Item and order dissociation in humans with prefrontal cortex damage.

Subjects with bilateral, right or left prefrontal cortex damage and age matched controls were tested for item and order recognition memory for spatial location, word, abstract picture and hand position information. Prefrontal cortex damaged subjects showed, in general, no deficits on item recognition tests relative to controls with the exception of a deficit for hand positions. In contrast, prefrontal cortex damaged groups had severe deficits on all order recognition tests relative to controls. With respect to lateralization, order recognition memory deficits occurred for right, bilateral, but not left prefrontal cortex damaged subjects for spatial location information, but for both right and left prefrontal cortex damaged subjects for words, abstract pictures, and hand position. The data suggest that the prefrontal cortex mediates temporal order information for all modalities tested as well as item recognition memory for egocentric spatial information.