Reconsideration of the role of the hippocampus in learning inhibition: An integrative approach toward anatomical specificity and conceptual specificity
Abstract
The purpose of the present study is to reconsider the role of the hippocampus in learning and memory based on some advances in neuroscience techniques and a better understanding of inhibitory learning. It has recently been shown that under some conditions, the same cue can be embedded in simultaneous inhibitory and excitatory associations. Several experiments were designed to further investigate whether the hippocampus is involved in learning inhibitory associations to cues that are already embedded in excitatory associations. Experiment 1 provided evidence that argue against the notion that hippocampal-lesioned rats are generally hyperactive. Experiment 2 showed that hippocampal-lesioned rats exhibit increased net excitation relative to controls to the second order stimulus in second-order conditioning. Experiment 3 demonstrated that hippocampal-related deficits in Pavlovian conditioning to contextual stimuli depend on the opportunity to learn extinction to context cues. Experiment 4.1 replicated the finding that the hippocampus is not essential for learning conditioned inhibition; but also showed that lesions may have an impact on the amount or type of inhibition learned during conditioned inhibition training. Experiments 4.2 and 4.3 also supported that the hippocampus has a role in the acquisition of serial feature-negative discrimination under certain circumstances. These results support the notion that the hippocampus is involved in learning inhibitory associations to a cue that is already embedded in an excitatory association.
Degree
Ph.D.
Advisors
Davidson, Purdue University.
Subject Area
Neurology|Behaviorial sciences
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.