Psychology ETDs

Publication Date

Fall 11-9-2016

Abstract

Previous studies have shown that the anterior thalamic nuclei (ATN) contain a large population of head direction cells, which fire as a function of an animal’s directional orientation in an environment, thereby providing a compass-like representation guiding navigation. Recent work has suggested that directional orientation information stemming from the ATN is critical for the generation of hippocampal and parahippocampal spatial representations, and may contribute to the establishment of unique spatial representations in radially oriented tasks such as the radial arm maze. While studies have confirmed that ATN lesions impair the acquisition of new spatial information in variants of the radial maze, few have attempted to dissociate its unique contributions to acquisition vs. retrieval and spatial reference vs working memory in radial tasks. Here, we addressed these questions by training rats in a radial arm maze procedure to asymptotic levels, and after 24hrs, animals were administered muscimol inactivation of the ATN before a 4 trial probe test. We report impairments in retrieval of both spatial reference and working memory, suggesting a general absence of improved navigation across post-inactivation training trials. Taken together, the results above suggest that the ATN modulates the retrieval of previously acquired allocentric spatial information in the radial-arm maze, but also suggests a critical role in the online guidance of accurate spatial behavior. The results are discussed in relation to the thalamo-cortical circuits involved in spatial information processing.

Degree Name

Psychology

Level of Degree

Masters

Department Name

Psychology

First Committee Member (Chair)

Benjamin J. Clark

Second Committee Member

Nathan S. Pentkowski

Third Committee Member

Jonathan Brigman

Keywords

navigation, head direction, spatial, limbic, hippocampus

Document Type

Thesis

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