Structural and Functional Brain Imaging in Autism Spectrum Disorders

Abstract

Damasio and Maurer (1978) proposed that autism occurs due to structural and functional abnormalities at mesolimbic (dopaminergic) brain areas (ventromedial prefrontal cortex, medial temporal lobes, limbic striatum and thalamus), as damage to these brain regions can cause features of autism (impaired social and emotional functioning, stereotyped behaviours, mannerisms and obsessionality) [1]. This hypothesis is supported by studies in animals and human [2]. Areas outside the limbic system, such as the parietal lobes, are associated with autism. The lack of attention about understanding significant social cues in autism is similar to negligence and attention deficiency in the parietal lobe damage [3]. In addition to structural abnormalities in the cerebellum, another aetiological factor associated with autism is functional deterioration in cerebellar-cortical serotonergic pathways due to acquired cerebellar lesions, which can lead to impairment in social and emotional behaviour and impairment in executive functions and obsessions [4]. Brain imaging techniques are used in the investigation of these proposed structural and functional changes within autistic spectrum disorders.