?-? Cross-Frequency Transcranial Alternating Current Stimulation over the Trough Impairs Cognitive Control.

ABSTRACT: Cognitive control is a mental process, which underlies adaptive goal-directed decisions. Previous studies have linked cognitive control to electrophysiological fluctuations in the ? band and ?-? cross-frequency coupling (CFC) arising from the cingulate and frontal cortices. However, to date, the behavioral consequences of different forms of ?-? CFC remain elusive. Here, we studied the behavioral effects of the ?-? CFC via transcranial alternating current stimulation (tACS) designed to stimulate the frontal and cingulate cortices in humans. Using a double-blind, randomized, repeated measures study design, 24 healthy participants were subjected to three active and one control CFC-tACS conditions. In the active conditions, 80-Hz ? tACS was coupled to 4-Hz ? tACS. Specifically, in two of the active conditions, short ? bursts were coupled to the delivered ? cycle to coincide with either its peaks or troughs. In the third active condition, the phase of a ? cycle modulated the amplitude of the ? oscillation. In the fourth, control protocol, 80-Hz tACS was continuously superimposed over the 4-Hz tACS, therefore lacking any phase specificity in the CFC. During the 20 min of stimulation, the participants performed a Go/NoGo monetary reward-based and punishment-based instrumental learning task. A Bayesian hierarchical logistic regression analysis revealed that relative to the control, the peak-coupled tACS had no effects on the behavioral performance, whereas the trough-coupled tACS and, to a lesser extent, amplitude-modulated tACS reduced performance in conflicting trials. Our results suggest that cognitive control depends on the phase specificity of the ?-? CFC.

SUBMITTER: Turi Z 

PROVIDER: S-EPMC7540931 | biostudies-literature | 2020 Sep/Oct

REPOSITORIES: biostudies-literature