Altered duration of alpha brain oscillations during sensory and cognitive processing in elderly
Schmiedt-Fehr, C., and Basar-Eroglu, C.
Institut für Psychologie und Kognitionsforschung, Universität Bremen
Previous studies indicate age-related changes in oscillatory networks associated with sensory processing. This study investigates age-related changes in oscillations during a visual oddball task. Delta (0.5-3 Hz), theta (4-7 Hz), alpha (8-13 Hz), and gamma (28-48 Hz) oscillatory activity, was analysed across early versus late blocks of trials in healthy young (n=20, 25±4 years) and older individuals (n=20, 61±5 years), during the processing of target and standard stimuli. Maximum amplitude values derived from FFT filtered and subsequently averaged data provided the database for the computation of amplitude and distribution differences between age-groups during early and late blocks of trials. Results show 1) a shift of delta activity to anterior locations, 2) a frontal alpha response with earlier onset, but shorter duration, and 3) reduced delta and theta amplitudes in older individuals compared to young. The findings are congruent with previous studies, showing altered frontal oscillatory networks in older individuals.