Visual implicit memory in the left hemisphere: evidence from patients with callosotomies and right occipital lobe lesions

Authors:

  • Andrew P. Yonelinas

  • Neal E. A. Kroll

  • Kathleen Baynes

  • Ian G. Dobbins

  • C.M. Frederick

  • Robert T. Knight

  • Michael S. Gazzaniga

Date: 2001

PubMed: 11476095

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Abstract:

Identification of visually presented objects and words is facilitated by implicit memory for past visual experiences with those items. Several behavioral and neuroimaging studies suggest that this form of memory is dependent on perceptual processes localized in the right occipital lobe. We tested this claim by examining implicit mem- ory in patients with extensive right occipital lobe lesions, using lexi- cal-decision, mirror-reading, picture-fragment, and word-fragment- completion tests, and found that these patients exhibited normal levels of priming. We also examined implicit memory in patients with com- plete callosotomies, using standard and divided-visual-field word- fragment-completion procedures, and found that the isolated left hemisphere exhibited normal priming effects. The results indicate that the right occipital lobe does not play a necessary role in visual im- plicit memory, and that the isolated left hemisphere can support nor- mal levels of visual priming in a variety of tasks.