Dual-Site Beta tACS Over the rIFG and preSMA-Induced Phase-Specific Changes in Functional Connectivity but not Response Inhibition Performance in Older Adults
Adolescent Adult Aged Aging - physiology Beta Rhythm - physiology Cross-Over Studies Double-Blind Method Electroencephalography Female Humans Inhibition, Psychological Male Middle Aged Motor Cortex - physiology Prefrontal Cortex - physiology Psychomotor Performance - physiology Transcranial Direct Current Stimulation Young Adult
Research suggests that changes in functional connectivity contribute to age-related declines in response inhibition. Through a double-blind crossover study, we investigated the effects of dual-site beta transcranial alternating current stimulation (tACS) over the right inferior frontal gyrus (rIFG) and pre-supplementary motor area (preSMA) on functional connectivity measured with electroencephalography and response inhibition (stop-signal task performance) in 15 older (aged 61-79 years) and 18 young (aged 18-34 years) adults. Two tACS conditions were administered in separate sessions: in-phase tACS, where electrical currents delivered to rIFG and preSMA had a 0° phase difference, and anti-phase tACS, where currents had a 180° phase difference. Resting-state beta band rIFG-preSMA connectivity significantly increased after in-phase tACS for older and young adults and decreased after anti-phase tACS for older adults. Response inhibition significantly improved after both in- and anti-phase tACS for young and older adults. These findings suggest that tACS can potentially modulate rIFG-preSMA connectivity in a phase-specific manner in the aging brain, and that inhibitory performance might not be directly regulated by resting-state rIFG-preSMA phase connectivity. Due to the lack of sham control, placebo effects cannot be ruled out. However, the differing neurophysiological effects from in- and anti-phase tACS suggest that rIFG-preSMA resting-state phase connectivity is unlikely to underpin the changes in inhibitory performance. Future studies incorporating a sham control are required to verify these findings.
Details
Title
Dual-Site Beta tACS Over the rIFG and preSMA-Induced Phase-Specific Changes in Functional Connectivity but not Response Inhibition Performance in Older Adults
Authors/Creators
Jane Tan - Centre for Healthy Ageing, Health Futures Institute, Murdoch University, Perth, Western Australia, Australia
Kartik K Iyer - QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
Michael A Nitsche - Leibniz Research Centre for Working Environment and Human Factors
Rohan Puri - University of Tasmania
Mark R Hinder - University of Tasmania
Hakuei Fujiyama - Murdoch University, Centre for Healthy Ageing
Publication Details
Psychophysiology, Vol.62(5), e70060
Publisher
Wiley Periodicals LLC on behalf of Society for Psychophysiological Research.
Number of pages
13
Grant note
57384703 / Australia-Germany Joint Research Co-operation (DAAD)
DP200101696 / Australian Research Council
711-1641 / Dementia Australia Research Foundation
FT150100406 / Australian Research Council