Grant: Doctoral Award - Frederick Banting and Charles Best Canada Graduate Scholarships

We are constantly confronted with decisions involving both benefits and associated costs. One such type of decision involves whether we should exert effort in order to obtain a reward. We may choose to be lazy, expending minimal energy or resources for a minimal reward, or we may choose to work for a greater reward. Understanding the neural basis of mental effort may provide new therapeutic targets for illnesses such as depression and attention deficit hyperactivity disorder, where lack of motivation and poor effort strategies can hinder decision-making. A substantial body of research has revealed a circuit of brain structures involved in effort decision-making; when these structures are damaged, some patients have reported losing their sense of mental strain altogether. Rats with similar brain damage no longer exert a greater physical effort (such as climbing a barrier or pressing a lever multiple times) for a greater reward, though their ability to perform such effortful tasks is unaffected. To date, animal models of effort decision-making have only involved tasks that differed in the level of physical investment required, whereas most human studies utilize tasks where cognitive effort is varied. A novel animal model has been designed by Dr. Catharine Winstanley's laboratory to probe decision-making involving cognitive effort. Rats can choose either an easy task where the potential reward (sugar) is small or a hard task where the potential reward is large. Using this task, we will examine three aspects of decision-making: the brain structures and neurochemistry that underlie mental effort, the relationship between cognitive and physical effort (i.e. if are they the same, in terms of the brain), and finally some of the biological differences between hard-working and "lazy" animals. This research may provide insight into treating the compromised decision-making that a significant number of patients live with daily.