The functional neuroanatomy of social behaviour

Abstract

Although high-functioning individuals with autistic disorder (i.e. autism and Asperger syndrome) are of normal intelligence, they have life-long abnormalities in social communication and emotional behaviour. However, the biological basis of social difficulties in autism is poorly understood. Facial expressions help shape behaviour, and we investigated if high-functioning people with autistic disorder show neurobiological differences from controls when processing emotional facial expressions. We used functional MRI to investigate brain activity in nine adults with autistic disorder (mean age +/- standard deviation 37 +/- 7 years; IQ 102 +/- 15) and nine controls (27 +/- 7 years; IQ 116 +/- 10) when explicitly (consciously) and implicitly (unconsciously) processing emotional facial expressions. Subjects with autistic disorder differed significantly from controls in the activity of cerebellar, mesolimbic and temporal lobe cortical regions of the brain when processing facial expressions. Notably, they did not activate a cortical 'face area' when explicitly appraising expressions, or the left amygdala region and left cerebellum when implicitly processing emotional facial expressions. High-functioning people with autistic disorder have biological differences from controls when consciously and unconsciously processing facial emotions, and these differences are most likely to be neurodevelopmental in origin. This may account for some of the abnormalities in social behaviour associated with autism.

Abnormal early brain development in autism

“…Lastly, it is a reasonable assumption that pathological growth regulation during this critical period of early life could lead to widespread and pervasive consequences for the functional differentiation of systems mediating many neuro- behavioral domains. Evidence consistent with this prediction of aberrant functional organization in autism comes from recent fMRI studies of mature patients performing tasks involving movement, 11,12 face perception, 13,14 processing emotions, 15 and visual attention. 11 Interestingly, abnormally elevated brain neurotro-…”

Autism, social cognition and superior temporal sulcus

“…They found significantly less activation of the middle aspect of the right FFA in 14 high functioning individuals with ASD compared to controls [76]. Hypoactivation of the FFA was replicated in a series of functional studies [77][78][79]. In the same path, Critchley and colleagues investigated whether high functioning people with ASD showed a different pattern of cortical activation when processing facial expressions.…”

A psicologia como neurociência cognitiva: Implicações para a compreensão dos processos básicos e suas aplicações

“…Os poucos estudos de neuroimagem funcional existentes mostram igualmente alterações no padrão de activação amigdalar em resposta a estímulos ameaçadores e no processamento de faces (Haas et al, 2009;Meyer-Lindenberg et al, 2005), bem como alterações ao nível do córtex pré-frontal dorso-lateral em tarefas de inibição comportamental (Mobbs et al, 2007). Relativamente ao autismo, estudos estruturais apontam para a presença de reduzido volume amigdalar (Abell et al, 1999;Critchley et al, 2000) e de redução cortical da circunvolução temporal superior (Hadjikhani et al, 2006). Ao nível funcional, foi observada uma reduzida activação da amígdala em tarefas que implicam cognição social, como a inferência de estados mentais e o processamento de expressões emocionais faciais (Baron- Cohen et al, 1999;Critchley et al, 2000), bem como uma reduzida activação na circunvolução temporal superior em tarefas de processamento da informação social (Castelli, Frith, Happé, & Frith, 2002;Gervais et al, 2004).…”

“…Relativamente ao autismo, estudos estruturais apontam para a presença de reduzido volume amigdalar (Abell et al, 1999;Critchley et al, 2000) e de redução cortical da circunvolução temporal superior (Hadjikhani et al, 2006). Ao nível funcional, foi observada uma reduzida activação da amígdala em tarefas que implicam cognição social, como a inferência de estados mentais e o processamento de expressões emocionais faciais (Baron- Cohen et al, 1999;Critchley et al, 2000), bem como uma reduzida activação na circunvolução temporal superior em tarefas de processamento da informação social (Castelli, Frith, Happé, & Frith, 2002;Gervais et al, 2004).…”