Intermuscular coherence (IMC) reveals that affective emotional pictures modulate neural control mechanisms during the initiation of arm pointing movements.

Abstract

Several studies in psychology suggest that relationships exist between emotional context and motor control. Such a claim is based mainly on behavioral investigations whereas the underlying neurophysiological processes remain little known. Using a classical paradigm in motor control, we tested the impacts of viewing standardized affective pictures during pointing movements performed from a standing position. The hand reaction and movement times were measured and ten muscle activities spread around the body were recorded to investigate the intermuscular coherence between muscle pairs of interest. The hand movement time increased when an emotional picture perceived as unpleasant appeared under the target to reach, compared to an emotional picture perceived as pleasant. When an unpleasant emotional picture appeared, the beta (β, 15-35 Hz) and gamma (γ, 35-60 Hz) intermuscular coherence decreased in the recorded pairs of postural muscles during the initiation of pointing movements. Moreover, a linear relationship between the magnitude of the intermuscular coherence in the pairs of posturo-focal muscles and the hand movement time appeared in the unpleasant scenarios. Our findings demonstrate that emotional stimuli induce modulation of the motor command sent by the central nervous system to muscles when performing voluntary goal-oriented movements.