A pencil rescues impaired performance on a visual discrimination task in patients with medial temporal lobe lesions
- 1Veterans Affairs San Diego Healthcare System, San Diego, California 92161, USA
- 2Department of Psychology and Neuroscience Center, Brigham Young University, Provo, Utah 84143, USA
- 3Department of Medicine, Pulmonary and Critical Care Division, Intermountain Medical Center, Murray, Utah 84143, USA
- 4Department of Psychology, University of California, San Diego, California 92093, USA
- 5Department of Psychiatry, University of California, San Diego, California 92093, USA
- 6Department of Neurosciences, University of California, San Diego, California 92093, USA
Abstract
We tested proposals that medial temporal lobe (MTL) structures support not just memory but certain kinds of visual perception as well. Patients with hippocampal lesions or larger MTL lesions attempted to identify the unique object among twin pairs of objects that had a high degree of feature overlap. Patients were markedly impaired under the more difficult task conditions. However, the deficit was fully rescued when patients used a pencil to draw lines between the twin pairs, thereby eliminating the need to hold material in memory as they worked at each display. The perceptual demands of the task were presumably the same with or without this memory aid. Accordingly, the results suggest that the deficit on this and similar tasks, which involve comparisons across stimuli, are better understood in terms of impaired memory rather than impaired perception.
Footnotes
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↵7 Corresponding author
E-mail lsquire{at}ucsd.edu
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[Supplemental material is available for this article.]
- Received July 16, 2013.
- Accepted August 6, 2013.
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