title: Amygdala response to preattentive masked fear in children with conduct problems: the role of callous-unemotional traits.
abstract: OBJECTIVE
  In children with conduct problems, high levels of callous-unemotional traits are associated with amygdala hypoactivity to consciously perceived fear, while low levels of callous-unemotional traits may be associated with amygdala hyperactivity. Behavioral data suggest that fear processing deficits in children with high callous-unemotional traits may extend to stimuli presented below conscious awareness (preattentively). The authors investigated the neural basis of this effect. Amygdala involvement was predicted on the basis of its role in preattentive affective processing in healthy adults and its dysfunction in previous studies of conduct problems.
  
  
  METHODS
  Functional MRI was used to measure neural responses to fearful and calm faces presented preattentively (for 17 ms followed by backward masking) in boys with conduct problems and high callous-unemotional traits (N=15), conduct problems and low callous-unemotional traits (N=15), and typically developing comparison boys (N=16). Amygdala response to fearful and calm faces was predicted to differentiate groups, with the greatest response in boys with conduct problems and low callous-unemotional traits and the lowest in boys with conduct problems and high callous-unemotional traits.
  
  
  RESULTS
  In the right amygdala, a greater amygdala response was seen in boys with conduct problems and low callous-unemotional traits than in those with high callous-unemotional traits. The findings were not explained by symptom levels of conduct disorder, attention-deficit hyperactivity disorder, anxiety, or depression.
  
  
  CONCLUSIONS
  These data demonstrate differential amygdala activity to preattentively presented fear in children with conduct problems grouped by callous-unemotional traits, with high levels associated with lower amygdala reactivity. The study's findings complement increasing evidence suggesting that callous-unemotional traits are an important specifier in the classification of children with conduct problems.
authors.affiliation: Division of Psychology and Language Sciences, University College, London. e.viding@ucl.ac.uk
authors.forename: Essi
authors.initials: E
authors.lastname: Viding
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Sebastian
authors.forename: Mark R
authors.initials: MR
authors.lastname: Dadds
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Lockwood
authors.forename: Charlotte A M
authors.initials: CA
authors.lastname: Cecil
authors.forename: Stephane A
authors.initials: SA
authors.lastname: De Brito
authors.forename: Eamon J
authors.initials: EJ
authors.lastname: McCrory
mesh_terms: D000293:Adolescent; D000679:Amygdala / Q000503:physiopathology*; D001288:Attention / Q000502:physiology; D002648:Child; D019955:Conduct Disorder / Q000503:physiopathology* / Q000523:psychology; D004644:Emotions / Q000502:physiology*; D004645:Empathy; D005149:Facial Expression; D005239:Fear / Q000502:physiology*; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male