Does slippage influence the EEG response to load force variations during object manipulation?

Abstract

During object manipulation, sensory information from the skin mechanoreceptors of the fingertip is of prime importance to modulate grip forces correctly according to load force (LF) variations. In this study, we investigate the EEG responses to LF transients both with and without slippage of the pinched object. Subjects used precision grip to maintain a manipulandum linked to a mechanical device which generated LF variations at the fingertips. The EEG was recorded synchronously. There were two types of LF variations: short range variations without slippage (NS-task) and large variations generating slippage of the finger along the pinched object (S-task). Results showed several differences between the somatosensory evoked potentials (SEP) related to LF transients with or without slippage. In addition to marked shape differences, a significant increase in the amplitude of the SEPs could be observed during the S-task. Despite the small numbers involved and the noisy signals, very similar findings in all subjects indicate that the cortical information related to LF variations is clearly different when the manipulated object is slipping or not. © 2009 Springer Berlin Heidelberg.