Focus: Behavioural Neuroscience
Thesis Advisors:Dr. Cheryl McCormick
For my dissertation, I have been using amphetamine to study the development of the dopamine system in adolescenct rats. Adolescents are at an increased risk for disorders associated with dysregulation of the dopamine system, including addiction, ADHD, and schizophrenia. One way of detecting functional differences in this system over development includes measuring differences in behavioural and neural respones to drugs that act as dopamine agonists or antagonists. Adolescent and adult rats differ in sensitivity to initial amphetamine treatment and exhibit more rapid alterations in behaviour after subsequent drug treatment, indicating that the developing dopamine system may be more malleable compared to adults. Increased malleability is further supported by evidence from our lab that exposure to chronic social stress in adolescence, but not in adulthood, enhances sensitivity to amphetamine in adulthood, indicating that ongoing maturation renders the adolescent dopamine system more susceptible to 'programming' effects. I am currently investigating the mechanisms that underlie age differences after initial and repeated treatment with amphetamine.
McCormick, C.M., & Mathews, I.Z. (submitted). Adolescent development, hypothalamic-pituitary-adrenal function, and programming of adult learning and memory. Progress in Neuro-Psychopharmacology & Biological Psychiatry.
McCormick, C.M., Mathews, I.Z., Thomas, C., & Waters, P.G. (in press). Investigations of HPA function and the enduring consequences of stressors in adolescence in animal models. Brain & Cognition.
Mathews, I.Z., Waters, P.G., & McCormick, C.M. (2009). Changes in hyporesponsiveness to acute amphetamine and age differences in tyrosine hydroxylase immunoreactivity in the brain over adolescence in male and female rats. Developmental Psychobiology, 51.
Mathews, I.Z., Wilton, A., Styles, A., & McCormick, C.M. (2008). Increased depressive behaviour in females and heightened corticosterone release in males to swim stress after adolescent social stress in rats. Behavioural Brain Research, 190, 33-40.
Mathews, I.Z., Mills, R., & McCormick, C.M. (2008). Chronic social stress in adolescence influenced both amphetamine conditioned place preference and locomotor sensitization. Developmental Psychobiology, 50, 451-459.
McCormick, C.M., Smith, C., & Mathews, I.Z. (2008). Effects of chronic social stress in adolescence on anxiety and neuroendocrine response to mild stress in male and female rats. Behavioural Brain Research, 187, 228-238.
Mathews, I.Z., & McCormick, C.M. (2007). Female and male rats in late adolescence differ from adults in amphetamine-induced locomotor activity, but not in conditioned place preference for amphetamine. Behavioural Pharmacology, 18, 641-50.
McCormick, C.M. & Mathews, I.Z. (2007). HPA function in adolescence: Role of sex hormones in its regulation and the enduring consequences of exposure to stressors. Pharmacology, Biochemistry, and Behavior, 86, 220-233.