The Motivated Brain
When the brain is motivated following changes include, most prominently, the amygdala, which responds to, and directs learning about, emotionally salient stimuli ; the striatum, which plays a critical role in the acquisition, execution and invigoration of behavior that is instrumental for incentive attainment; and the orbitofrontal cortex (OFC), which evaluates the hedonic impact of the manifest reinforcers encountered by the individual. These three structures receive highly processed and integrated information through association cortices such as the insula, which represents a critical interface between autonomic bodily responses to incentives and core structures of the motivational brain and plays a role in memory for incentive value. Amygdala, striatum and OFC interact with each other and send their output to the motor cortex for the regulation of behavior and to the brain stem and hypothalamus for the regulation of autonomic responses, including hormone release. Amygdala, striatum and OFC as well as the insula are involved in identifying and responding to positive and negative incentives, and all of these structures are also involved in processing facial expressions of emotion.