Neuroscience 2002 Abstract
| Presentation Number: | 678.6 |
|---|---|
| Abstract Title: | age-related changes in hippocampal map realignment. |
| Authors: |
Rosenzweig, E. S.*1
; Redish, A. D.1,2
; McNaughton, B. L.1
; Barnes, C. A.1
1NSMA, U of A, Tucson, AZ 2Neuroscience, U of M, Minneapolis, MN |
| Primary Theme and Topics |
Cognition and Behavior - Animal Cognition and Behavior -- Learning & memory: Physiology and imaging |
| Session: |
678. Animal cognition and behavior: learning and memory--physiology and imaging: hippocampus and neocortex Poster |
| Presentation Time: | Wednesday, November 6, 2002 9:00 AM-10:00 AM |
| Location: | Hall A2-B3 Q-3 |
| Keywords: | PLACE CELLS, AGING, PATH INTEGRATION, HIPPOCAMPUS |
It has been suggested that the strongest initial determinant of rat place-cell firing is internally-generated information about the rat’s motion relative to a known starting point, and that experience in an environment is required for cues and landmarks to gain control over place-cell firing. This associative binding of cues to an ensemble of hippocampal neurons (a ‘map’) may involve LTP. Because LTP is impaired in aged rats, cues should be poorly bound to their hippocampal maps.
To test this prediction, aged and adult rats were trained on a linear track task with a mobile start box (c.f. Gothard et al., 1996) in which self-motion and visual-cue information are mismatched across trials. Self-motion controls place-cell firing during the initial portion of each journey, then the hippocampal map realigns so that visual cues control place-cell firing during the latter portion of the journey. As predicted, this realignment was delayed in aged rats, occurring nearer to the end of the track. Moreover, the realignment delay was correlated with the rats’ ability to find a hidden goal at a position fixed relative to distal visual cues. The results suggest that some of the spatial-learning deficits observed in aged rats may be due to impaired binding of cues to the hippocampal map.
In addition, despite the fact that animals in the present study had never been trained with a stable start box (the anchor point for self-motion), place-cell firing was controlled by self-motion information for a large portion of each outbound journey. This second result supports a strong initial role of self-motion information in determining the configuration of place-cell firing in an environment.
To test this prediction, aged and adult rats were trained on a linear track task with a mobile start box (c.f. Gothard et al., 1996) in which self-motion and visual-cue information are mismatched across trials. Self-motion controls place-cell firing during the initial portion of each journey, then the hippocampal map realigns so that visual cues control place-cell firing during the latter portion of the journey. As predicted, this realignment was delayed in aged rats, occurring nearer to the end of the track. Moreover, the realignment delay was correlated with the rats’ ability to find a hidden goal at a position fixed relative to distal visual cues. The results suggest that some of the spatial-learning deficits observed in aged rats may be due to impaired binding of cues to the hippocampal map.
In addition, despite the fact that animals in the present study had never been trained with a stable start box (the anchor point for self-motion), place-cell firing was controlled by self-motion information for a large portion of each outbound journey. This second result supports a strong initial role of self-motion information in determining the configuration of place-cell firing in an environment.
Supported by MH01565, AG12609, AG05805.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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