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Autism spectrum disorders or pervasive developmental disorders involve impairments in reciprocal social interactions as well as restricted repetitive patterns of behavior in the absence of obvious intellectual dysfunction. Even though the exact pathophysiology of autism remains to be established, it has been widely accepted that this condition strongly impact central nervous system function. Of the brain structures that have been proposed to play a crucial role in the neurobiology of the clinical features of autism, the contribution of the amygdala is particularly convincing. It is the impairments of autistic individuals to process emotional and social information that has left many health care professionals to hypothesize an association of the amygdala and autism.

Brain imaging studies show abnormalities in the amygdala in affected individuals. Conversely, most neuropathological results were non-specific and brain volumetric studies have been, for the most part, inconsistent. More significantly, researches assessing the participation of the amygdala failed to report associations with autism related behavioral and emotional impairments. Information on such correlations would be specifically supportive in providing information on whether the amygdala dysfunction is relevant to the etiology of autism; that is if they are indeed accurate pathophysiological mediator of autism.

Functional neuroimaging involving autistic individuals show less amydgala activation when inferring mental states, interpreting facial emotional expressions or in response to changing task demands in a mental task (Wang et al., 2004), as compared to normal persons.

Presently, no efforts have been made to determine the relationship between the amygdala to the diagnostic features of autism spectrum disorders according to the criteria in the Diagnostic and Statistical Manual of Mental Disorders version IV (DSM-IV) and the International Classification of Diseases version 10 (ICD-10). Although autistic symptomatologies include impairments social cognition and emotion recognition, which are representative of a diagnostic cluster in DSV-IV and ICD-10, they are not fundamental parts of the psychiatric diagnosis of autism.

A study investigated the direct relationship between amygdala function and autism in affected individuals (Dziobek et al., 2005). Patients with autism and normal controls were examined using brain imaging techniques derived amygdala volume and behavioral factors of emotion and social functioning and results of both groups were then compared to gain insight on the association between these to variables. Results show that patients with autism manifested dysfunction in emotional and social functioning as compared to normal individuals. They also showed an uncharacteristic association between amygdala volumes and overall head dimension. Positive associations were found between social and emotional understanding and amygdala volume in unaffected individuals, but this was not the case in patients with autism. Interestingly, when correlating amygdala volume with general brain size for the groups separately, there was a significant positive trend for normal individuals, while there was only a weak negative association in autistic patients. Volumetric analyses did not yield significant differences between the groups. Results indicated that in autism, the amygdala is not a key mediator for social and emotional functioning.

In general, clinical and experimental studies fail to provide clear-cut evidence to conclude that the amydala is indeed a major pathology in autism. Further research is deemed necessary to support significance of amydala dysfunction in pervasive developmental disorders.

Article Keywords: Autism

A Quick Note From The Publisher... If you like the article above, you may be interested in the following article which is also related to Autism... Help, my child has autism Autism is a spectrum disorder that affects an individual’s ability to communicate and relate to others. It is a type of pervasive developmental disorder (PDD) that is lifelong and can result in some social isolation. The cause of Autism is not known, although research has shown differences in brain structure between children with autism and non-autistic children. Some early research has also indicated that Autism could be genetic, with parents who have an autistic child more likely to have another child with autism. It has also being shown that autism is more prevalent in those who have certain conditions including untreated Phenylketonuria (PKU), Fragile X Syndrome, Tuberous Sclerosis and Congenital Rubella Syndrome. The symptoms of autism typically develop within the first three years of life. All people with Autism experience difficulty with social interaction, and children might prefer to play alone and make little eye contact with other people. Babies with autism may not babble talk and may also seem to have hearing difficulties. Language development is almost always delayed in children with autism. Sufferers may have difficulties in both verbal and non-verbal communication, have limited, patterned or over-used behaviour patterns, play and interests. These include repetitive body rocking, forming unusual attachments to objects and resisting change (holding to routines and rituals, for example). The world-wide incidence of autism is consistent around the globe, but it has been shown that it is four times more prevalent in boys than girls. The development of autism is not affected in any way by race, ethnicity, social boundaries, family income, lifestyle or educational levels. Article by health writer Kate Wiley of ...