Brain-state determines learning improvements after transcranial alternating-current stimulation to frontal cortex

Publication date: Available online 17 February 2018
Source:Brain Stimulation
Author(s): John Nguyen, Yuqi Deng, Robert M.G. Reinhart
BackgroundTheories of executive control propose that communication between medial frontal cortex (MFC) and lateral prefrontal cortex (lPFC) is critical for learning. 6-Hz phase synchronization may be the mechanism by which neural activity between MFC and lPFC is coordinated into a functional network. Recent evidence suggests that switching from eyes closed to open may induce a change in brain-state reflected by enhanced executive control and related functional connectivity.Objective/HypothesisTo examine whether causal manipulation of MFC and lPFC can improve learning according to the brain-state induced by switching from eyes closed to open.MethodsWithin-subjects, sham-controlled, double-blind study of 30 healthy subjects, each receiving 6-Hz in-phase high definition transcranial alternating-current stimulation (HD-tACS) applied to MFC and right lPFC prior to performing a time estimation task.ResultsHD-tACS with eyes open improved learning ability relative to sham, whereas HD-tACS with eyes closed had no significant effect on behavior.ConclusionResults suggest a phase-sensitive mechanism in frontal cortex mediates components of learning performance in a state-dependent manner.



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