Neuroscience 2001 Abstract
| Presentation Number: | 642.6 |
|---|---|
| Abstract Title: | LEARNED IRRELEVANCE EFFECT DIMINISHED BY DELAY FOLLOWING PRE-EXPOSURE AFFECTS COMPARISON WITH HIPPOCAMPAL LESIONED RATS DURING SIGNALED BARPRESSING. |
| Authors: |
Chapleau, C. A.*1,2,3
; Crosby, K. M.4
; Miller, D. P.1,2
1Neuroscience, Carthage College, Kenosha, WI 2Psychology, Carthage College, Kenosha, WI 3Biology, Carthage College, Kenosha, WI 4Physics, Carthage College, Kenosha, WI |
| Primary Theme and Topics |
Cognition and Behavior - Animal Cognition and Behavior -- Associative, nonassociative and skill learning & memory systems |
| Secondary Theme and Topics | Cognition and Behavior<br />- Animal Cognition and Behavior<br />-- Cognitive learning and memory systems |
| Session: |
642. Animal cognition and behavior: associative, nonassociative and skill learning and memory systems--conditioning and nonassociative learning Poster |
| Presentation Time: | Tuesday, November 13, 2001 2:00 PM-3:00 PM |
| Location: | Exhibit Hall TT-30 |
| Keywords: | HIPPOCAMPUS, NON SPATIAL, MODEL, ENTORHINAL CORTEX |
Previously we reported a learned irrelevance-type retardation in appetitive signaled barpressing (SBP) that appeared to be dependent on the hippocampus and associated cortical structures (Miller, Doherty, Chapleau, & Allen, SFN Abstracts, 2000). Rats receiving hippocampal lesions followed by 10 d of 100 pre-exposures/d to a 1 sec tone that was uncorrelated with performance on a FR-8 reinforcement schedule showed a significant delay in learning to press a bar during the 1 sec tone presentation for food pellet reinforcement. This retardation was reversed in rats with non-selective hippocampal lesions. Allen and Gluck (SFN Abstracts, 1998) demonstrated that selective lesions of the entorhinal cortex but not the hippocampus abolished learned irrelevance in rabbit eyelid conditioning. In the current study we delivered the pre-exposure sessions prior to performing hippocampal lesions followed by SBP training after recovery from surgery. We hypothesized that tone pre-exposure with the hippocampus intact would allow a representation of the tone irrelevancy to be formed in associated cortical areas that would not be disrupted by hippocampal lesions. We found that a non-surgery control group that experienced a 10 d delay between tone pre-exposure and SBP conditioning showed a reduction in learned irrelevance-related inhibition. We developed a mathematical model of signaled barpressing that is based on the difference between the values of the tone representation and context. We suggest that learned irrelevance-related plasticity is a function of the quantity and timing of pre-exposure in relation to conditioning.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2001 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2001. Online.
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