Bubb, Emma J. ![]() ![]() Item availability restricted. |
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Abstract
The cingulum bundle is a highly complex fibre pathway that is implicated in a wide array of functions, yet little is known about its constituent connections and their differential contributions to cognition. This thesis investigated the dense interconnections between the cingulate cortices and the anterior thalamic nuclei, many of which join the cingulum. Initially, contemporary viral-based tract tracing techniques in the rat provided an anatomical reappraisal of this major component of the tract. This investigation revealed that many fibres between the anterior cingulate cortex and the anteromedial thalamic nucleus are present in the anterior cingulum, a subsection typically associated with executive function. Connections between the retrosplenial cortex and the anteroventral thalamic nucleus, meanwhile, primarily occupy the posterior cingulum, a subsection linked to memory. Next, this thesis investigated the role of anterior cingulate-anterior thalamic interconnectivity in attention. Existing evidence implicates both regions in intradimensional set-shifting, where discriminations are most effectively solved by responding to a stimulus dimension that previously predicted reward. A series of DREADDs manipulations confirmed that the anterior cingulate cortex supports this attentional function in rats, and novel evidence indicated that projections to the anterior thalamic nuclei critically contribute to this capacity. This thesis further found that in the absence of normal anterior cingulate function, inappropriate attention appears to be directed to unreliable reward predictors, facilitating performance when contingencies change (extradimensional shift). These findings are best explained by dual-process theories of attention where competing learning parameters, with distinct neural underpinnings, mediate the allocation of attentional resources. One process directs attention to reliable predictors of outcomes (reliant on the anterior cingulate cortex and its actions on the anterior thalamic nuclei), while another biases attention towards unreliable predictors of outcomes
Item Type: | Thesis (PhD) |
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Date Type: | Completion |
Status: | Unpublished |
Schools: | Schools > Psychology |
Subjects: | B Philosophy. Psychology. Religion > BF Psychology |
Date of First Compliant Deposit: | 7 May 2020 |
Date of Acceptance: | 5 May 2020 |
Last Modified: | 07 Nov 2022 10:12 |
URI: | https://orca.cardiff.ac.uk/id/eprint/131469 |
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