Age-related changes of frontal-midline theta is predictive of efficient memory maintenance.

Frontal areas are thought to be the coordinators of working memory processes by controlling other brain areas reflected by oscillatory activities like frontal-midline theta (4-7 Hz). With aging substantial changes can be observed in the frontal brain areas, presumably leading to age-associated changes in cortical correlates of cognitive functioning. The present study aimed to test whether altered frontal-midline theta dynamics during working memory maintenance may underlie the capacity deficits observed in older adults. 33-channel EEG was recorded in young (18-26 years, N=20) and old (60-71 years, N=16) adults during the retention period of a visual delayed match-to-sample task, in which they had to maintain arrays of 3 or 5 colored squares. An additional visual odd-ball task was used to be able to measure the electrophysiological indices of sustained attentional processes. Old participants showed reduced frontal theta activity during both tasks compared to the young group. In the young memory maintenance-related frontal-midline theta activity was shown to be sensitive both to the increased memory demands and to efficient subsequent memory performance, whereas the old adults showed no such task-related difference in the frontal theta activity. The decrease of frontal-midline theta activity in the old group indicates that cerebral aging may alter the cortical circuitries of theta dynamics, thereby leading to age-associated decline of working memory maintenance function.

Aging effects on ERP correlates of emotional word discrimination.

OBJECTIVE: To explore age-, and valence specific ERP-characteristics of word-discrimination processes. METHODS: A group of young (mean age: 21.26 yrs) and elderly (mean age: 65.73 yrs) individuals participated. The task was to respond to a word (target) with valence (neutral, negative, positive) and disregard others (non-target) with a different valence. Behavioral indices and the N4 and late positive complex (LPC) components were analyzed. RESULTS: For words with negative valence performance was better for non-target stimuli in the young. Higher N4 was elicited by negative non-target words in the fronto-central areas. Target words elicited a P3b-like LPC in the young while a P3a-like LPC was observed in the elderly. CONCLUSION: The findings indicate that inhibition elicited by aversive events is observed for word stimuli as well, and is most effective in the young. SIGNIFICANCE: The effect of valence during emotional word discrimination shows age-dependent differences reflected by ERPs.