Anticipatory postural control associated with bilateral arm flexion and event-related potential in a Kanji...

We investigated anticipatory postural control during arm flexion and event-related potential (ERP) in a Kanji Stroop-like task.

The Kanji for RED or BLUE colored in red, blue, or black was randomly presented on a screen for 100 ms. Subjects flexed their arms in response to target stimuli colored black (control condition) or which were congruent or incongruent with the meaning of Kanji characters. P300 of ERPs elicited by the target stimuli and onset timing of electromyographic activity in arm and postural muscles were measured.

Reaction time of the anterior deltoid (AD) was shorter and P300 amplitude larger in the order of control, congruent, and incongruent conditions. A distinct P515 component was recognized in ERPs under congruent and incongruent conditions. No significant difference among conditions was observed in onset timing of erector spinae, biceps femoris, or gastrocnemius activity with respect to AD.

Changes in cognitive processing and allocation of attentional resources according to task demands influence the onset timing of arm movement, but not that of anticipatory postural control, suggesting the presence of fixed synergy of arm movement and postural control.

These findings are important for understanding the effects of cognitive function on anticipatory postural control.