Lecture 12 - Autism

The Social Brain: Critical Perspectives on Science, Society and Neurodiversity

Richard Ramsey

Today


Part 1

  • Autism


Part 2

  • Read articles and discuss



Overview

  • Background
  • What factors cause autism?
    • Environmental
    • Genetic
    • Cognitive
    • Neurobiological
  • Many autisms?

Background

What is autism?

  • Lorna Wing’s triad of impairments:

    • difficulties in social interaction
    • difficulties in communication
    • lack of imagination / repetitive interests

  • Heterogeneous – no two people are the same.

  • There is a spectrum of different diagnoses.

Diagnosis


  • DSM criteria (Diagnostic and Statistical Manual of Mental Disorders, APA)
  • Clinical observation
  • Checklists
    • CHAT (checklist for autism in toddlers)
    • CARS (childhood autism rating scale)
    • DISCO (Diagnostic Interview for Social and Communication Disorders)
  • ADOS (Autism Diagnostic Observation Schedule)
  • ADI (Autism Diagnostic Interview)

(Hirota & King, 2023)

How many children have autism?


  • 3–4% of children and adolescents in the US
  • 1% of the global population
  • 0.7–1.5% in Switzerland
  • Male-to-female ratio of approximately 3–4:1.

(Grosvenor et al., 2024)

What factors cause autism?

Possible factors


  • environmental
    • vaccines
    • other environment?
  • genetic
  • cognitive
  • neurobiological

Vaccines


  • HELL NO!

  • There is a vast amount of high quality evidence that shows NO LINK between vaccines and autism.

  • For those who want to read more see here.

(DeStefano & Shimabukuro, 2019; Gabis et al., 2022)

Other environmental factors

  • Can a lack of a normal social environment cause autism?

    • “Refrigerator mother” - Bruno Bettelheim (1950’s) blamed “lack of maternal warmth” for autism in a child.
    • Theory is now totally discredited.

  • What about sensory deprivation?

    • Blind and deaf children show autistic-like symptoms (Brown et al., 1997; Wolfe et al., 2002).
    • Neither blind nor deaf show all the symptoms of autism.

  • Or extreme social deprivation?

    • Romanian orphanage studies (Rutter et al., 2007).
    • 10% had some autism symptoms at age 6, none had full symptoms, and many improved by age 12

Genetic

  • Bailey et al, 1995
    • 60% of MZ twin pairs were concordant for autism
    • no DZ twin pairs were concordant
    • shows high heritability (but not 100%)
  • Ronald et al, 2005
    • studied over 3000 twin pairs in TEDS
    • find social behaviour is 62-76% heritable

Many genes have been implicated, none conclusively.

(Bailey et al., 1995; Ronald et al., 2005)

Cognitive



Two different cognitive accounts:

  • Theory of mind

  • Weak central coherence

Theory of mind


  • The idea that people with autism have difficulty understanding other people’s mental states (beliefs, desires etc.).

  • Proponents include Frith, Leslie, Happe, Baron-Cohen

False beliefs


(Baron-Cohen et al., 1985; Happe, 1995)

Animated shapes

(Heider & Simmel, 1944)

Animated shapes, autism and fMRI

(Castelli et al., 2002)

Weak central coherence


  • The idea that people with autism have superior processing of detail and less superior processing of whole contexts.

  • It can account for many non-social features and strengths.

  • Do social tasks require more ‘central coherence’ than non-social tasks?

The emebedded figures task

(Shah & Frith, 1983)

The block design task


  • Part of WISC IQ test

  • Children with autism often perform very well on this task

(Shah & Frith, 1993)

Cognitive summary

  • ToM
    • Lack of ToM in autism could cause breakdown in social interaction and communication
    • But it can’t explain savant skills or repetitive behaviours
  • Weak central coherence
    • Weak central coherence could maybe account for many non-social features and strengths.
    • But do social tasks require more ‘central coherence’ than non-social tasks?

Neurobiological



Two different neurobiological accounts:

  • Broken mirror theory

  • Underconnectivity

Broken mirrors


  • The idea that the ‘mirror neuron system’ is dysfunctional in autism

  • Proponents include: Dapretto & Iacoboni, Oberman & Ramachandran, Justin Williams

  • Evidence from: imitation behaviour, fMRI, EEG

fMRI evidence

(Dapretto et al., 2006)

Broken mirror criticisms

  • Evidence for the theory is weak (Southgate & Hamilton A. F., 2008).
    • emotion and language tasks used, which are not the like the tasks that activate the mirror neurons in monkeys
    • types of imitation remain intact
  • Empirical evidence that EEG and mu rhythmns can serve as an index of mirror neuron system has been heavily questioned (Hobson & Bishop, 2016, 2017).

Underconnectivity


  • The idea that the cortex is not connected together correctly in autism

    • Underconnectivity could cause lots of information processing problems

  • Proponents include Minshew, Just, Courschesne

  • Evidence comes from fMRI studies

fMRI evidence

(Just et al., 2004, 2013)

Neurobiological summary

  • Broken mirror theory claims to explain many social features of autism, but it does not explain non-social features.

  • And …

    • We still don’t know if the MNS contributes to Theory of Mind or language.
    • Mostly indirect measures of MNS function.
    • Tasks are emotional or meaningless actions – not like the tasks that activate the monkey MNS.
  • Underconnectivity may explain weak central coherence
  • But …
    • it may not explain social / communication problems (unless social information processing requires more ‘connections’)

Many autisms?

  • No single factor gives a complete explanation
  • It is hard to explain both social and non-social symptoms

Time to give up on a single explanation for autism (Happé et al., 2006)

  • Should study each part of the triad separately
  • No model can yet account for all symptoms
  • Different genetic and cognitive causes for each

Take a break

Part 2 - Read and discuss

Discussion material

And some articles in the popular press:

Vaccines do not cause autism

So, what is going on in the United States?

References

Bailey, A., Couteur, A. L., Gottesman, I., Bolton, P., Simonoff, E., Yuzda, E., & Rutter, M. (1995). Autism as a strongly genetic disorder: Evidence from a British twin study. Psychological Medicine, 25(1), 63–77. https://doi.org/10.1017/S0033291700028099
Baron-Cohen, S., Leslie, A. M., & Frith, U. (1985). Does the autistic child have a "theory of mind"? Cognition, 21(1), 37–46. http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=2934210
Castelli, F., Frith, C., Happe, F., & Frith, U. (2002). Autism, Asperger syndrome and brain mechanisms for the attribution of mental states to animated shapes. Brain, 125, 1839–49. http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=12135974 http://brain.oupjournals.org/cgi/content/full/125/8/1839 http://brain.oupjournals.org/cgi/content/abstract/125/8/1839
Dapretto, M., Davies, M. S., Pfeifer, J. H., Scott, A. A., Sigman, M., Bookheimer, S. Y., & Iacoboni, M. (2006). Understanding emotions in others: Mirror neuron dysfunction in children with autism spectrum disorders. Nat Neurosci, 9(1), 28–30. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16327784
DeStefano, F., & Shimabukuro, T. T. (2019). The MMR Vaccine and Autism. Annual Review of Virology, 6, 585–600. https://doi.org/10.1146/annurev-virology-092818-015515
Gabis, L. V., Attia, O. L., Goldman, M., Barak, N., Tefera, P., Shefer, S., Shaham, M., & Lerman-Sagie, T. (2022). The myth of vaccination and autism spectrum. European Journal of Paediatric Neurology, 36, 151–158. https://doi.org/10.1016/j.ejpn.2021.12.011
Grosvenor, L. P., Croen, L. A., Lynch, F. L., Marafino, B. J., Maye, M., Penfold, R. B., Simon, G. E., & Ames, J. L. (2024). Autism Diagnosis Among US Children and Adults, 2011-2022. JAMA Network Open, 7(10), e2442218. https://doi.org/10.1001/jamanetworkopen.2024.42218
Happe, F. G. (1995). The role of age and verbal ability in the theory of mind task performance of subjects with autism. Child Dev, 66(3), 843–855. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7789204
Happé, F., Ronald, A., & Plomin, R. (2006). Time to give up on a single explanation for autism. Nat Neurosci, 9(10), 1218–1220. https://doi.org/10.1038/nn1770
Heider, F., & Simmel, M. (1944). An Experimental Study of Apparent Behavior. The American Journal of Psychology.
Hirota, T., & King, B. H. (2023). Autism Spectrum Disorder: A Review. JAMA, 329(2), 157–168. https://doi.org/10.1001/jama.2022.23661
Hobson, H. M., & Bishop, D. V. M. (2016). Mu suppression – A good measure of the human mirror neuron system? Cortex, 82, 290–310. https://doi.org/10.1016/j.cortex.2016.03.019
Hobson, H. M., & Bishop, D. V. M. (2017). The interpretation of mu suppression as an index of mirror neuron activity: Past, present and future. Royal Society Open Science, 4(3), 160662. https://doi.org/10.1098/rsos.160662
Just, M. A., Cherkassky, V. L., Keller, T. A., & Minshew, N. J. (2004). Cortical activation and synchronization during sentence comprehension in high-functioning autism: Evidence of underconnectivity. Brain, 127(8), 1811–1821. https://doi.org/10.1093/brain/awh199
Just, M. A., Keller, T. A., & Kana, R. K. (2013). A Theory of Autism Based on Frontal-Posterior Underconnectivity. In Development and Brain Systems in Autism. Psychology Press.
Ronald, A., Happé, F., & Plomin, R. (2005). The genetic relationship between individual differences in social and nonsocial behaviours characteristic of autism. Developmental Science, 8(5), 444–458. https://doi.org/10.1111/j.1467-7687.2005.00433.x
Shah, A., & Frith, U. (1983). An Islet of Ability in Autistic Children: A Research Note. Journal of Child Psychology and Psychiatry, 24(4), 613–620. https://doi.org/10.1111/j.1469-7610.1983.tb00137.x
Shah, A., & Frith, U. (1993). Why do autistic individuals show superior performance on the block design task? J Child Psychol Psychiatry, 34(8), 1351–64. http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=8294523
Southgate, V., & Hamilton A. F. (2008). Unbroken mirrors: Challenging a theory of Autism. Trends Cogn Sci, 12(6), 225–229. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18479959

Acknowledgements