Visual recognition and recall after right temporal-lobe excision in man

A further effort was made to determine the effects of right anterior temporal lobectomy in man on visual perception and visual memory. Groups of patients with cortical resections from right or left temporal, frontal, or parietal regions were required to recognize photographs of faces within a larger array, after having been shown the faces previously. Three variations of this task were used: in the first, the interval between initial presentation and recognition test was filled with an irrelevant visual task. In the second, the delay remained but the interpolated task was omitted. In the third, there was only minimal delay ("immediate recognition"). On the first two tasks, patients with right temporal-lobe lesions had marked deficits compared with all other groups, but on the third task (minimal delay) no clearcut group differences were seen, because the normal control group did worse than with delay. Normal subjects (unlike patients with right temporal-lobe excisions) apparently use the delay period to consolidate and possibly recode their visual impressions. In the context of other tasks sensitive to right temporal-lobe lesions, the findings suggest a mild impairment in the perception of complex patterns after right anterior temporal lobectomy, and a much more severe one in the retention of the perceived material.