Perturbation of theta-gamma coupling at the temporal lobe hinders verbal declarative memory

Autor: Ivan Alekseichuk, Gabriel Amador de Lara, Andrea Antal, Albert Lehr, Zsolt Turi, Walter Paulus
Rok vydání: 2017
Předmět:
Zdroj: Brain Stimulation, Vol 11, Iss 3, Pp 509-517 (2018)
ISSN: 1876-4754
Popis: Background: Phase-amplitude cross-frequency coupling (PAC) is characterized by the modulation of the power of a fast brain oscillation (e.g., gamma) by the phase of a slow rhythm (e.g., theta). PAC in different sub- and neocortical regions is known to underlie effective neural communication and correlates with successful long-term memory formation. Objective/Hypothesis: The present work aims to extend earlier observational data, by probing the functional role of theta-gamma PAC in the left temporal cortex in humans during verbal long-term memory encoding. Methods: In three double-blinded, placebo-controlled experiments (n = 72), we employed cross-frequency transcranial alternating current stimulation (tACS) to externally modulate ongoing PAC during a verbal-associative learning task. Three types of cross-frequency tACS protocols were used: bursts of high gamma tACS were coupled to the peak or trough of the theta tACS cycle, and a control condition where gamma tACS was continuously superimposed at theta tACS cycles. Results: Gamma bursts coupled to the trough of theta tACS induced robust behavioral impairment in memory performance (p
Databáze: OpenAIRE