CBSU bibliography search
To request a reprint of a CBSU publication, please click here to send us an email (reprints may not be available for all publications)
Knowing where and knowing what: A double dissociation.
Wilson, B.A., Clare, L., Young, A., & Hodges, J.
Cortex, 33, 529-541
Year of publication:
We report a double dissociation between visuo-spatial abilities and semantic knowledge, in two brain-injured people with longstanding stable impairments, using a wide range of tests to explore the extent of the dissociation. MU, who has bilateral lesions of occipito-parietal cortex, shows severe spatial disorientation with intact semantic knowledge. He is contrasted with JBR, who has bilateral temporal lobe damage and shows severe semantic problems and no impairment on visuo-spatial tasks. Our findings thus show a classical double dissociation between the performance of semantic and spatial tasks by MU and JBR, in which the performance of one person is normal when the other person is impaired. This pattern is consistent with Ungerleider and Mishkin's (1982) neurophysiological hypothesis of separable cortical visual pathways; one which is specialised for spatial perception and follows a dorsal route from occipital to parietal lobes, and the other following a more ventral route from occipital to temporal lobes, whose target is semantic information needed in specifying what an object is.