Emotional states alter force control during a feedback occluded motor task

The aim of the current experiment was to determine the extent to which pleasant and unpleasant emotional states altered the ability of men and women to control force production on a feedback occluded motor task that was not direction specific. Participants produced a precision pinch grip with visual feedback. After 5 s, feedback was occluded and replaced with a pleasant, unpleasant, or neutral image. The amplitude, variability, and structure of force production were calculated. As expected, the removal of visual feedback led to progressive force decay. More important, relative to neutral conditions, pleasant and unpleasant emotional states led to greater force production, resulting in attenuated force decay. The variability and structure of force production were not altered by affective state. In addition, men and women performed similarly across all conditions for all measures. We conclude that when sustained force production is not directed toward or away from the body, pleasant and unpleasant emotional states similarly excite the motor system. Neurobiological mechanisms are proposed to account for these findings. Implications and future research directions are discussed.