Maintaining grip: anticipatory and reactive EEG responses to load perturbations

Dimtrios Kourtis, Hoi Kwok, Nick Roach, Alan Wing, Peter Praamstra

Research output: Contribution to journalArticle

19 Citations (Scopus)


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 long-latency reflex and a central modulation of the reflex grip force response.
Original languageEnglish
Pages (from-to)545-53
Number of pages9
JournalJournal of Neurophysiology
Issue number2
Publication statusPublished - 1 Feb 2008


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