Human hippocampus and viewpoint dependence in spatial memory.
Virtual reality was used to sequentially present objects within a town square and to test recognition of object locations from the same viewpoint as presentation, or from a shifted viewpoint. A developmental amnesic case with focal bilateral hippocampal pathology showed a massive additional impairment when tested from the shifted viewpoint compared with a mild, list length-dependent, impairment when tested from the same viewpoint. While the same-view condition could be solved by visual pattern matching, the shifted-view condition requires a viewpoint independent representation or an equivalent mechanism for translating or rotating viewpoints in memory. The latter mechanism was indicated by control subjects' response latencies in the shifted-view condition, although the amnesic case is not impaired in tests of mental rotation of single objects. These results show that the human hippocampus supports viewpoint independence in spatial memory, and suggest that it does so by providing a mechanism for viewpoint manipulation in memory. In addition, they suggest an extremely sensitive test for human hippocampal damage, and hint at the nature of the hippocampal role in episodic recollection.
King
John A
JA
Institute of Cognitive Neuroscience and Department of Anatomy, University College, London, United Kingdom. john.king@ucl.ac.uk
Burgess
Neil
N
Hartley
Tom
T
Vargha-Khadem
Faraneh
F
O'Keefe
John
J
D000328:Adult; D001238:Asphyxia Neonatorum / Q000150:complications; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000150:complications; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D008569:Memory Disorders / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D011597:Psychomotor Performance; D013028:Space Perception / Q000502:physiology*; D014584:User-Computer Interface