Lecture 32: Autism

Question 1

What is the prevalence of autism spectrum disorders?

Answer 1

ASD = 1%

Autism proper = .25%

Question 2

How heritable is autism?

Answer 2

Highly heritable
Sibling recurrence risk = 20%
Heritability = 37 – 84% (75% if you go by the MZ and DZ concordance)

Question 3

How heterogeneous is autism?

Answer 3

Very heterogeneous
“If you have seen 1 child with autism, you have seen 1 child”
100s of separate disorders

Question 4

What is the triad of autism disorder?

Answer 4

1. Communication impairment
2. Restricted interest and compulsive behavior
3. Social impairment
   Onset by 3 y.o.
   Developmental disorder so NOT acquired

Question 5

What is aspergers?

Answer 5

1. Social impairment
2. Restricted interest & compulsive behavior
   Can communicate well

Question 6

What is the difference between autism and Asperger disorder?

Answer 6

Autism has 3 key traits

1. Social impairment
2. Restricted interests/compulsivity
   
   • Behavioral deficit!
3. Communication impairment

Asperger only has 2 out of 3 traits

- social impairment
- restricted interes & compulsive behavior

Question 7

What is wrong with DSM 4 subtypes?

Answer 7

Not predicted by biology and treatment responses
-lack external validity
-language delays NOT universal in ASD nor unique
Criteria not stable over time; not reliable between centers/clinicians
“cleaving meatloaf at the joints”
Social and communicative deficits predict one another
Asperger vs. Autism = are not completely distinct

Question 8

What is PPD-NOS?

Answer 8

Pervasive Developmental Disorder, Not Otherwise Specified
One of 5 autism spectrum disorders
-atypical autism

Question 9

Are there any drugs that treat the triad of autism?

Answer 9

No Cat

Question 10

What is the role of environmental factors?

Answer 10

There are 80,000 new synthetic chemicals in last 50 years
3% of neurobehavioral disorders by direct exposure
25% via epigenetic modification
Thought to play bigger role than genes?

Question 11

When does symptom expression occur?

Answer 11

Second year of life

Question 12

What is the biggest risk factor for autism?

Answer 12

If your sibling has autism

Question 13

What prenatal exposures are known to cause autism?

Answer 13

1. Thalidomide
2. Valproic acid
3. Maternal rubella infection

Question 14

What does thalidomide lead to?

Answer 14

Autism

Valproic acid and maternal rubella infection leads to autism too

Question 15

What is the one key genetic mutation that may cause autism?

Answer 15

Fragile X Syndrome

Question 16

Significance of Fragile X syndrome?

Answer 16

Symptoms look like autism

Has to do with mGluR mutations

Question 17

What is mGlur? Significance?

Answer 17

Metabotropic glutamate receptor
Important pathway in ASD symptomatology
-either too little or too much mGluR = ASD
Leads to Fragile X syndrome

Question 18

The brain size of autistic children is bigger or smaller?

Answer 18

Bigger

Question 19

What did Schultz find using diffuse tract imaging?

Answer 19

There was different axonal wiring in babies with autism

-led to blunted development

Question 20

What are the brain regions with LESS brain activity in ASD?

Answer 20

1. Fusiform gyrus
   
   • person perception
2. Superior Temporal Sulcus
   
   • facial expression perception
3. Amygdala
   
   • social arousal, attention/salience
4. Superior frontal gyrus
   
   • theory of mind
5. Ventral striatum
   
   • reward system/ADDICTION)
6. Lack of synchronicity among regions

Question 21

What is the fusiform gyrus? Significance?

Answer 21

Gyrus of temporal + occipital lobe
Is activated during person IDENTIFICATION
Decrease level of activity in autism

Question 22

What is one key characteristic of autism?

Answer 22

Kid focuses on objects a lot more than with kids

• there is no reward for looking at other people but for objects
  
  • not true for every autistic kid

Question 23

What does heuristic mean?

Answer 23

Enabling a person to discover or learn something for themselves

Question 24

What is the heuristic model for autism?

Answer 24

A model of treatment for autistic kids

Starts with SOCIAL MOTIVATION  increase social perception  increased social cognition

Question 25

How do we diagnose young kids with autism?

Answer 25

Track eyes to see what person is looking at
Looking at objects OVER looking at person is diagnostic
Less reward (less dopamine) for looking at people
More reward for looking at objects

Question 26

How do we treat kids with autism?

Answer 26

Intervene at social motivation

Example: give kids oxytocin for appropriate behavior and perception to reward interacting with other people, etc.