Abstract
Face processing is one of the most developed visual skills in humans, giving us the ability to quickly and accurately perceive the unique identity of an individual and guide our social interactions. Functional magnetic resonance imaging (fMRI) shows that brain areas such as the fusiform face area (FFA), the superior temporal sulcus (STS), and the occipital face area (OFA) form a network of key face processing regions. We sought to measure the level of functional synchrony within and across hemispheres in the face network. We measured the effect of repetitive transcranial magnetic stimulation (rTMS) to the right OFA on BOLD signal within the face network using a consecutive TMS-fMRI paradigm. Participants underwent 20 min of 1Hz rTMS followed by an fMR-adaptation paradigm. In separate sessions in counterbalanced order, rTMS was delivered in three different conditions: 1) rTMS to the right OFA, 2) sham rTMS, and 3) the control region, right lateral occipital area (LO). rTMS was immediately followed by a face-adaptation fMRI task to measure its effects on BOLD signal. Prior to the rTMS sessions participants underwent two functional localizers in order to extract individual face-processing regions-of-interest (ROIs). Individual Pearson's Correlation Coefficient (PCC) matrices were constructed across ROIs in the different TMS conditions. There was a general increase in the correlation between FFA and OFA BOLD signal in the right and left hemispheres after rTMS to the right OFA compared to sham and TMS to LO conditions. TMS to the OFA reduced BOLD signal, which correlated with a reduction in BOLD signal in the left OFA and bilateral FFA. These results are consistent with previous findings showing that TMS to the OFA has remote effects in the FFA both within and across hemispheres.
Meeting abstract presented at VSS 2016