A perceptual-mnemonic role for the perirhinal cortex in age-associated cogntive decline

Persistent Link:
http://hdl.handle.net/10150/195350
Title:
A perceptual-mnemonic role for the perirhinal cortex in age-associated cogntive decline
Author:
Burke, Sara Nicole
Issue Date:
2009
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Perirhinal cortical-dependent behavior and single-unit neuron activity in this brain region were compared between normal aged and young rats. Three different variants of the spontaneous object recognition task were used in these experiments, and the results confirmed previous reports that aged animals are impaired at stimulus recognition. The novel contribution of the present experiments was the identification that the behavioral deficit in the aged rats was due to the old animals treating novel objects as familiar, rather than to forgetting the previously experienced stimuli. This pattern of results in the old animals mirror data obtained from rats with perirhinal cortical lesions and promotes a hypothesis that this area of the brain serves a perceptual-mnemonic function. Additionally, multiple single-unit recordings were obtained from perirhinal cortical cells while young and aged rats traversed a track that contained several objects. Perirhinal neurons exhibited selective increases in their firing rates at object locations. We have called these areas of higher perirhinal cortical cell activity `object fields'. While both young and old rats expressed object fields, a lower proportion of perirhinal neurons showed this type of activity in the aged compared to the young rats. Although familiar and novel objects were placed on the track as part of a systematic design, there was no effect of novelty on the overall firing rates of perirhinal cortical neurons or the proportion of cells expressing object fields under these experimental conditions. These data suggest that the physiological correlate of stimulus recognition is not decrements in perirhinal cortical activity when a stimulus goes from novel to familiar. A final important observation made during these studies in young rats was that place fields in the middle hippocampal CA1 subregion are affected by placing objects in the track. Because this same manipulation increases perirhinal cortical activity, it could indicate that age-related changes in the perirhinal cortex might alter the function of other closely associated structures.
Type:
text; Electronic Dissertation
Keywords:
aging; hippocampus; memory; object recognition; perception
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Neuroscience; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Barnes, Carol A.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleA perceptual-mnemonic role for the perirhinal cortex in age-associated cogntive declineen_US
dc.creatorBurke, Sara Nicoleen_US
dc.contributor.authorBurke, Sara Nicoleen_US
dc.date.issued2009en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractPerirhinal cortical-dependent behavior and single-unit neuron activity in this brain region were compared between normal aged and young rats. Three different variants of the spontaneous object recognition task were used in these experiments, and the results confirmed previous reports that aged animals are impaired at stimulus recognition. The novel contribution of the present experiments was the identification that the behavioral deficit in the aged rats was due to the old animals treating novel objects as familiar, rather than to forgetting the previously experienced stimuli. This pattern of results in the old animals mirror data obtained from rats with perirhinal cortical lesions and promotes a hypothesis that this area of the brain serves a perceptual-mnemonic function. Additionally, multiple single-unit recordings were obtained from perirhinal cortical cells while young and aged rats traversed a track that contained several objects. Perirhinal neurons exhibited selective increases in their firing rates at object locations. We have called these areas of higher perirhinal cortical cell activity `object fields'. While both young and old rats expressed object fields, a lower proportion of perirhinal neurons showed this type of activity in the aged compared to the young rats. Although familiar and novel objects were placed on the track as part of a systematic design, there was no effect of novelty on the overall firing rates of perirhinal cortical neurons or the proportion of cells expressing object fields under these experimental conditions. These data suggest that the physiological correlate of stimulus recognition is not decrements in perirhinal cortical activity when a stimulus goes from novel to familiar. A final important observation made during these studies in young rats was that place fields in the middle hippocampal CA1 subregion are affected by placing objects in the track. Because this same manipulation increases perirhinal cortical activity, it could indicate that age-related changes in the perirhinal cortex might alter the function of other closely associated structures.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectagingen_US
dc.subjecthippocampusen_US
dc.subjectmemoryen_US
dc.subjectobject recognitionen_US
dc.subjectperceptionen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineNeuroscienceen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorBarnes, Carol A.en_US
dc.contributor.committeememberRyan, Leeen_US
dc.contributor.committeememberNadel, Lynnen_US
dc.contributor.committeememberBurwell, Rebeccaen_US
dc.identifier.proquest10402en_US
dc.identifier.oclc659752021en_US
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