Neural mechanism of response inhibition in a Go/NoGo tasks

In study of response inhibition processes using ´Go/NoGo´ task, a deconvolution computation technique is adapted to recover pure stimulus and response signals, hence avoid the inferential effect of the movement-related potentials that arise from motor response to the stimulus. Meanwhile, in order to present the ERP information (spatial distribution and time course) of different experiment tasks, a new common spatial pattern algorithm is designed and applied to the ERP data of Go/NoGo tasks. The result shows that NoGo trials contain a special P3 component, located in motor related cortex. This component reflects the additive effect of a response inhibition process in the NoGo task. Through a current source density analysis by LORETA, the source of NoGo N2 is located in right Anterior Cingulate area and right Medial Frontal Gyrus (BA 32) and the source of NoGo P3 is located in Superior Frontal Gyrus (BA6). This result suggests that the response inhibition includes two stages: in first stage, NoGo N2 component reflects inhibition of response preparation; and in the second stage, NoGo P3 component reflects inhibition of response execution.