Brenda J. Anderson

Research ACtivities: My lab is interested in understanding the biological basis for the effects of exercise and stress on mental health and cognition. I use voluntary and forced exercise in rats as a model for the effects of exercise on humans. I use corticosterone injections to mimic the effects of stress. My students and I use three general approaches toward our goals: behavioral analysis, quantitative anatomy, and quantitative histochemistry.

Behavioral approaches are used to establish effects of exercise on subsequent behavior in rats. Using the radial arm maze and the Barnes maze, we have tested whether exercise improves spatial memory. Using the Barnes maze and the Y-maze we have tested whether the stress-related hormone corticosterone impairs spatial memory (Coburn-Litvak et al., 2003). We have also tested whether corticosterone administered over long periods alters activity, exploration (Tata et al., submitted), anxiety, and anhedonia (Gorby et al., in preparation).

Quantitative anatomical analyses are used to determine whether or not exercise and stress-related hormones have an influence on capillary density, tissue volume and synaptic numbers in the brain. All of these variables would be expected to influence brain function and vulnerability. For example, we have recently shown that two-month administration of the stress-related hormone corticosterone (40 mg/kg) causes neuropil volume reduction and synapse loss in hippocampal area CA3 (Tata et al., in preparation).

Moderate doses given for 2 months causes a loss of mitochondrial volume fraction (Coburn-Litvak et al., 2004) and high doses cause a reduction in glial and mitochondrial volume (Tata et al., in preparation).

Quantitative histochemical analyses are used to investigate the possibility that the brain undergoes metabolic plasticity after chronic exercise or stress. We are currently testing whether chronic administration of corticosterone causes a reduction in bioenergetic capacity. If so, the results would suggest that long-term elevations in stress-related hormones would leave the hippocampus more vulnerable to metabolic challenge (e.g., excitotoxicity and ischemia).

We have also shown that exercise increases bioenergetic capacity (cytochrome oxidase activity) in the motor cortex and dorsolateral striatum (McCloskey, Adamo, and Anderson, 2001). We are currently investigating whether exercise provides protection from excitotoxicity.

Our findings have implications for the impact that lifestyle choices have on brainaging.

Previous experience with fMRI