Saturday, October 01st, 2011 [08:30 - 08:50]
Insights into response capture and inhibition with Transcranial magnetic stimulation
van Campen, D. , van den Wildenberg, W. P. & Ridderinkhof, K. R.
University of Amsterdam
Selective inhibitory control when selecting between two actions is an important aspect of goal-directed behavior. In the Simon task, participants respond to a relevant feature (color) while ignoring an irrelevant feature (location). The goal of the experiments is to link behavioral indices of top-down suppression of involuntary response impulses and response capture with physiological markers. In two experiments we collected data with single pulse and repetitive Transcranial Magnetic Stimulation (spTMS and rTMS). Behavioral data was assessed in all experiments, using RT distribution analyses and conditional accuracy functions (CAF). In the first experiment spTMS is applied over motor cortex at different timing moments to link behavioral inhibition with physiological markers and to track its time course. In the second experiment 1hz offline rTMS was applied over the pre-supplementary motor area (pre-SMA) and right inferior frontal gyrus (rIFG) to interfere with the function of the two cortical areas. The spTMS results showed an early increase in M1 activation indicative of response capture, followed by cortical inhibition on correct interference trials. Preliminary data from the rTMS-experiment point to more partial errors after pre-SMA stimulation, indicating impaired response selection. Secondly, rIFG stimulation seems to enhance interference effects, suggesting impaired selective suppression of irrelevant information.