The Quarterly Journal of Experimental Psychology

Abstract

This paper reviews evidence from neuropsychological patient studies relevant to two questions concerning the functions of the medial temporal lobe in humans.The first is whether the hippocampus and the adjacent perirhinal cortex make different contributions to memory.Data are discussed from two patients with adult-onset bilateral hippocampal damage who show a sparing of item recognition relative to recall and certain types of associative recognition.It is argued that these data are consistent with Aggleton and Brown's (1999) proposal that familiarity-based recognition memory is not dependent on the hippocampus but is mediated by the perirhinal cortex and dorso-medial thalamic nucleus.The second question is whether the recognition memory deficit observed in medial temporal lobe amnesia can be explained by a deficit in perceptual processing and representation of objects rather than a deficit in memory per se.The finding that amnesics were impaired at recognizing, after short delays, patterns that they could successfully discriminate suggests that their memory impairment did not result from an objectprocessing deficit.The possibility remains, however, that the human perirhinal cortex plays a role in object processing, as well as in recognition memory, and data are presented that support this possibility.The medial temporal lobes are known to play a critical role in declarative memory (memory for facts and events) in humans, but it is currently unresolved whether the hippocampus and the adjacent medial temporal lobe cortices (entorhinal, perirhinal, and parahippocampal cortices) make distinct contributions to memory, and, if so, what these contributions are.Furthermore, recent work with nonhuman primates has suggested that the role of the perirhinal cortex may not be exclusively one of memory.The current paper focuses primarily on two issues: first, whether recognition memory for individual items in humans is dependent on the integrity of the hippocampus or whether it can be mediated by adjacent cortical regions such as the perirhinal cortex; second, whether the object recognition memory deficit observed in amnesics with medial temporal lobe lesions can be explained by