Electronic Thesis and Dissertation Repository


Master of Science




Dr. J. Bruce Morton


Stress can drastically alter the behavioural and functional correlates of feedback learning; however, the functional correlates of these effects are poorly understood, particularly in children. In the present study, typically developing children between the ages of 9- and 11-years-old completed a probabilistic learning task with both appetitive and aversive outcomes in a magnetic resonance imaging scanner. Anticipatory stress to the experimental environment was measured via salivary cortisol at baseline and prior to completion of the task. Although baseline and pre-MRI cortisol values were not reliably different at the group level, subsequent analyses revealed that the basolateral amygdala was less responsive to positive feedback in children with higher pre-MRI cortisol levels. Furthermore, individual differences in feedback-related basolateral amygdala activity were positively associated with differences in striatal activity. Thus, the basolateral amygdala may be particularly sensitive to individual differences in active cortisol levels, and may also modulate striatal feedback sensitivity.