Visual-spatial episodic memory in schizophrenia: A multiple systems framework

Enhanced understanding of cognitive deficits, and the neurobiological abnormalities that mediate them, can be achieved through translational research that employs comparable experimental approaches across species. This study employed a multiple-systems framework derived from the rodent literature to investigate visual-spatial memory abilities associated with schizophrenia.

Using the bin task, a human analog of rodent maze tasks, everyday objects were hidden in visually identical bins. Following a 1-min filled delay, participants with schizophrenia-spectrum disorders (n = 30) and healthy community controls (n = 30) were asked to identify both the object hidden and bin used on the basis of its spatial location. Three dimensions of visual-spatial memory were contrasted: (a) memory for spatial locations versus memory for objects, (b) allocentric (viewpoint independent) versus egocentric (body-centered) spatial representations, and (c) event (working) memory versus reference memory.

Most pronounced was a differential deficit in memory for spatial locations under allocentric (p = .005, d = -0.77) but not egocentric viewing conditions (p = .298, d = -0.28) in the schizophrenia group relative to healthy controls. Similarly, schizophrenia-related spatial memory deficits were pronounced under demands for event memory (p = .004, d = -0.77) but not reference memory (p = .171, d = -0.33).

These results support a heuristic of preferential deficits in hippocampal-mediated forms of memory in schizophrenia. Moreover, the task provides a useful paradigm for translational research and the pattern of deficits suggests that persons with schizophrenia may benefit from mnemonic approaches favoring egocentric representations and consistency when interacting with our visual-spatial world.