Abstract
To investigate the prefrontal neuronal mechanism for mnemonic process of multiple objects and their order of presentation, we recorded neuronal activity from lateral prefrontal cortex while two monkeys performed a serial probe reproduction task, in which two sequentially presented objects (C1 and C2) were memorized and then select one target object from two memorized objects based on the color stimulus. Of 611 recorded neurons, 131 neurons showed object-selective delay-period activity during first delay after C1 (D1) and/or second delay after C2 (D2) periods. Forty-seven neurons showed the C1-coding delay-period activity, which was found during D1 and/or D2 periods when preferred object was presented during the C1 period, but not found when the preferred object was presented during the C2 period. Forty-three neurons showed the C2-coding delay-period activity, which was found during D2 period when preferred object was presented during the C2 period, but not found when the preferred object was presented during the C1 period. During the error trials, the C1-coding and C2-coding delay-period activities were decreased. The neurons with the C1-coding and C2-coding delay-period activities did not exhibit object selective activity during the delayed matching to sample task. The C1-coding and C2-coding delay-period activities were recorded from the ventral portion of the lateral prefrontal cortex (VLPFC). These results suggest that the VLPFC plays a role in holding information of both the object and the temporal order of presentation. [Jpn J Physiol 54 Suppl:S190 (2004)]
