Authors:

LEE, A.C.H., Bussey, T.J., Murray, E.A., Saksida, L.M., Epstein, R.A., Kapur, N., HODGES, J.R. & GRAHAM, K.S.

Reference:

Year of publication:

2005

CBU number:

5919

Abstract:

Recent findings from animal studies have lead to suggestions that the medial temporal lobe (MTL), which is thought to subserve memory exclusively1,2, may support non-mnemonic perceptual processes, with the hippocampus and perirhinal cortex contributing to spatial3,4 and object5-7 perception respectively. There has to date, however, been no complementary support for this view in humans, with lesions to the human MTL resulting in prominent memory deficits8-10 in the context of apparently normal perception11-13. Here we assessed fine visual feature discrimination in amnesic cases to reveal that while patients with selective hippocampal damage could discriminate faces, objects, abstract art and colour, they were significantly poorer in the discrimination of spatial scenes. By contrast, patients with MTL damage that included the perirhinal cortex were significantly impaired in the discrimination of scenes, faces, and to a lesser extent objects, in the context of relatively intact discrimination of abstract art and colour. These novel observations imply that the human MTL subserves both perceptual and mnemonic functions, with the hippocampus and perirhinal cortex playing distinct roles in spatial and object discrimination respectively.