Aging changes in the cat P300 mimic the human.

Long-latency endogenous responses with characteristics of the human P300 were recorded from young cats (1-3 years). Principal components analysis and paired t tests confirmed that responses within a 200-300 msec latency window were significantly larger to rate stimuli than to frequent stimuli. In contrast, a similar study of long-latency responses in old cats (more than 10 years) showed no significant difference between the 'rare' and 'frequent' responses. These data indicate that the P300 changes functionally with old age in the cat, as in the human, and that the cat provides an important model for P300 generator analysis in the aged as well as in the young brain.