La relation entre la stratégie de navigation spontanée et la prise de décision et les fonctions exécutives
When people navigate, they use one of two strategies. The hippocampus-based spatial strategy consists of using multiple landmarks in order to create a mental map of the environment. In contrast, caudate nucleus-based response strategy is based on the memorization of a rigid series of turns. Importantly, response learners display more grey matter and functional activity in the caudate and less grey matter in the hippocampus. The caudate is a structure central to the reward circuit, while the hippocampus supports spatial and episodic memory. The goal of the present thesis was to better understand the implications of spontaneous navigational strategies over cognitive functioning. To this end, we recruited 53 young adults, separated in two groups based on the strategy used in the 4 on 8 virtual maze. We compared both groups over decision-making (Iowa Gambling Task (IGT) and Columbia Card Task (CCT)), task-switching, working memory (digit span test) and cognitive flexibility (Wisconsin Card Sorting Test-64 (WCST-64)) task performances. This thesis shows that response learners display enhanced executive functioning in the WCST-64, task-switching test and digit span test through reduced perseveration errors, reduces switch cost and increased digit span length respectively. Increased risk-taking behaviour was observed in the IGT. These results support the theory that caudate nucleus mediates much of the executive functioning through mesocortical dopamine pathways. They also allow us to better understand the impact of spontaneous navigational strategies on the cognitive health of young adults, allowing for the developement of interventions aiming at strengthening certain cognitive functions.
Iowa Gambling Task Wisconsin Card Sorting Test Navigation Caudate nucleus Executive functions Cognitive flexibility Decision-making Caudate nucleus Hippocampus Risk-taking