The Open UniversitySkip to content
 

An examination of the effects of thalamic lesions on learning and memory in the rat

Hunt, Peter Richard (2000). An examination of the effects of thalamic lesions on learning and memory in the rat. PhD thesis The Open University.

Full text available as:
[img]
Preview
PDF (Version of Record) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (13MB) | Preview
Google Scholar: Look up in Google Scholar

Abstract

The study examined the effects of lesions of the thalamic nucleus medialis dorsalis (MD) made by neurotoxin in three cohorts ofrats to help understand the contribution of this nucleus to learning and memory. The lesions typically provided comprehensive damage to . MD, while the use of an excitotoxin helped to minimise damage to fibres of passage or adjacent fibre tracts. This excluded one confounding influence that may have been present in some previous studies. Some MD lesions also affected the anterior thalamic nuclei, and this additional damage led to spatial memory impairments, helping to confirm the value of results from rats with lesions confined to MD. Whilst the groups with MD lesions were largely unimpaired on non-spatial tests of visual recognition and discrimination, they were impaired on a configural discrimination task. The MD lesions did not impair spatial nonmatching to sample in aT-maze, nor the acquisition or performance over delay conditions of the standard radial maze task. There were impairments, however, when the radial maze was rotated during the delay, requiring a strategy shift. Similar impairment was found when a matching, rather than non-matching, strategy was required on the T-maze task and also when only some arms were rewarded on the radial arm maze task for reference memory measurement. No impairment was seen when the T-maze matching task was reversed to the non-matching variant, emphasising the lesion rats' preference for preexisting rules. In addition, some evidence was found that MD lesions brought about increased activity, but had no effect on conditioned place preference. The study concludes that MD damage in rats does not directly cause memory deficits. The influence that MD damage has on memory is, however, similar to that associated with damage to prefrontal cortex causing deficits in rule-switching ability, a higher order frontal lobe function .

Item Type: Thesis (PhD)
Copyright Holders: 2000 The Author
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 58058
Depositing User: ORO Import
Date Deposited: 30 Nov 2018 09:45
Last Modified: 09 Jul 2019 20:05
URI: http://oro.open.ac.uk/id/eprint/58058
Share this page:

Download history for this item

These details should be considered as only a guide to the number of downloads performed manually. Algorithmic methods have been applied in an attempt to remove automated downloads from the displayed statistics but no guarantee can be made as to the accuracy of the figures.

Actions (login may be required)

Policies | Disclaimer

© The Open University   contact the OU