Event-related delta and theta brain oscillations reflect age-related changes in both a general and a specific neuronal inhibitory mechanism

Objective: ERPs may be limited in validity when investigating inhibitory functions in later adulthood, as age-related increases in intraindividual variability and changes in EEG-oscillations are not considered. The present study compared averaged ERP peak and single trial time-frequency (TF) data analysis. Methods: Go/NoGo ERP waves amplitude/latency measures were compared with a TF analysis estimating single trial event-related EEG spectral power enhancement and intertrial phase-locking (ITC) in delta and theta band. Results: Age-related larger ITC was found for theta oscillations in the N2-P3 time range during NoGo, only. Discrepancies between N1/N2 ERP and TF results were obtained. Go/NoGo-P3 amplitude reductions in elderly were not related to an increased delta latency jitter. Conclusions: Discrepancies between ERPs and TF results challenge conclusions made about age-related changes in Go/NoGo-N2. Earlier reports of age-related changes in P3 are supported by the present results. The study implies age-related impairments in a general neuronal inhibition mechanism and a specific response inhibition mechanism. Significance: The study indicates long-range communication impairments in the aged brain and the results are discussed considering hypotheses on increases in neural noise. (C) 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.