Dr. Shimon Amir, Concordia University
Circadian clocks are biological pacemakers that generate daily oscillations in a variety of biological functions, ranging from molecular and cellular processes to rhythms in physiology and behavior. At the cellular level, the circadian clockwork comprises interlocked transcriptional/translational feedback loops driven by a small set of clock genes and proteins. Circadian clock genes are present in all tissues and cell types, including neurons. Disruption of clock genes in the brain is associated with loss of circadian behavioral and physiological rhythms and other disturbances, including changes in motivation and cognition. In this presentation I will describe work from my laboratory on the regulation and function of circadian clock genes in the striatum, a critical region in the control of reward processing and appetitive and consummatory behaviors. In particular, I will first discuss the role of dopamine in the regulation of rhythmic clock gene expression in medium spiny neurons, the principal projection neurons of the striatum. I will then describe the impact of selective disruption of clock gene expression in these neurons on alcohol drinking, a behavior that depends on dopamine signaling in the striatum. Results will show that circadian clocks in the striatum exert a selective, sexually dimorphic influence on alcohol consumption in mice, conferring protection in males and risk in females without affecting reward sensitivity or global circadian rhythms.