Autism Flashcards
What’s the heritability for Autism?
TWINS: 70% concordance rate in MZ Twins. 5% for DZ twin. 90% concordance for autism sprectrum disorder (ASD).
Sibs: 19% liklihood of having ASD if older sibling has it
32% if multiple older siblings have it.
*Also can happen due to a variety of genetic mutations.
What are some perinatal conditions of Autism?
Estimated 10% of cases are secondary to another medical disorder: rubella during pregnancy, excephalitis due to herpes, tuberous sclerosis.
Events that interfered with prenatal dvlpmt that may have caused autism?
Thalidomide: used for morning sickness during pregnancy in the 60’s and led to birth abnormalities including autism.
determined that critical per. for exposure to thalidomide was 20-36 days after conception.
this was during the per. of ORGANOGENESIS - begninning of formation of major organs.
What is the growth patten of an autistic brain?
by age 2-3 it’s 10% larger than normal, and after this growth spurt, growth slows down. By adolescence 1-2% larger than normal.
Which cortex is most involved in Autism?
Frontal and Temporal Cortex
What happens to the frontal & temporal cortex during brain growth in Autism?
Grows rapidly the first two years of life w/ little increase in the next 4 years.
Normal brain growth from age 2-6 has frontal lobe (20% growth) and temporal 17% growth.
What other areas are developed normally for autism during 2-6 yr?
Lower cortical areas - the primary and association visual cortex.
What happens to the amygdala in autistic individuals during this age?
Larger amygdalas by age 4 and it’s same size by adulthood but with less neurons.
What white-matter abnormalities happens in Autism?
increase volume of white matter w/ short range neurons.
No increase in white matter w/ long range neurons
What do the short & long range (white matter) neurons do?
Short, connects closely related brain structures together
Long, connects further away brain structures
What happens as a result of an over-production of neurons in early development?
A large number of short range neurons that develop may inhibit the production of long range neurons.
The exceptional isolated talents of some autistic patients may be a result of what?
Apparent hyperconnectivity of local regions of the brain (i.e., short range neurons)
In an animation with triangles looking at autism and brain functioning, what did they find?
Autistics had more difficulty identifying INTENTION in animations, but NOT goal-directed behs.
What did the PET scan show of autistic patients in the triangle animation task?
Showed autistic symptoms had Decreased activation of R extrastriate visual cortex and Decreased activation of R Superior Temporal Sulcus, and R Medial Prefrontal cortex.
In facial processing, what do autstic patients display?
Lower rate of eye contact
Poor at recognizing facial exp of emotion
Poor at recognizing direction of others’ gaze
