Maintaining grip: Anticipatory and reactive EEG responses to load perturbations


Kourtis D, Kwok HF, Roach N, Wing A & Praamstra P (2008) Maintaining grip: Anticipatory and reactive EEG responses to load perturbations. Journal of Neurophysiology, 99 (2), pp. 545-553.

Previous behavioral work has shown the existence of both anticipatory and reactive grip force responses to predictable load perturbations, but how the brain implements anticipatory control remains unclear. Here we recorded electroencephalographs while participants were subjected to predictable and unpredictable external load perturbations. Participants used precision grip to maintain the position of an object perturbed by load force pulses. The load perturbations were either distributed randomly over an interval 700- to 4,300-ms (unpredictable condition) or they were periodic with interval 2,000 ms (predictable condition). Preparation for the predictable load perturbation was manifested in slow preparatory brain potentials and in electromyographic and force signals recorded concurrently. Preparation modulated the long-latency reflex elicited by load perturbations with a higher amplitude reflex response for unpredictable compared with predictable perturbations. Importantly, this modulation was also reflected in the amplitude of sensorimotor cortex potentials just preceding the long-latency reflex. Together, these results support a transcortical pathway for the longlatency reflex and a central modulation of the reflex grip force response. Copyright © 2008 The American Physiological Society.

Journal of Neurophysiology: Volume 99, Issue 2

FundersMedical Research Council
Publication date01/02/2008
Publication date online01/02/2008
Date accepted by journal19/11/2007
PublisherAmerican Physiological Society