Neuro-compensatory changes in face recognition in older adults: evidence from evoked and oscillatory responses of event-related potentials

Although face recognition is an essential function for human social interaction, face identification, memory retention, and processing speed decline with age. Recent event-related potential studies suggest that aging effects occur at relatively early perceptual stages; age-related increases in amplitude and latency and reduced hemispheric lateralization of the N170 component have been noted. However, studies into the P100 component have been sparse and yielded inconsistent findings. Here, we measured event-related potentials during face stimulus presentation in young (n = 22) and older (n = 22) adults. We focused on neuronal transients (P100 and N170) that are phase-locked to the stimulus, thereby reflecting changes in neuronal input. We also analyzed the oscillatory activities of P100 and N170, whose latencies fluctuate from trial to trial; this signaled the coupling mechanisms of each trial. We observed significant age-related differences in both P100 and N170. Notably, although older adults did not exhibit the characteristic right hemispheric predominance observed in young adults, they still demonstrated the preserved face inversion effect. Intertrial phase coherence analysis revealed lower phase synchronization in the older adults than in the young adults. Our findings suggest that age-related functional changes in the primary visual cortex influence the P100 component, and that the reduced right hemispheric predominance of N170 may be attributed to neural compensation. Thus, neural specificity for face recognition appears to be preserved in older adults, counterbalancing the aging effect. Moreover, intertrial phase coherence measurements indicate that the age-related decline in face recognition may be explained by asynchronous phase-locking neural activity in the face-specific area.