted in Medicine wards in Comilla Medical College Hospital during the period of 1st November 2010 to 30th April 2011 included in this study. After admission, a careful history and a thorough clinical examination was carried out. Data collection was done on a preset questionnaire which involved to identify the risk factors, the time of onset of ischemic stroke, and outcome during hospital stay. All the cases were investigated. Among the 50 ischemic stroke patients, 68% were male and 32% female. Maximum age groups were 61-70 years (50%). By occupational category, maximum were retired persons (46%); 68% were hypertensive, 38% smoker and 16% had diabetes. Dyslipidemia was present in 44% patients. Most of the ischemic stroke (44%) occurred in the morning to late morning (6:01AM-12:00PM) and majority (80%) of the patients was discharged with residual neurological dysfunction. This study supports the presence of a circadian pattern in the onset of ischemic stroke, with higher risk in the morning to late morning. Most of the patients were discharged with residual neurological dysfunction.
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Affiliation(s)
- M S Uddin
- Professor Md Shahab Uddin, Professor and Head, Department of Medicine, Comilla Medical College Hospital, Comilla, Bangladesh
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