Effects of ‘everyday life stresses’ on behavior and health.
Dr. Cameron’s laboratory studies the effect of exposure to mild, everyday stresses on long-term health. Studies focus on identifying the neural systems which respond to stress and understanding how changes in the functional activity of these systems modulate stress-responsive physiological systems, including behavior, neuroendocrine function, body weight, cognitive function, attention, and motivation. The stresses studied include metabolic stresses (such as dieting, missing meals, and exercise), and psychosocial stress (such as being separated from familiar individuals and introduced to unfamiliar individuals). Studies utilize nonhuman primates, and many studies combine clinical work with experimental work to understand both the mechanisms underlying responses to chronic stress exposure, as well as the clinical implications of such stress exposure.
Experimental approaches include in vivo physiological studies monitoring behavior, hormone secretion, heart rate, metabolic substrates, neurotransmitter release and pharmacological studies. Collaborative work with several other laboratories allows histochemical examination of neural systems modulated by stresses using microarray analysis followed by in situ hybridization to identify changes in neuronal gene expression.
Current studies in the laboratory focus on three research questions. In the first area, the laboratory is continuing its long history of examining the effects of various stresses on fertility. The lab has developed measures to identify stress-sensitive and stress-resilient individuals and has started to characterize physiological characteristics associated with stress sensitivity and identify neural mechanisms underlying differences in stress sensitivity. The second area of interest is examination of how genetic predisposition for affective disorders interacts with environmental influences (stress exposure in early development) to lead to an increase in the incidence of anxiety and depression in adulthood. Experiments are identifying physiological traits that are associated with a predisposition to develop affective disorders and are examining changes in neural function in early development that may account for the later development of behavioral pathologies. The lab is also undertaking a large-scale linkage analysis to identify genes underlying the development of anxious behaviors. The third area currently being investigated is the effects of exercise and physical activity on the brain. These studies have shown that an amount of exercise that doctors recommend for middle-aged people wishing to improve health leads to increased blood flow to the brain, an increase in neurogenesis in the hippocampus and an increase in gliogenesis in many brain regions, along with an increase in alertness and attention. Current studies are examining whether exercise is neuroprotective against brain injury and neurodegenerative diseases.
Sullivan, E.L., and Cameron, J.L. A rapidly occurring compensatory decrease in physical activity counteracts diet-induced weight loss in female monkeys. American Journal of Physiology: Regulatory, Integrative and Comparative Section 298: 1068-1074, 2010. PMID: 20071608.
Rhyu, I.J., Bytheway, J.A., Kohler, S.J., Lange, H., Lee, K.J., Boklewski, J., McCormick, K., Williams, N.I., Stanton, G.B. Greenough, W.T., and Cameron, J.L. Effects of aerobic exercise training on cognitive function and cortical vascularity in monkeys. Neuroscience 167: 1239-1248, 2010. PMID: 20211699.
Knudsen, E.I., Heckman, J.J., Cameron, J.L., and Shonkoff, J.P. Building America’s Future Workforce: Economic, Neurobiological and Behavioral Perspectives on Investment in Human Skill Development. Proceedings of National Academy of Science 103: 10155-10162, 2006.