Experience-dependent eye movements, awareness, and hippocampus-dependent memory.

Full Abstract

We asked what kind of memory is operating when eye movements change as the result of experience. Participants viewed scenes that were either novel, repeated, or manipulated (i.e., a change was introduced in one region of the scene). Eye movements differed depending on the past viewing history of each scene. Participants made fewer fixations and sampled fewer regions when scenes were repeated than when scenes were novel. When scenes were altered, participants made more fixations in the altered region, spent more time looking at the altered region, and made more transitions into and out of the altered region than in unchanged (matched) regions in the repeated scenes. Importantly, these effects occurred only when individuals were aware that a change had occurred. Participants who were unaware that the scene had been altered looked at the changed scenes in the same way that they looked at repeated scenes. Thus, there was no indication that eye movements could reveal an unaware (unconscious) form of memory. Instead, eye movements reflected conscious memory of whether the scene was repeated or manipulated. The findings were the same when awareness was assessed after viewing all the scenes (experiment 1) and when awareness was assessed after each scene was presented (experiment 2). In experiment 3, memory-impaired patients with damage limited to the hippocampus were impaired at deciding whether scenes were novel, repeated, or manipulated. Thus, the ability to consciously recollect recent encounters with scenes reflects a form of hippocampus-dependent memory. The findings show that experience-dependent eye movements in response to altered scenes reflect conscious, declarative memory, and they support the link between aware memory, declarative memory, and hippocampus-dependent memory.

Author information

Author/s: Smith, Christine N (CN); Hopkins, Ramona O (RO); Squire, Larry R (LR);

Affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, California 92093, USA.

Grants: 5-T32-AG00216 (Agency:NIA NIH HHS) ; 5-T32-MH20002 (Agency:NIMH NIH HHS) ; MH24600 (Agency:NIMH NIH HHS) ; R01 MH024600-33 (Agency:NIMH NIH HHS)

Journal and publication information

Publication Type: Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.

Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci), published in United States. (Language: eng)

Reference: 2006-Nov; vol 26 (issue 44) : pp 11304-12

Dates: Created 2006/11/02; Completed 2006/11/14; Revised 2009/01/15;

PMID: 17079658, status: MEDLINE (last retrieved date: 2/18/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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