Project: Transcranial brain stimulation investigations on the role of oscillatory phase in neuronal processing
Summary: Recently there has been surge in the interest on slow neuronal oscillations (delta, theta and alpha activity) in both animals and humans. While these oscillations often correlate with behaviour, it is unknown to what extent they play a causal role for neuronal processing. The aim of this proposal is to gain insight into the mechanist role of slow oscillations by using transcranial stimulation in humans in order to induce and perturb neuronal oscillations. This will be done in the context of a set of experiments where we combine electroencephalography (EEG) with transcranial magnetic stimulation (TMS) or transcranial alternating current stimulation (tACS). Our first aim is to determine the conditions for when oscillatory activity induced by transcranial stimulation can be considered similar to naturally occurring neuronal oscillations. The second aim is to demonstrate that neuronal oscillations play a causal role for routing of information between brain networks. Finally, a recent theoretical framework published by our group predicts that different information is encoded at different phases of the oscillatory cycles (‘phase coding’). We will test this hypothesis by perturbing perception in a phase-dependent manner. We expect our studies to provide novel insight into the causal role of slow oscillations. This insight is important for understanding how neuronal processing is timed and the routing between regions. Further, this insight can potentially be used to augment human performance by controlling brain states using transcranial stimulation.