Connectivity modulation by dual-site tACS – computational and experimental perspectives

Dual-site transcranial alternating current stimulation (ds-tACS) is often used with the intent to modulate functional connectivity between the two stimulated regions. We previously found that ds-tACS at alpha frequency can modulate resting-state functional connectivity as measured in stimulation-outlasting EEG effects. Nevertheless, both intra- and inter-participant variability were very high at low effect sizes, making it challenging to effectively modulate functional connectivity in single participants, particularly in pathological conditions. In this talk, I will introduce our neural network model to capture the stimulation-outlasting effects of ds-tACS on functional connectivity. We demonstrate that spike-timing dependent plasticity in the model can reproduce the experimentally observed effects, and describe how synaptic delays and tACS cycle lengths determine the change in functional connectivity. Furthermore, we show recent unpublished results on ds-tACS of the primary motor cortices, including a computational study on E-field distributions as well as an fMRI study in which ds-tACS was applied during a bimanual coordination task. Our aim is to use the combination of experimental and computational studies to optimize and personalize ds-tACS to reduce intra- and inter-participant variability, and to provide an efficient tool for noninvasive connectivity modulation.