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document
Functional modification of agonist-antagonist electromyographic activity for rapid movement inhibition . Subjects made a fast elbow extension movement to designated target in response to a go signal . In 45 % of trials a stop signal was presented after the go signal , to which subjects were asked to stop the movement as rapidly as possible . The interstimulus interval ( ISI ) , or time interval between the go and stop signals , was randomly varied between 0 and 200 ms. Electromyographic ( EMG ) activity was recorded from biceps brachii and triceps brachii . Subjects could sometimes completely inhibit initiation of the movements when the ISI was 0 ms , but could rarely do so when the ISI exceeded 100 ms. For responses that were initiated but stopped on the way , the amplitude of the movement decreased linearly as the time interval ( =modification time ) from the stop signal to EMG onset increased . The peak velocity increased linearly as the movement amplitude increased . This tendency was similar to those previously reported in step-tracking movements with various amplitudes . In spite of the similarity in the kinematics of the movement , the EMG pattern was different from that of step-tracking movement . While the initial agonist burst ( AG1 ) decreased linearly after the modification time exceeded 100 ms , the antagonist burst ( ANT ) increased compared with the go trial for the modification time from 0 to 200 ms and decreased after the modification time exceeded 300 ms . This change of activation is analogous to functional modification of middle-latency reflex EMG response to load , or cutaneous perturbation . In conclusion , it is suggested that adaptive mechanisms , which would functionally modify the reflex responses , are also continuously working during voluntary movements in response to sudden changes in environmental information .
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Intervention_Physical
go signal
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Intervention_Physical
interstimulus interval ( ISI )
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Intervention_Physical
time interval between the go and stop signals
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Intervention_Physical
Electromyographic ( EMG )
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Outcome_Other
Electromyographic ( EMG ) activity
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Outcome_Other
amplitude of the movement
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Outcome_Other
peak velocity
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Outcome_Other
EMG pattern
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Outcome_Other
step-tracking movement
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Outcome_Physical
initial agonist burst ( AG1 )
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Outcome_Physical
antagonist burst ( ANT )
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Outcome_Other
EMG response
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Participant_Condition
modification of agonist-antagonist electromyographic activity for rapid movement inhibition
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Participant_Condition
Subjects made a fast elbow extension movement to designated target in response to a go signal