First Name:
Grant
Last Name:
Canipe
Major Department:
Psychology
Thesis Director:
Amy Knab
Date of Thesis:
May 2013
The dopamine system, which regulates motor movement, motivation, reward, and emotions, is linked to physical activity behavior in mice. It has also been discovered that enrichment - physical activity - and the dopamine system may be linked to an increase in cognitive functioning especially in those who suffer with cognitive impairments due to disease or stroke. Environmental factors such as nutrition can affect the dopamine system. “Caloric restriction” has been shown to induce changes in key neuromodulators in the brain, leading to increased longevity and better health. The key neuroregulatory molecules that may play a role in regulating physical activity include: regulatory enzyme sirtuin 1 (sirt1) found in metabolically important brain regions, and brain derived neurotrophic factor (bdnf), a molecule important in neuronal plasticity, as well as several dopaminergic receptors including drd1. It is proposed that these key molecular targets act centrally (in the brain), to regulate physical activity behavior in response to caloric restriction, and as a result these gene expression changes may be linked to an increase in cognitive functioning. This study was the first to investigate the potential synergistic effects of CR and physical activity of dopaminergic, and neurotrophic signaling expression patterns in the brain. The level of CR used in the current study was not sufficient to induce genetic expression differences in sirt1 ordrd1; however, bdnf signaling was significantly affected by CR regardless of wheel running exposure. This suggests that moderate CR has a larger impact on brain signaling than wheel running alone. Whether CR could be used as an environmental influence to increase motivation for physical activity, through genetic expression changes in certain areas of the brain, remains to be fully elucidated. Future research should focus on the level of CR needed, as well as investigate different areas of the brain including the hippocampus.