This thesis examines how brain structure and connectivity are associated with decision-making under uncertainty. Previous evidence suggests that during uncertain tasks, where there is no known optimal decision process, individuals will update decision-making behaviour on a trial-by-trial basis that is dependent on the outcomes of previous choices. Win-stay, lose-shift is an example of a strategy that individuals will use to maximise rewards and minimise losses. Using voxel-based morphometry and tract-based spatial statistics, I initially explored how brain structure was associated with win-stay, lose-shift behaviour. The results showed that lose-shift behaviour was significantly associated with reduced grey matter volume in temporal and occipital regions, increased white matter volume in the superior temporal gyrus, and reduced global fractional anisotropy. Interestingly, I found an association between lose-shift behaviour and grey matter volume within occipital cortex which was largely unexpected. To further explore this relationship, I used transcranial Direct Current Stimulation (tDCS) to modulate activity within the cuneus during an uncertain decision paradigm without loss incentives. It was found that tDCS had no effect on decision- making under uncertainty. This further suggested that the occipital cortex may be associated specifically with lose-shift behaviour under uncertainty. Finally, we conducted resting-state functional connectivity analyses to understand the underlying functional connectivity associated with win-stay, lose-shift behaviour. This provided further evidence that the occipital cortex may be uniquely associated with lose-shift behaviour during uncertain decision tasks. In summary, the results from these studies provide further evidence that the occipital cortex is associated with decision-making behaviour following loss outcomes. This research furthers understanding of the neural and behavioural components of decision-making processes following loss outcomes which may have implications for the treatment of disorders in which reward and loss-based decision-making is implicated.
| Date of Award | 2 Jul 2024 |
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| Original language | English |
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| Supervisor | Chris Retzler (Main Supervisor), Glyn Hallam (Co-Supervisor) & Holly Brown (Co-Supervisor) |
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