Attention and control of manual responses in cognitive conflict: Findings from TMS perturbation studies

The article reviews studies that have used the perturbation approach of Transcranial Magnetic Stimulation (TMS) to assess the control of attention and manual response selection in conflict situations as elicited in three established paradigms: the Simon paradigm, the Flanker paradigm, and the Stroop paradigm. After describing the experimental conflict paradigms and briefly introducing TMS we review evidence for the involvement of different frontal and parietal cortical regions in the control of attention and response selection. For example, areas such as the frontal eye field (FEF) appear to significantly contribute to the encoding of spatial attributes of stimuli and areas of the parietal cortex, such as angular gyrus (AG), mediate the allocation of spatial attention and orienting. The dorsal medial frontal cortex (dMFC), supramarginal gyrus (SMG) and pre-supplementary motor area (pre-SMA) appear to be more related to response-related aspects of the conflicts (i.e., enhancement of signals related to correct movements, transformation of spatial information action codes, resolution of response selection conflicts, respectively). The reviewed studies illustrate crucial benefits but also limitations of TMS as well as the value of the combination of TMS with other methods. We suggest topics and approaches for future studies.