Abstract
Braver (2012) recently proposed the dual mechanisms of cognitive control (DMC) framework, which postulates that the brain utilises two distinct modes of cognitive control. In Proactive control, selection and suppression relies on a preparatory mechanism (before stimulus presentation) while in reactive control, selection and suppression takes place following stimulus presentation. However, the critical brain mechanisms underlying these modes of control as well as the potential interplay between them are still poorly understood. Previously we have shown that the left intraparietal sulcus (IPS) is critically involved in suppression of salient distractors before their presentation (alluding to its involvement in proactive control; Mevorach et al, 2008). In contrast, the left temporoparietal junction (TPJ) has also been shown to activate (using fMRI) when suppression of salience is called upon (Geng and Vossel, 2013), but this may be when reactive control is needed following stimulus presentation. In the present study we used brain stimulation (TMS) to establish a causal link between the left TPJ and reactive control mode. In order to investigate the interplay between proactive and reactive control we also asked whether interfering with proactive control (in the left IPS) will result with increased utilization of reactive control. We applied offline TMS (1 Hz, at 60% intensity) over the left IPS, the left TPJ, and a control region (Vertex) before participants performed a visual search task for a low contrast target in the presence of either a high or low contrast non-target (which has been shown to rely on reactive control (DiQuattro and Geng, 2011). Our results suggest a critical role for the left TPJ in this task. Furthermore, we found no impact on performance following left IPS stimulation. We conclude that left TPJ and left IPS are differentially involved in reactive and proactive control and that these modes of control act independently.
Meeting abstract presented at VSS 2016