Control of reaching finger movement accompanied with inhibitory intention

In the present study, we investigated the motor control of reaching finger movement interfered by the inhibitory intention triggered by the stop-signal. In the experiment, the subject started the reaching movement of the index finger with the go-signal of a green LED and stopped the ongoing movement with the stop-signal of a red LED. The stop-signal delay (SSD) was set at 0, 100, 200, 300 and 400 ms. The movement trajectory was measured during the task. The index finger was able to stop prior to the target point when SSD was less than 400 ms, whereas not when SSD was 400 ms. We also measured electroencephalogram (EEG) during the task. A negative peak around the stop-signal response time (SSRT) and a positive peak around 400-600 ms of the event-related potentials (ERPs) were observed at Fz and Cz. These results indicate that these components of the ERPs were associated with the stop-signal task in the human reaching movement.