Neuroscience 2005 Abstract
| Presentation Number: | 313.3 |
|---|---|
| Abstract Title: | Exposure to menopausal hormone therapy increases right hippocampal activation on a functional MRI verbal encoding task. |
| Authors: |
Gleason, C. E.*1,2
; Trivedi, M.1
; Schmitz, T. W.1
; Ries, M.1
; Asthana, S.1,2
; Johnson, S. C.1,2
1Medicine, Univ. of Wisconsin, Madision, WI 2Section of Geriatrics & Geronotology, Univ. of Wisconsin, Madision, WI |
| Primary Theme and Topics |
Cognition and Behavior - Human Cognition, Behavior, and Anatomy -- Learning and long-term memory |
| Secondary Theme and Topics | Techniques in Neuroscience<br />- Staining, Tracing, and Imaging Techniques |
| Session: |
313. Learning and Long-Term Memory II Poster |
| Presentation Time: | Sunday, November 13, 2005 3:00 PM-4:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # PP7 |
| Keywords: | HORMONE, FMRI, HIPPOCAMPUS, MEMORY |
Given estrogen's well-established neuroprotective effects, the dramatic decline in circulating estrogen occurring at menopause could result in deleterious neurobiological and cognitive effects. It is reasonable to expect that replacing estrogen with menopausal hormone therapies (MHTs) would impart neuroprotection and cognitive benefits. Indeed, many have documented a reduced risk for dementia with use of MHT. In contrast, the Women's Health Initiative Memory Study (WHIMS) revealed an increased risk for cognitive decline and dementia with conjugated equine estrogen therapies (i.e. Premarin® and Prempro®). Several theories have emerged attempting to explain these surprising data, such as the necessity of early, rather than late postmenopausal exposure to MHT. We used functional MRI methodology to examine the effects of early MHT, comparing 11 women exposed to MHT to 7 women naïve to MHT. The groups did not differ in age or education. Average age when women started MHT was 49.7 years (3.3), and mean years of use was 6.5 years (4.8). Prior studies have shown that encoding novel stimuli produces increased hippocampal BOLD signal (i.e. activation) compared to recall of previously learned material (novel v. familiar task). The MHT-exposed women demonstrated increased activation in the right hippocampus compared to MHT naïve women on our novel v. familiar fMRI task (x,y,z; 26,-36,-6; t=3.09, p=0.004). Whole brain analysis also revealed increased activation in the right caudate for MHT exposed versus MHT naïve women (x,y,z; 12,10,-8; t=4.72, p<0.000). These data suggest that MHT may alter neural substrate underlying verbal encoding. In contrast to MHT naïve subjects, MHT exposed women may recruit additional neurosystems when encoding information. The cognitive effects of these hypothesized organizational changes need further exploration.
Supported by NIA/NIH grants K23AG02430201 & R01AG02115501
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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