Conduct disorder and callous-unemotional traits in youth.

Overlap among Six Clinical Entities.The size of each circle represents the relative prevalence of the clinical entity in the community. ADHD denotes attention deficit–hyperactivity disorder, ASPD antisocial personality disorder, and ODD oppositional–defiant disorder.

Functional MRI Study of Face Processing.In the study, a child views a series of faces expressing various emotions. To ensure attention to each face, the child is asked to identify the sex of the person. In healthy children, faces with fearful expressions elicit greater amygdala activation than faces with neutral expressions. Faces with emotional expressions other than fear elicit activation in other structures, including the insula and prefrontal cortex. Amygdala activation in response to fearful faces is reduced in youth with conduct disorder and callous–unemotional traits, as compared with either healthy youth or those who have conduct disorder without callous–unemotional traits.

Relationships among the Proximity of a Threat, the Activity in a Particular Neural Circuit, and the Behavioral Response to the Threat.The neural circuit that is activated in response to a threat connects the amygdala, hypothalamus, and periaqueductal gray matter. The figure depicts a threat of increasing proximity, in the form of a bear that appears in the distance, somewhat closer, or very close and about to attack. The brain circuitry activity increases as the threat draws closer. Also shown are the different behaviors that are elicited as the proximity of the threat increases: from freezing to flight to fight.

Format of a Functional MRI Study of Decision Making and Brain-Activation Data as They Relate to Prediction-Error Signals in the Basal Ganglia.In this type of study, a research participant must learn to select one set of stimuli (e.g., the elephant) by pressing a button and to avoid another set of stimuli (e.g., the giraffe) by not pressing the button. Receipt of an unexpected reward elicits a positive prediction error (PE+), whereas failure to receive an expected reward, or a loss that is greater than expected, elicits a negative prediction error (PE−). The plots show responses to feedback in the basal ganglia during blood oxygen level–dependent functional MRI; the ventromedial prefrontal cortex is also shown. The timing of feedback is represented by the shaded column beginning at time zero. A PE+ occurs when the participant wins more than expected after pushing a button at the sight of the elephant. A PE− occurs when the participant loses more than expected after pushing a button at the sight of the giraffe. These positive and negative prediction errors generate the depicted reaction in the basal ganglia.