Neuroscience 2000 Abstract
| Presentation Number: | 171.15 |
|---|---|
| Abstract Title: | Hippocampal lesions reverse a learned irrelevance-type effect in a signaled appetitive operant task. |
| Authors: |
Miller, D. P.*1,2
; Doherty, T. M.1
; Allen, M. T.3
1Dept. of Psyc., Carthage College, Kenosha, WI 2Prog. in Neuro., Carthage College, Kenosha, WI 3Center for Mol. and Beh. Neuro., Rutgers Univ., Newark, NJ |
| Primary Theme and Topics |
I. Neural Basis of Behavior - 107. Learning and memory: systems and functions-animals |
| Session: |
171. Learning and memory: systems and functions--hippocampus: spatial and nonspatial learning and memory Poster |
| Presentation Time: | Sunday, November 5, 2000 3:00 PM-4:00 PM |
| Location: | Hall G-J |
| Keywords: | hippocampus, non spatial, barpressing, instrumental |
A retardation in learning following explicitly uncorrelated presentations of a CS and US has been described as a learned irrelevance effect (e.g., Baker & MacKintosh, Animal Learn & Beh, 5:315, 1977). We reported a learned irrelevance-type effect in appetitive signaled barpressing (D. P. Miller, H. N. Kersten, T. M. Doherty, & J. L. Crouch, SFN Abstracts, 1999). Rats were trained to receive food pellets on a FR-8 partial reinforcement schedule. A group that received 100 pre-exposures to a 1 sec tone/d for 10 d while performing the FR-8 task showed a significant delay in learning a subsequent task that required a barpress during the 1 sec tone period to receive reinforcement. Thus the initial presentations of the tone uncorrelated with the rats' barpress behavior appeared to inhibit subsequent learning when the tone became the only relevant stimulus for obtaining reinforcement. Allen and Gluck (SFN Abstracts, 1997) reported that lesions of the dorsal hippocampus disrupted the learned irrelevance-related retardation observed in rabbit eyeblink conditioning. We have demonstrated the same effect in the signaled barpress paradigm. Rats with lesions of the dorsal hippocampus demonstrated no retardation of the signaled barpress response following tone pre-exposure uncorrelated with performance on the FR-8 task. These data suggest that the retardation in learning that we have observed is dependent on the function of the hippocampus and related structures and may be a function of the same underlying mechanisms that produce the learned irrelevance effect in classical conditioning.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2000 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2000. Online.
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