A multimodal investigation of retrosplenial function

Milczarek, Michal 2017. A multimodal investigation of retrosplenial function. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

The retrosplenial cortex (RSC) has attracted much attention due to its proposed role in learning and memory. It forms a part of the Papez circuit and is connected with the anterior thalamic nuclei, the hippocampal formation and sensory areas including the visual cortex. Damage to the RSC impairs episodic and spatial memory. Furthermore, dementias such as Alzheimer's Disease have been shown to involve retrosplenial pathology, highlighting the need to better understand the role of this region. The current work explores the contributions of the RSC to visual and spatial processing as well as its vulnerability in a model of amnesia. It is demonstrated here that visual stimulation of anaesthetised mice elicits intrinsic signal responses in the RSC, similar to those seen in the primary visual cortex. Further, it is shown that training on a spatial memory task is paralleled by the gradual formation of a context-specific retrosplenial memory engram, which re-activates upon re-exposure to the task weeks from initial acquisition. Moreover, the overall level of retrosplenial activity and the stability of the engram show a link to the successful expression of spatial memory upon re-exposure to the task. Finally, it is revealed that the disconnection of the mammillary bodies from the anterior thalamus, which is a common feature of diencephalic amnesia, leads to the reduction of the metabolic marker, cytochrome oxidase, in the RSC as well as to widespread microstructural changes revealed by diffusion tensor imaging. Taken together, it is demonstrated here that the RSC is an important integratory hub contributing to the formation of episodic memory and aspects of visual processing and that it displays high sensitivity to the loss of its inputs, which may explain its involvement in a variety of conditions.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Psychology
Subjects:	B Philosophy. Psychology. Religion > BF Psychology
Funders:	Wellcome Trust
Date of First Compliant Deposit:	19 March 2018
Last Modified:	17 Nov 2021 15:36
URI:	https://orca.cardiff.ac.uk/id/eprint/109976

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