The role of the anterior thalamic nuclei for properties of episodic memory: what, when, where
Year: 2012
Type: dissertation
Abstract: Amnesia impairs episodic memory in humans, and can occur following damage to \nthe medial diencephalon. This thesis examines the importance of the anterior \nthalamic nuclei, a diencephalic structure, for different elements (what, when, \nwhere) of episodic memory (or episodic-like memory) in rats. The overall goal was \nto understand why this region is so critical for normal memory in humans. An \ninitial series of experiments investigated the ability of rats with anterior thalamic \nlesions to recognise objects and odours with a variety of delays. These \nexperiments found that anterior thalamic lesions spare item recognition (what). \nThis same ability was further explored with the use of the immediate early gene \nzif268, and the results again indicated that this thalamic nucleus does not have a \ndirect role in recognition. A related series of studies explored the effects of \nanterior thalamic lesions on temporal order judgments (when) for objects. Two \ndifferent discrimination procedures were tested, between-block recency and \nwithin-block recency. Lesions to the anterior thalamic nuclei selectively impaired \nperformance on within-block recency but spared between-block recency. The \nability of rats with anterior thalamic damage to discriminate between two \nlocations (where) in both complex and simple environments was also tested. \nAnterior thalamic lesions significantly impaired place learning compared with \ncontrol animals, despite the finding that rats with anterior thalamic lesions could \nsometimes discriminate between the two locations (i.e., could perform \nsignificantly above chance). In addition, the effects of anterior thalamic damage on \nbiconditional learning (what-where conjunction) were examined. The rats were \ntrained on both item-place and item-context associations. Lesions to the anterior \nthalamic nuclei disrupted acquisition of the former, but not the latter. The results \nsuggest that the contributions of the rodent anterior thalamic nuclei to episodic \nmemory, as part of the extended-hippocampal system, primarily reflect the \ninvolvement of these nuclei in allocentric spatial learning.
Author: Julie R. Dumont
Language: Spanish
Topic: Memory and Neural Mechanisms
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1823015635