| Variability in hippocampal volume is observed across the adult lifespan. However, relatively little is known about the relationship between hippocampus volume and its function. Hippocampus functions include novelty processing and episodic memory. The current dissertation sought to determine if there is a relationship between hippocampus volume and these neural processes. Manual tracing of high resolution MR brain images were used to analyze hippocampus volume. Firstly a hippocampus volume and novelty seeking association was investigated. MRIs and a validated experience seeking personality scale, measuring one's natural tendency to seek novel stimuli, were collected from a group of healthy young adults. Hippocampus volume was then correlated with scores on the experience seeking scale. Results revealed a positive correlation between right hippocampal volume and scores on the experience seeking scale. I then sought to determine whether hippocampus volume is linked to future episodic memory impairment in seniors destined to develop mild cognitive impairment (pMCI). Results indicate that hippocampus volume is reduced in pMCI participants compared to senior adults who remained normal. Furthermore, results showed an anterior to posterior volume gradient, wherein the anterior portion (head) of the hippocampus showed the greatest volumetric difference followed by the middle portion (body) and then the posterior portion (tail), which showed no difference between the two groups. Collectively, the current dissertation demonstrates a relationship between hippocampus volume and processes previously linked with hippocampus function.;Key words. Hippocampus, Experience Seeking, Presymptomatic Mild Cognitive Impairment, Alzheimer's Disease, Structural Magnetic Resonance Imaging. |
