Altered medial temporal lobe responses during visuospatial encoding in healthy APOE*4 carriers.

Full Abstract

The apolipoprotein varepsilon4 allele (APOE*4) is a major genetic risk factor for Alzheimer's disease (AD) and has been associated with altered cortical activation as assessed by functional neuroimaging in cognitively normal younger and older carriers. We chose to evaluate medial temporal lobe (MTL) activation during encoding and recognition using a perspective-dependent (route or survey) visuospatial memory task by monitoring the blood-oxygen-level-dependent (BOLD) fMRI response in older, non-demented APOE*4 carriers (APOE*4+) and non-carriers (APOE*4-). During encoding, the APOE*4- group had greater average task-associated BOLD responses in ventral visual pathways, including the MTLs, as compared to the APOE*4+ group. Furthermore, MTL activation was greater during route encoding than survey encoding on average in APOE*4-, but not APOE*4+, subjects. During recognition, both groups performed similarly and no BOLD signal differences were found. Finally, within-group analysis revealed MTL activation during encoding was correlated with recognition performance in APOE*4-, but not APOE*4+ subjects. Reduced task-associated MTL activation that does not correlate with either visuospatial perspective or task performance suggests that MTL dysregulation occurs prior to clinical symptoms of dementia in APOE*4 carriers.

Learn Faster Today Improve your study skills

Author information

Author/s: Borghesani, Paul R (PR); Johnson, L Clark (LC); Shelton, Amy L (AL); Peskind, Elaine R (ER); Aylward, Elizabeth H (EH); Schellenberg, Gerard D (GD); Cherrier, Monique M (MM);

Affiliation: Mental Illness Research, Education, and Clinical Center (MIRECC), Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA. paulrb(-atsign-)u.washington.edu

Grants: AGO0258 (Agency:PHS HHS) ; AGO5136 (Agency:PHS HHS) ; P50 AG05136 (Agency:NIA NIH HHS) ; T32 AG00258 (Agency:NIA NIH HHS)

Journal and publication information

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

Journal: Neurobiology of aging (Neurobiol Aging), published in United States. (Language: eng)

Reference: 2008-Jul; vol 29 (issue 7) : pp 981-91

Dates: Created 2008/05/26; Completed 2008/06/20;

PMID: 17350142, status: MEDLINE (last retrieval date: 12/26/2008)

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

External Links for this article (including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.

MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adaptation, Physiological - physiology
Aged
Apolipoprotein E4 - genetics
Evoked Potentials, Visual - physiology
Female
Heterozygote

Humans
Male
Mental Recall - physiology
Reference Values
Space Perception - physiology
Temporal Lobe - physiology

Associated Chemicals: Apolipoprotein E4 (0)

These are the highest related articles currently in the database:

See 100+ related articles.