biological explanations of asd

genes, amygdala

amygdala function

• left: positive and negative emotions

• right: negative emotions

• processed emotions like fear and anxiety

• connected to the prefrontal cortex, hippocampus, hypothalamus and other areas

amygdala development

• nordahl

• found that from 2 years of age, there is a larger growth in amygdala volume in children with ASD (6-(%)

• the growth in volume occurs earlier in children with ASD and this may result in abnormalities in the neural organisation of the amygdala and damage its functioning

nordhal characteristics explanation

• difficulty maintaining friendship

• lack reciprocity

• not being able to identify social cues

amygdala dysfunction

• baron-cohen

• asd adults matched with control group with no asd. pictures with eyes and asked to identify the expression shown. brain activity recorded using fMRI scan

• asd group performed significantly worse than controls

• fMRI scans shows that the left amygdala was not activated in the ASD group but strongly in controls

baron cohen characteristics explanation

lack of social emotional reciprocity - meaning that amygdala function does not perform the same in someone with ASD, than a neurotypical person

amygdala dysfunction: supporting evidence

• baren-cohen studied ASD/ neurotypical completing emotions in the eyes task, whilst having an fMRI scan

• asd scored lower and showed no activation in left amygdala

• therefore, strength because supported by scientific evidence, increases credibility of explanation

amygdala dysfunction: deterministic

• asd is determined by biological factors e.g. left amygdala not activated in people with ASD

• left amygdala processes positive and negative emotions, explaining the lack of social-emotional reciporcity

• therefore, makes people with ASD feel powerless and a lack of control over their disorder

amygdala dysfunction: reductionist

• reduces complex behaviour of AD to dysfunction of a small brain area. beneficial as it allows the role of the amygdala to be studied in detail and scientifically

• however, oversimplifies our understanding of ASD. fails to consider genetic factors such as disorder being inherited

• therefore, even though can benefit from detailed understanding of amygdala, limited understanding as a whole disorder

szatmari

• 20x greater risk of developing ASD if you have a sibling with it

• proportion of siblings of people diagnosed with asd

• concordance rate 2.2%

• without siblings with asd 0.11%

• therefore, some genetic contribution to developing asd

genes: ignores nature

• only considers innate factors such as de novo mutation

• fails to consider influence of nurture (refrigerator mother)

• ignoring one side of nature/nurture debate, understanding of disorder incomplete

genes: potential for improved diagnosis and intervention

• genetic testing capabilities increase, could use to identify existence of de novo mutation in children

• be used to identify potential risk of developing asd

• inform early intervention + support

• therefore, makes theory more useful