| Research Abstract |
Inferotemporal cortical area TEO of the macague has been thought to be crucial for pattern perception because of its strong lesion effects on pattern discrimination.In the present study, we reexamined this idea.The motivation rose from an electrophysiological study ; the study mapped the visuotopic organzation of area TEO and excluded from TEO an adjacent superior temporal sulcal area that was ablated in conventional TEO lesions.
First, we examined the effects of gyral area TEO and adjacent superior temporal sulcal area lesions on postoperative retention of preoperatively learned pattern discrimination and postoperative acquisition of new pattern discrimination, and compared them with those of conventional TEO lesions whose dorsal boarder was the floor of the superior temporal sulcus.The gyral area TEO lesions disrupted the performance of the monkeys.However, the degree of the disruption was far smaller than that following the conventional TEO lesions.In addition, the performance of monkeys with the ablation of the superior temporal sulcal area was not differ from that of normal monkeys.
Second, we tested the lesion effects on discrimination limen test for reduced patterns.In this test, too, the gyral TEO lesions resulted in rising of the discrimination limens which was moderate compared with that by the conventional TEO lesions.
The present findings indicated that the gyral TEO lesions produce only slight pattern discrimination deficits and severe pattern discrimination deficits following the conventional TEO lesions resulted from a combined lesion of the gural TEO and adjacent superior temporal sulcal area.
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