Lecture by Yuranny Cabral-Calderin: Combining transcranial
alternating current stimulation with fMRI to study bistable perception

Brain oscillations are regarded as important for perception. Using bistable perception tasks in combination with electrophysiological techniques, past studies probed a correlative link between brain oscillations and perception. However, correlative links could represent epiphenomena of the percept. The emergence of noninvasive brain stimulation techniques such as transcranial alternating current stimulation (tACS) provides the possibility to expand correlational approaches to investigate the causal contribution of specific oscillatory frequencies to perception. In this talk, I will present results from different studies where we 1) employed tACS to test the causality of alpha and gamma oscillations for bistable perception and 2) combined tACS with functional magnetic resonance imaging (fMRI) to evaluate the effects of the stimulation on brain function. The main findings suggest a causal role of gamma oscillations in occipito-parietal areas for the resolution of perceptual ambiguity, and a susceptibility of fronto-parietal regions to be modulated by tACS.