Frontal Theta Oscillations and Cognitive Flexibility: Age-Related Modulations in EEG Activity

Cognitive flexibility, the ability to adapt one’s behaviour in changing environments, declines during aging. Electroencephalography (EEG) studies demonstrate that the P300 and midfrontal theta oscillations are sensitive to attentional set-shifting – a measure of cognitive flexibility. Few is known about the electrocortical modulations underlying set-shifting in healthy older adults. Here, we investigated aging effects on set-shifting performance by analysing the P300 and theta power in 20 young (mean age: 22.5 ± 2.9 years) and 19 older (mean age: 69.4 ± 6.1 years) adults. While increasing shift difficulty (e.g. intra- vs. extra-dimensional shifts) led to increased reaction times (RTs) and higher error rates in both age groups, older adults showed an additional increase in RT variability. Older adults showed higher P300 latencies and P300 amplitude decreased during set-shifting in both groups. Young adults exhibited amplified midfrontal theta power with increasing shift difficulty whereas older adults showed an overall decrease. This study suggests that set-shifting in healthy older adults occurs without midfrontal theta modulation indicating that different neural substrates are recruited compared to young adults.