Neural systems for aversively motivated behavior

The neural basis of motivation is supported by brain systems that are integral in behaviors that maximize positively valued stimuli and minimize aversive stimuli. This article focuses on brain systems involved in minimization of aversive stimuli, which are extensively described by a substantial history of research on behaviors in nonhuman animals that are motivated by aversive stimuli. Such research strongly delineates a neural circuitry involving amygdala and striatum sub-nuclei that are modulated by regions of prefrontal cortex. Neuroimaging research on behaviors motivated by aversive stimuli in humans has confirmed the importance of homologous systems in humans, and allowed some understanding of the relation of these circuits to distinct behavioral responses and to clinical issues such as anxiety. We organize our review of this research around three important conceptual observations. First, active avoidance behaviors are distinguishable from passive avoidance behaviors in terms of both neural circuitry and motivational and affective consequences. Second, the perception of control over stimuli is critical for active avoidance behaviors, and influences brain systems for avoidance as well as subsequent behavior toward motivational stimuli. Third, avoidance behaviors may be adaptive in many situations but can become excessive or maladaptive in other situations. Knowledge about the neural circuitry underlying active avoidance provides an important path in understanding how avoidance behaviors are maintained and how they may change, and form a foundation for studying motivation and clinical issues such as anxiety.