scholarly journals Paired-pulse TMS and scalp EEG reveal systematic relationship between inhibitory GABAa signaling in M1 and fronto-central cortical activity during action stopping

2021 ◽  
Vol 125 (2) ◽  
pp. 648-660
Author(s):  
Megan Hynd ◽  
Cheol Soh ◽  
Benjamin O. Rangel ◽  
Jan R. Wessel
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Neural Mechanisms ◽  
Central Control ◽  
Neural Signals ◽  
Scalp Eeg ◽  
Rapid Action ◽  
First Time ◽  
Inhibitory Motor Control ◽  
Intense Debate

The neural mechanisms underlying rapid action stopping in humans are subject to intense debate, in part because recordings of neural signals purportedly reflecting inhibitory motor control are hard to directly relate to the true, physiological inhibition of motor cortex. For the first time, the current study combines EEG and transcranial magnetic stimulation (TMS) methods to demonstrate a direct correspondence between fronto-central control-related EEG activity following signals to cancel an action and the physiological inhibition of primary motor cortex.

scholarly journals Functional Localization of an Attenuating Filter within Cortex for a Selective Detection Task in Mice

2020 ◽  
Author(s):  
Krithiga Aruljothi ◽  
Krista Marrero ◽  
Zhaoran Zhang ◽  
Behzad Zareian ◽  
Edward Zagha
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Selection Process ◽  
Detection Task ◽  
Neural Mechanisms ◽  
Selective Detection ◽  
Strong Signal ◽  
Distractor Processing ◽  
Goal Directed Behavior ◽  
Signal Activation

AbstractAn essential feature of goal-directed behavior is the ability to selectively respond to the diverse stimuli in one’s environment. However, the neural mechanisms that enable us to respond to target stimuli while ignoring distractor stimuli are poorly understood. To study this sensory selection process, we trained male and female mice in a selective detection task in which mice learn to respond to rapid stimuli in the target whisker field and ignore identical stimuli in the opposite, distractor whisker field. In expert mice, we used widefield Ca2+ imaging to analyze target-related and distractor-related neural responses throughout dorsal cortex. For target stimuli, we observed strong signal activation in primary somatosensory cortex (S1) and frontal cortices, including both the whisker representation of primary motor cortex (wMC) and anterior lateral motor cortex (ALM). For distractor stimuli, we observe strong signal activation in S1, with minimal propagation to frontal cortex. Our data support only modest subcortical filtering, with robust, step-like attenuation in distractor processing between mono-synaptically coupled regions of S1 and wMC. This study establishes a highly robust model system for studying the neural mechanisms of sensory selection and places important constraints on its implementation.SummaryResponding to task-relevant stimuli while ignoring task-irrelevant stimuli is critical for goal-directed behavior. Yet, the neural mechanisms involved in this selection process are poorly understood. We trained mice in a detection task with both target and distractor stimuli. During expert performance, we measured neural activity throughout cortex using widefield imaging. We observed responses to target stimuli in multiple sensory and motor cortical regions. In contrast, responses to distractor stimuli were abruptly suppressed beyond sensory cortex. Our findings localize the sites of attenuation when successfully ignoring a distractor stimulus, and provide essential foundations for further revealing the neural mechanism of sensory selection and distractor suppression.

scholarly journals Pre-movement changes in sensorimotor beta oscillations predict motor adaptation drive

2020 ◽  
Author(s):  
Henry T Darch ◽  
Nadia L Cerminara ◽  
Iain D Gilchrist ◽  
Richard Apps
Keyword(s):  
Reaction Time ◽  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Visuomotor Adaptation ◽  
Beta Oscillations ◽  
Scalp Eeg ◽  
Eeg Recordings ◽  
Beta Frequency ◽  
Late Adaptation ◽  
Adaptation Task

AbstractBeta frequency oscillations in scalp electroencephalography (EEG) recordings over the primary motor cortex have been associated with the preparation and execution of voluntary movements. Here, we test whether changes in beta frequency are related to the preparation of adapted movements in human, and whether such effects generalise to other species (cat). Eleven healthy adult humans performed a joystick visuomotor adaptation task. Beta (15-25Hz) scalp EEG signals recorded over the motor cortex during a pre-movement preparatory phase were, on average, significantly reduced in amplitude during early adaptation trials compared to baseline or late adaptation trials (p=0.01). The changes in beta were not related to measurements of reaction time or duration of the reach. We also recorded LFP activity within the primary motor cortex of three cats during a prism visuomotor adaptation task. Analysis of these signals revealed similar reductions in motor cortical LFP beta frequencies during early adaptation. This effect was also present when controlling for any influence of the reaction time and reaching duration. Overall, the results are consistent with a reduction in pre-movement beta oscillations predicting an increase in adaptive drive in upcoming task performance when motor errors are largest in magnitude and the rate of adaptation is greatest.

scholarly journals Representation of individual forelimb muscles in primary motor cortex

2017 ◽  
Vol 118 (1) ◽  
pp. 47-63 ◽  
Author(s):  
Heather M. Hudson ◽  
Michael C. Park ◽  
Abderraouf Belhaj-Saïf ◽  
Paul D. Cheney
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Emg Activity ◽  
Medial Branch ◽  
Precentral Gyrus ◽  
Body Parts ◽  
Reach To Grasp ◽  
Somatotopic Organization ◽  
Forelimb Muscles ◽  
First Time

Stimulus-triggered averaging (StTA) of forelimb muscle electromyographic (EMG) activity was used to investigate individual forelimb muscle representation within the primary motor cortex (M1) of rhesus macaques with the objective of determining the extent of intra-areal somatotopic organization. Two monkeys were trained to perform a reach-to-grasp task requiring multijoint coordination of the forelimb. EMG activity was simultaneously recorded from 24 forelimb muscles including 5 shoulder, 7 elbow, 5 wrist, 5 digit, and 2 intrinsic hand muscles. Microstimulation (15 µA at 15 Hz) was delivered throughout the movement task and individual stimuli were used as triggers for generating StTAs of EMG activity. StTAs were used to map the cortical representations of individual forelimb muscles. As reported previously (Park et al. 2001), cortical maps revealed a central core of distal muscle (wrist, digit, and intrinsic hand) representation surrounded by a horseshoe-shaped proximal (shoulder and elbow) muscle representation. In the present study, we found that shoulder and elbow flexor muscles were predominantly represented in the lateral branch of the horseshoe whereas extensors were predominantly represented in the medial branch. Distal muscles were represented within the core distal forelimb representation and showed extensive overlap. For the first time, we also show maps of inhibitory output from motor cortex, which follow many of the same organizational features as the maps of excitatory output. NEW & NOTEWORTHY While the orderly representation of major body parts along the precentral gyrus has been known for decades, questions have been raised about the possible existence of additional more detailed aspects of somatotopy. In this study, we have investigated this question with respect to muscles of the arm and show consistent features of within-arm (intra-areal) somatotopic organization. For the first time we also show maps of how inhibitory output from motor cortex is organized.

scholarly journals Neural Activity in Human Primary Motor Cortex Areas 4a and 4p Is Modulated Differentially by Attention to Action

2002 ◽  
Vol 88 (1) ◽  
pp. 514-519 ◽  
Author(s):  
F. Binkofski ◽  
G. R. Fink ◽  
S. Geyer ◽  
G. Buccino ◽  
O. Gruber ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Motor Cortex ◽  
Functional Magnetic Resonance Imaging ◽  
Neural Activity ◽  
Primary Motor Cortex ◽  
Direct Evidence ◽  
Neural Mechanisms ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

The mechanisms underlying attention to action are poorly understood. Although distracted by something else, we often maintain the accuracy of a movement, which suggests that differential neural mechanisms for the control of attended and nonattended action exist. Using functional magnetic resonance imaging (fMRI) in normal volunteers and probabilistic cytoarchitectonic maps, we observed that neural activity in subarea 4p (posterior) within the primary motor cortex was modulated by attention to action, while neural activity in subarea 4a (anterior) was not. The data provide the direct evidence for differential neural mechanisms during attended and unattended action in human primary motor cortex.

scholarly journals Motor cortex signals corresponding to the two arms are shared across hemispheres, mixed among neurons, yet partitioned within the population response

2019 ◽  
Author(s):  
K. Cora Ames ◽  
Mark M. Churchland
Keyword(s):  
Motor Cortex ◽  
Neural Activity ◽  
Muscle Activity ◽  
Primary Motor Cortex ◽  
Population Level ◽  
Response Patterns ◽  
Neural Signals ◽  
Population Activity ◽  
The Individual

AbstractPrimary motor cortex (M1) has lateralized outputs, yet M1 neurons can be active during movements of either arm. What is the nature and role of activity in the two hemispheres? When one arm moves, are the contralateral and ipsilateral cortices performing similar or different computations? When both hemispheres are active, how does the brain avoid moving the “wrong” arm? We recorded muscle and neural activity bilaterally while two male monkeys (Macaca mulatta) performed a cycling task with one or the other arm. Neurons in both hemispheres were active during movements of either arm. Yet response patterns were arm-dependent, raising two possibilities. First, the nature of neural signals may differ (e.g., be high versus low-level) depending on whether the ipsilateral or contralateral arm is used. Second, the same population-level signals may be present regardless of the arm being used, but be reflected differently at the individual-neuron level. The data supported this second hypothesis. Muscle activity could be predicted by neural activity in either hemisphere. More broadly, we failed to find signals unique to the hemisphere contralateral to the moving arm. Yet if the same signals are shared across hemispheres, how do they avoid impacting the wrong arm? We found that activity related to the two arms occupied distinct, orthogonal subspaces of population activity. As a consequence, a linear decode of contralateral muscle activity naturally ignored signals related to the ipsilateral arm. Thus, information regarding the two arms is shared across hemispheres and neurons, but partitioned at the population level.

scholarly journals Differentiation of cerebral representation of occlusion and swallowing with fMRI

2013 ◽  
Vol 304 (10) ◽  
pp. G847-G854 ◽  
Author(s):  
Paul G. Mihai ◽  
Oliver von Bohlen und Halbach ◽  
Martin Lotze
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Neural Representation ◽  
Motor Representation ◽  
Functional Representation ◽  
Fmri Study ◽  
Sensory Nucleus ◽  
Supplementary Motor Cortex ◽  
Movement Representation ◽  
First Time

Early work on representational specificity and recent findings on temporomandibular joint (TMJ) movement representation raise doubts that a specific swallow representation does exist. Additionally, during cortical stimulation TMJ movements and swallowing show a high overlap of representational areas in the primary motor cortex. It has thus been hypothesized that they overall might share the same neural structures. To differentiate these two movements, we performed a functional MRI (fMRI) study that enabled a direct comparison of functional representation of both actions in the same subject group. Effort during these tasks was controlled by skin conductance response. When balancing effort, we found a comparable neural representation pattern for both tasks but increased resources necessary to perform swallowing in direct comparison between tasks. For the first time, with the usage of fMRI, we demonstrated a representation in the brainstem for swallowing and occlusion. Increased activation for swallowing was observed in bilateral sensorimotor cortex, bilateral premotor and supplementary motor cortex, motor cingulate, thalamus, cerebellar hemispheres, left pallidum, bilateral pons, and midbrain. Peaks of activation in primary motor cortex between both conditions were about 5 mm adjacent. Brainstem activation was found corresponding to the sensory nucleus of the trigeminal nerve, the solitary nucleus for swallowing, and the trigeminal nucleus for occlusion. Our data suggest that cerebral representation of occlusion and swallowing are spatially widely overlapping, differing predominantly with respect to the quantity of neural resources involved. Both brainstem and primary motor representation differ in location with respect to somatotopy and contribution of cranial nerve nuclei.

scholarly journals Motor imagery practice during arm-immobilization benefits sensorimotor cortical functions and plasticity-related sleep features

2019 ◽  
Author(s):  
Ursula Debarnot ◽  
Aurore. A. Perrault ◽  
Virginie Sterpenich ◽  
Guillaume Legendre ◽  
Chieko Huber ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Motor Imagery ◽  
Rem Sleep ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Neural Mechanisms ◽  
Sleep Spindles ◽  
Cortical Representations ◽  
Cortical Functions

ABSTRACTMotor imagery (MI) is known to engage motor networks and could compensate for the maladaptive neuroplasticity elicited by immobilization. This hypothesis and associated underlying neural mechanisms remain underexplored. Here, we investigated how MI practice during 11 h of arm-immobilization influences sensorimotor and cortical representations of the hands, as well as sleep. Fourteen participants were first tested after a normal day, followed by two 11-h periods of immobilization, either with concomitant MI treatment or control tasks. Data revealed that MI prevented the consequences of immobilization: (i) alteration of the sensorimotor representation of hands, (ii) decrease of cortical excitability over the primary motor cortex (M1) contralateral to arm-immobilization, and (iii) reduction of sleep spindles over both M1s. Furthermore, (iv) the time spent in REM sleep was significantly longer after MI. These results support that implementing MI during immobilization can limit the deleterious effects of limb disuse, at several levels of sensorimotor functioning.

scholarly journals Pre-movement changes in sensorimotor beta oscillations predict motor adaptation drive

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Henry T. Darch ◽  
Nadia L. Cerminara ◽  
Iain D. Gilchrist ◽  
Richard Apps
Keyword(s):  
Reaction Time ◽  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Field Potential ◽  
Visuomotor Adaptation ◽  
Beta Oscillations ◽  
Scalp Eeg ◽  
Eeg Recordings ◽  
Beta Frequency ◽  
Adaptation Task

Abstract Beta frequency oscillations in scalp electroencephalography (EEG) recordings over the primary motor cortex have been associated with the preparation and execution of voluntary movements. Here, we test whether changes in beta frequency are related to the preparation of adapted movements in human, and whether such effects generalise to other species (cat). Eleven healthy adult humans performed a joystick visuomotor adaptation task. Beta (15–25 Hz) scalp EEG signals recorded over the motor cortex during a pre-movement preparatory phase were, on average, significantly reduced in amplitude during early adaptation trials compared to baseline, late adaptation, or aftereffect trials. The changes in beta were not related to measurements of reaction time or reach duration. We also recorded local field potential (LFP) activity within the primary motor cortex of three cats during a prism visuomotor adaptation task. Analysis of these signals revealed similar reductions in motor cortical LFP beta frequencies during early adaptation. This effect was present when controlling for any influence of the reaction time and reach duration. Overall, the results are consistent with a reduction in pre-movement beta oscillations predicting an increase in adaptive drive in upcoming task performance when motor errors are largest in magnitude and the rate of adaptation is greatest.

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