Abstract
We investigated the processing of stimuli associated with behavioral inhibition. Different target colors told participants to either execute the response (go trial) or to withhold the response (nogo trial). Four letters appeared in each of four placeholders but only the target was colored. On go trials, participants had to indicate the identity of the target letter by pressing one of two keys. The cue disks appeared 150 ms before target onset and were displayed around the four placeholder boxes in which the letters were displayed. One set of cue disks was colored. Cue and target color were equal on 50% of trials. The cue position did not predict the target position, but behavioral results showed faster responses with valid cues on go-trials. The EEG results showed that the cues in the color of the nogo-target triggered a Pd, whereas the cues in the color of the go-target triggered an N2pc. The N2pc component was considered a measure of attentional capture whereas the distractor positivity (Pd) is assumed to reflect attentional suppression. Our findings suggest that processing of the colored cue was modulated by the response requirements associated with the two colors. The intention to inhibit a response led to attentional suppression of the associated color, whereas the intention to respond led to attentional enhancement, even when the cue required no response. Thus, the attentional enhancement or suppression serves to prepare behavioral decisions.
Meeting abstract presented at VSS 2015