Music and Emotion in Autism: a fMRI Study

Background: Autism Spectrum Disorders (ASD) dramatically impair interpersonal behaviours, sociality and communication.  A specific deficit in the ability to express and understand emotions has often been hypothesized to be an important correlate underlying such social impairments.  Studies have so far thoroughly explored the deficit of individuals with ASD in identifying emotions in visual stimuli (facial expressions) but little is known about their ability to perceive emotions conveyed by auditory stimuli such as music.  Music has been found to be capable to evoke and convey strong and consistent positive and negative emotions in healthy subjects (Koelsch et al 2005, 2006;  Mitterschiffthaler et al 2007).  Neuroimaging studies on healthy adults have brought to light the neural correlates of emotional processing of music.  In particular a network of limbic and paralimbic structures implicated in reward and emotion is observed in response to music (Zatorre 1994;  Blood  et al 1999;  Blood and Zatorre 2001). Research in autism has highlighted a relatively intact or superior musical pitch processing (Bonnel et al 2003;  Heaton 2003, 2005; Mottron et al 2000).  Yet, behavioural studies on ASD subjects have reported their ability to properly identify the positive or negative emotional valence of music stimuli (Heaton et al 1999, 2001).  

Objectives: This study uses functional magnetic resonance imaging (fMRI) to identify the neural correlates of emotion processing in subjects with Autism Spectrum Disorders (ASD) during music perception.  The aim is to provide a neurobiological support to the behavioural studies reporting a preserved ability to identify emotions conveyed by music in subjects with ASD.

Methods:  Five high-functioning ASD adults subjects (19 and 32 years) participated to the study. The ASD subjects underwent a single fMRI session in a 4T scanner using a passive music listening paradigm with preferred musical excerpts, classical musical excerpts and sequences of random tones.  All the stimuli were presented in a blocked design of 30s of musical pieces, 30 s random tones interspersed with a 15s rest period.  fMRI data analysis was performed  using the SPM5 software (Wellcome Department of Imaging Neuroscience, London). Results: A single subject analysis first contrasted both preferred musical excerpts and classical musical excerpts with a rest  period.  This analysis revealed activation in auditory temporal pole, with a bias towards the right hemisphere,  which is in line with the reported preserved ability of music processing.  A further analysis comparing the musical excerpts excerpts with the sequences of random tones showed a quite heterogeneous pattern of brain activity. In most of the cases preferred but not standard classical excerpts elicited increased activation of limbic and/or paralimbic structures usually involved in emotional processing.

Conclusions: These preliminary results indicate the altered and preserved cerebral brain circuitries involved in the emotional processing of music in ASD subjects . A larger group study may enhance our knowledge of emotional skills and deficit in ASD and may provide the neurobiological bases for the interventions based on music therapy which seem to facilitate communication in ASD subjects (Edgerton et al 1994;  Ma et al 2001;  Kern et al 2006, 2007;  de Falco et al 2006).