Age-related changes in visual and motor functions : evaluating task activation and deactivation.

• Main Author: Seow, Esmond Lee Seng.
• Other Authors: School of Humanities and Social Sciences
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Social sciences
• Online Access: http://hdl.handle.net/10356/49126
• Institution: Nanyang Technological University

The current functional MRI study aimed to investigate age-related changes in basic visual and motor functions through activation and deactivation during a cognitive task. While numerous studies had looked into the same sensory processes, they tend to explore only the task activated regions. In an attempt to provide a more comprehensive understanding of aging effects, the study examined both the task positive networks in terms of activation and task negative network that focused on the default mode regions. In addition, the study employed two task paradigms, the checkerboard and gripping tasks that entail no age-related difficulty to minimize possible confound of task difficulty. ROIs analyses revealed younger subjects to have increased task activation for visual but not motor processing, and no age-related differences was observed for task induced deactivation within the default mode network. However, a whole brain exploratory analysis during the gripping task showed greater task activation for the younger subjects. This suggests that though age-related differences were not evident within the motor networks, the decrease in overall functional activation in the elderly may be showing an initial decline. Furthermore, activation and deactivation patterns in the two tasks between the young and elderly participants were not consistent with the PASA (posterior-anterior shift in aging) and HAROLD (hemispheric asymmetry reduction in older adults) models that seem to support the compensation process of aging. Taken together, our findings of functional decline provide evidence to indicate a dedifferentiation process of aging for basic visual and motor processing.