Poster A95, Saturday, March 25, 5:00 – 7:00 pm, Pacific Concourse
Alpha-frequency transcranial alternating current stimulation (tACS) induces plastic increases in posterior-frontal network connectivity
Kevin Clancy1, Sarah Baisley1, Nika Kartvelishvili1, Mingzhou Ding2, Wen Li1; 1Florida State University, 2University of Florida - Gainesville
Alpha oscillations (8-12 Hz) play a significant role in a variety of cognitive and sensory processes by mediating long-range network communications. Recent work attempts to modulate alpha oscillations using transcranial alternating current stimulation (tACS) at the alpha frequency. The long-term effects of alpha modulation, however, have not been established. We addressed this issue by administering high-density (HD) tACS (30 minutes at 1-2 mV; individual peak alpha frequency/PAF; midline parieto-occipital POz site) in healthy subjects (n= 13; with a sham-control group) over four consecutive days. We found that (1) alpha stimulation increased posterior alpha power immediately and 30 minutes post-stimulation on both Day 1 and Day 4, which was paralleled by the same pattern of increase in ipsilateral bottom-up causal connectivity (indexed by Granger Causality; GC; p’s < .05), and (2) the magnitude of power change and the magnitude of GC change were significantly correlated (r =.60, p < .05). Furthermore, bottom-up GC showed a sustained augmentation from Day 1 to Day 4. No such effects were observed in the sham control group (p’s > .16). These results suggest that alpha tACS can be used to affect long-term plastic changes in alpha power and alpha network communication. That local posterior modulation of alpha oscillations can alter posterior-frontal causal connectivity implicates a role of sensory processing and sensory input in influencing higher-order cognitive processes. The long-term plastic effects also provide support for alpha tACS as a viable treatment for psychiatric and neurological disorders that are characterized by impaired oscillatory activities.
Topic Area: METHODS: Electrophysiology