Search

Introduction: Theta-phase gamma-amplitude coupling (TGC) measurement has recently received attention as a feasible method of assessing brain functions such as neuronal interactions. The purpose of this electroencephalographic (EEG) study is to understand the mechanisms underlying the deficits in attentional control in children with attention deficit/hyperactivity disorder (ADHD) by comparing the power spectra and TGC at rest and during a mental arithmetic task. Methods: Nineteen-channel EEGs were recorded from 97 volunteers (including 53 subjects with ADHD) from a camp for hyperactive children under two conditions (rest and task performance). The EEG power spectra and the TGC data were analyzed. Correlation analyses between the Intermediate Visual and Auditory (IVA) continuous performance test (CPT) scores and EEG parameters were performed. Results: No significant difference in the power spectra was detected between the groups at rest and during task performance. However, TGC was reduced during the arithmetic task in the ADHD group compared with the normal group (F = 16.70, p < 0.001). The TGC values positively correlated with the IVA CPT scores but negatively correlated with theta power. Conclusions: Our findings suggest that desynchronization of TGC occurred during the arithmetic task in ADHD children. TGC in ADHD children is expected to serve as a promising neurophysiological marker of network deactivation during attention-demanding tasks. [ABSTRACT FROM AUTHOR]

Abstract: Theta–gamma coupling (TGC) is known to reflect working memory processes, but it is unclear whether TGC as measured by scalp electroencephalography (EEG) reflects working memory processes or nonspecific attentional processes. In this study, we examined the degree of TGC during a visuo-spatial working memory task (2-back task) vs. a simple vigilance task in 13 young participants. During the working memory task, TGC increased in the frontal area at approximately 40Hz. In addition, TGC was also significantly different at high-gamma frequency despite no differences in gamma power between the two tasks, and a correlation between TGC only during the working memory task and hit rate was observed. These results suggest that TGC reflects working memory processes and may be a useful bio-physiological marker of working memory. [Copyright &y& Elsevier]