Impoverished descriptions of familiar routes in three cases of hippocampal/medial temporal lobe amnesia.
Recent research has challenged classic theories of hippocampal function in spatial memory with findings that the hippocampus may be necessary for detailed representations of environments learned long ago, but not for remembering the gist or schematic aspects that are sufficient for navigating within those environments (Rosenbaum et al., 2000; Rosenbaum, Winocur, Binns, & Moscovitch, 2012). We aimed to probe further distinctions between detailed and schematic representations of familiar environments in three cases of hippocampal/medial temporal lobe (MTL) amnesia by testing them on a route description task and mental navigation tasks that assess the identity and location of landmarks, and distances and directions between them. The amnesic cases could describe basic directions along known, imagined routes, estimate distance and direction between well-known landmarks, and produce sketch maps with accurate layouts, suggestive of intact schematic representations. However, findings that their route descriptions lack richness of detail, along with impoverished sketch maps and poor landmark recognition, substantiates previous findings that detailed representations are hippocampus-dependent.
York University, Toronto, Ontario, Canada. Electronic address: kherdman@yorku.ca.
Katherine A
KA
Herdman
York University, Toronto, Ontario, Canada.
Navona
N
Calarco
Rotman Research Institute, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada.
Morris
M
Moscovitch
University of Toronto, Toronto, Ontario, Canada.
Marnie
M
Hirshhorn
York University, Toronto, Ontario, Canada; Rotman Research Institute, Toronto, Ontario, Canada. Electronic address: shaynar@yorku.ca.
R Shayna
RS
Rosenbaum
D000328:Adult; D000368:Aged; D000647:Amnesia / Q000209:etiology / Q000473:pathology* / Q000523:psychology; D004215:Distance Perception; D020803:Encephalitis, Herpes Simplex / Q000150:complications / Q000473:pathology / Q000523:psychology; D016489:Head Injuries, Closed / Q000150:complications / Q000473:pathology / Q000523:psychology; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology*; D009949:Orientation; D011597:Psychomotor Performance; D013028:Space Perception; D013702:Temporal Lobe / Q000473:pathology*
Case study method; Episodic memory; Hippocampus; Navigation; Spatial memory