Processing Speed Predicts Behavioral Treatment Outcomes in Children with Attention-Deficit/Hyperactivity Disorder Predominantly Inattentive Type.

Neuropsychological functioning underlies behavioral symptoms of attention-deficit/hyperactivity disorder (ADHD). Children with all forms of ADHD are vulnerable to working memory deficits and children presenting with the inattentive form of ADHD (ADHD-I) appear particularly vulnerable to processing speed deficits. As ADHD-I is the most common form of ADHD presented by children in community settings, it is important to consider how treatment interventions for children with ADHD-I may be affected by deficits in processing speed and working memory. We utilize data collected from 199 children with ADHD-I, aged 7 to 11 years, who participated in a randomized clinical trial of a psychosocial-behavioral intervention. Our aims are first to determine whether processing speed or working memory predict treatment outcomes in ADHD-I symptom severity, and second whether they moderate treatment effects on ADHD-I symptom severity. Results of linear regression analyses reveal that baseline processing speed significantly predicts posttreatment ADHD-I symptom severity when controlling for baseline ADHD-I symptom severity, such that better processing speed is associated with greater symptom improvement. However, predictive effects of working memory and moderation effects of both working memory and processing speed are not supported in the present study. We discuss study limitations and implications of the relation between processing speed and treatment benefits from psychosocial treatments for children with ADHD-I.

The processing of animacy information is disrupted as a function of callous-unemotional traits in youth with disruptive behavior disorders.

Atypical amygdala responses to emotional stimuli have been consistently reported in youth with Disruptive Behavior Disorders (DBDs; Conduct Disorder/Oppositional Defiant Disorder). However, responding to animacy stimuli has not been systematically investigated. Yet, the amygdala is known to be responsive to animacy stimuli and impairment in responsiveness to animacy information may have implications for social cognitive development. Twenty-nine youth with DBDs and 20 typically developing youth, matched for IQ, age (Mage  = 14.45, SD = 2.05) and gender, completed a dot probe task during fMRI. Stimuli consisted of negative/faces, negative/objects, neutral/faces and neutral/objects images. Youth with DBDs, relative to typically developing youth, showed: i) reduced amygdala and lateral temporal cortex responses to faces relative to objects. Moreover, within the group of youth with DBDs, increasing callous-unemotional traits were associated with lesser amygdala responses to faces relative to objects. These data suggest that youth with DBDs, particularly those with high levels of CU traits exhibit dysfunction in animacy processing in the amygdala. This dysfunction may underpin the asociality reported in these youth.

The amygdala's response to face and emotional information and potential category-specific modulation of temporal cortex as a function of emotion.

The amygdala has been implicated in the processing of emotion and animacy information and to be responsive to novelty. However, the way in which these functions interact is poorly understood. Subjects (N = 30) viewed threatening or neutral images that could be either animate (facial expressions) or inanimate (objects) in the context of a dot probe task. The amygdala showed responses to both emotional and animacy information, but no emotion by stimulus-type interaction; i.e., emotional face and object stimuli, when matched for arousal and valence, generate comparable amygdala activity relative to neutral face and object stimuli. Additionally, a habituation effect was not seen in amygdala; however, increased amygdala activity was observed for incongruent relative to congruent negative trials in second vs. first exposures. Furthermore, medial fusiform gyrus showed increased response to inanimate stimuli, while superior temporal sulcus showed increased response to animate stimuli. Greater functional connectivity between bilateral amygdala and medial fusiform gyrus was observed to negative vs. neutral objects, but not to fearful vs. neutral faces. The current data suggest that the amygdala is responsive to animate and emotional stimuli. Additionally, these data suggest that the interaction between the various functions of the amygdala may need to be considered simultaneously to fully understand how they interact. Moreover, they suggest category-specific modulation of medial fusiform cortex as a function of emotion.

Empathic responsiveness in amygdala and anterior cingulate cortex in youths with psychopathic traits.

BACKGROUND: Psychopathic traits are associated with increases in antisocial behaviors such as aggression and are characterized by reduced empathy for others' distress. This suggests that psychopathic traits may also impair empathic pain sensitivity. However, whether psychopathic traits affect responses to the pain of others versus the self has not been previously assessed. METHOD: We used whole-brain functional magnetic resonance imaging to measure neural activation in 14 adolescents with oppositional defiant disorder or conduct disorder and psychopathic traits, as well as 21 healthy controls matched on age, gender, and intelligence. Activation in structures associated with empathic pain perception was assessed as adolescents viewed photographs of pain-inducing injuries. Adolescents imagined either that the body in each photograph was their own or that it belonged to another person. Behavioral and neuroimaging data were analyzed using random-effects analysis of variance. RESULTS: Youths with psychopathic traits showed reduced activity within regions associated with empathic pain as the depicted pain increased. These regions included rostral anterior cingulate cortex, ventral striatum (putamen), and amygdala. Reductions in amygdala activity particularly occurred when the injury was perceived as occurring to another. Empathic pain responses within both amygdala and rostral anterior cingulate cortex were negatively correlated with the severity of psychopathic traits as indexed by PCL:YV scores. CONCLUSIONS: Youths with psychopathic traits show less responsiveness in regions implicated in the affective response to another's pain as the perceived intensity of this pain increases. Moreover, this reduced responsiveness appears to predict symptom severity.

Reduced amygdala response in youths with disruptive behavior disorders and psychopathic traits: decreased emotional response versus increased top-down attention to nonemotional features.

OBJECTIVE: Amygdala dysfunction has been reported to exist in youths and adults with psychopathic traits. However, there has been disagreement as to whether this dysfunction reflects a primary emotional deficit or is secondary to atypical attentional control. The authors examined the validity of the contrasting predictions. METHOD: Participants were 15 children and adolescents (ages 10­17 years) with both disruptive behavior disorders and psychopathic traits and 17 healthy comparison youths. Functional MRI was used to assess the response of the amygdala and regions implicated in top-down attentional control (the dorsomedial and lateral frontal cortices) to emotional expression under conditions of high and low attentional load. RESULTS: Relative to youths with disruptive behavior disorders and psychopathic traits, healthy comparison subjects showed a significantly greater increase in the typical amygdala response to fearful expressions under low relative to high attentional load conditions. There was also a selective inverse relationship between the response to fearful expressions under low attentional load and the callous-unemotional component (but not the narcissism or impulsivity component) of psychopathic traits. In contrast, the two groups did not differ in the significant recruitment of the dorsomedial and lateral frontal cortices as a function of attentional load. CONCLUSIONS: Youths with disruptive behavior disorders and psychopathic traits showed reduced amygdala responses to fearful expressions under low attentional load but no indications of increased recruitment of regions implicated in top-down attentional control. These findings suggest that the emotional deficit observed in youths with disruptive behavior disorders and psychopathic traits is primary and not secondary to increased top-down attention to nonemotional stimulus features.