NOVELTY DETECTION AND AGING: PSYCHOPHYSIOLOGICAL INVESTIGATIONS
Stimuli outside the task-set ('novelty stimuli') may initiate the processes of the orientation complex. These processes comprise the activity of neural networks contributing to the emergence of N2b and P3a/P3novelty components of event-related potentials. In the elderly these components have longer latency and smaller amplitude for auditory as well as visual stimuli. Delayed latency corresponds to the slowing of mental processes in the elderly. Amplitude change may be due to compromised inhibitory processes. The age-related change of the efficiency of inhibitory processes is evidenced by the decreased habituation of the orientation-related event-related potential components. In younger participants P3a/P3novelty habituation is evident within an experimental session, within the blocks of the session and even for the repeated presentation of the same stimulus. No such habituation processes were detected in the elderly. According to the results of three studies in the visual modality, N2b is related to the conflict between the processing of the incoming novelty stimuli and the response requirements of the representation of the incoming task.
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