Abstract
Cognitive control can involve proactive and reactive mechanisms. Little is known about pro- and reactive control in visual search, when observers look for pre-defined targets among distractors. Using a gaze-contingent eye-tracking paradigm, we recently provided evidence consistent with different modes of control in multiple-target search. We instructed participants to simultaneously search for two possible target objects presented among distractors, and select one of them. In one condition, only one of the two targets was available in each display, so that the choice was imposed, and a reactive control mechanism would be required. In the other condition, both targets were present in a search display, which gave observers free choice over what to search for, and allowed for proactive control. Switch costs emerged when targets were imposed, while no switch costs emerged when target selection was free. Using a unique combination of fMRI with the same fast-paced gaze-contingent eye-tracking paradigm, we examined which cortical regions were selectively activated by proactive and reactive control mechanisms during multiple-target search. Based on earlier findings, we expected regions in the lateral prefrontal cortex to be active during both types of control. Results indeed support the involvement of the fronto-parietal attention network, including SMA/pre-SMA, anterior cingulate cortex, intraparietal sulcus, precuneus, and anterior insula, both when choice was imposed and when it was free. Moreover, we found activations in the frontopolar cortex specific for the free choice conditions, which supports the recent idea that the frontopolar cortex is involved in evaluating alternative goals. Finally, we present the results of a deconvolution analysis to uncover any differences in the time course of activations associated with different modes of control.
Meeting abstract presented at VSS 2018