Abstract
Autism spectrum conditions (ASC) are characterised by deficits in understanding and expressing emotions and are frequently accompanied by alexithymia, a difficulty in understanding and expressing emotion words. Words are differentially represented in the brain according to their semantic category and these difficulties in ASC predict reduced activation to emotion-related words in limbic structures crucial for affective processing. Semantic theories view ‘emotion actions’ as critical for learning the semantic relationship between a word and the emotion it describes, such that emotion words typically activate the cortical motor systems involved in expressing emotion actions such as facial expressions. As ASC are also characterised by motor deficits and atypical brain structure and function in these regions, motor structures would also be expected to show reduced activation during emotion-semantic processing. Here we used event-related fMRI to compare passive processing of emotion words in comparison to abstract verbs and animal names in typically-developing controls and individuals with ASC. Relatively reduced brain activation in ASC for emotion words, but not matched control words, was found in motor areas and cingulate cortex specifically. The degree of activation evoked by emotion words in the motor system was also associated with the extent of autistic traits as revealed by the Autism Spectrum Quotient. We suggest that hypoactivation of motor and limbic regions for emotion word processing may underlie difficulties in processing emotional language in ASC. The role that sensorimotor systems and their connections might play in the affective and social-communication difficulties in ASC is discussed.
Highlights
Inherent in Kanner's first description of autism as a ‘disturbance of affective contact’ (Kanner, 1943), the domain of emotion has been cardinal throughout the history of autism research
Regions where emotion words evoked greater activity in TD than Autism spectrum conditions (ASC) participants are displayed in Table 1 and Fig. 1 (p b 0.05, Family-Wise Error (FWE) corr.)
Using event-related fMRI, we explored the representation of emotion words in comparison to abstract verbs and animal names in the typical population and people with ASC
Summary
Inherent in Kanner's first description of autism as a ‘disturbance of affective contact’ (Kanner, 1943), the domain of emotion has been cardinal throughout the history of autism research. R.L. Moseley et al / NeuroImage 104 (2015) 413–422 known as alexithymia, is much more prevalent in people with ASC (Lombardo et al, 2007; Hill et al, 2004) and their parents (Szatmari et al, 2008). Moseley et al / NeuroImage 104 (2015) 413–422 known as alexithymia, is much more prevalent in people with ASC (Lombardo et al, 2007; Hill et al, 2004) and their parents (Szatmari et al, 2008) It seems that individuals with ASC are atypical in how they express emotions in comparison to typically-developing peers and that, likewise, their perception and mirroring of emotions are reduced, if not impaired
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