Brain Mapping for Autism: A New Frontier in Neuroscience

Autism is a neuro -biological developmental condition that is associated with prevalence with various communication, learning and interactive traits. Many scientific brain imaging researches conducted on autism have reported that these traits originated because of

Alterations in how different parts of the brain form and connected to each other .
A few brain regions that are structurally distinct in people with autism.
Due to some irregularities in the grey and white matter

One of such studies by Horwitz et al. using Positron Emission Tomography (PET) has reported a connection between Autism Spectrum Disorder and abnormal brain activity, and study done by Lange et al. also noted it to be a dynamic disorder with complex changes in the brain over time from childhood into adulthood. However, there is no such standardised structuring of the brain or a single pattern of changes in any autistic child , but an understanding of brain mapping can help develop specific treatments and intervention for the various subtypes.

This are some of findings as reported by various studies done on Autism and associated brain structuring. New studies are continually adding to the existing knowledge on their brain structure and function.

The most common finding was the rapid growth in the total brain volume within 2-4 years of age which however shows a possible decline in after around 10-15 years of age .
An enlarged brain volume of the frontal and temporal lobes makes it difficult to manage emotions, storing and retrieving information .
Excess cerebrospinal fluid often resulting in an enlarged head. The excess fluid appears as early as 6 months of age and continues to accumulates slowly as the child grows, gradually starts exhibiting autistic traits.
Increased left parietal volumes is related to delayed speech in autism.
An oversize hippocampus, interrupts memory retention and hence in overall learning process.
A smaller amygdala affects the intensity of anxiety among the autistic kids^,
A smaller cerebellum, interferes in the coordination of movements and in other cognitive and social interactive process as well.
A thickened cortex may cause motor deficit and the orbitofrontal cortex and caudate nucleus are found to be associated with Repeated restricted behaviour among autistic kids.
The inferior frontal gyrus (IFG, Broca's area), superior temporal sulcus (STS), and Wernicke's area might be related to defects in social language processing and social attention.
Studies reported that bundles of long neuron fibres i.e the white matter is different in case of autistic children. They are responsible for connection of the various brain regions. Example abnormality of corpus callosum that connects the two hemispheres of the brain and other connections throughout the brain may have an increased chance of onset of autistic traits.

References

https://www.thetransmitter.org/spectrum/brain-structure-changes-in-autism-explained/?fspec=1

https://www.kenhub.com/en/library/anatomy/orbitofrontal-cortex

Szczupak D, Kossmann Ferraz M, Gemal L, Oliveira-Szejnfeld PS, Monteiro M, Bramati I, Vargas FR; IRC5 Consortium; Lent R, Silva AC, Tovar-Moll F. Corpus callosum dysgenesis causes novel patterns of structural and functional brain connectivity. Brain Commun. 2021 May 14;3(2):fcab057. doi: 10.1093/braincomms/fcab057. PMID: 34704021; PMCID: PMC8152904.

Redcay E. The superior temporal sulcus performs a common function for social and speech perception: implications for the emergence of autism. Neurosci Biobehav Rev. 2008;32(1):123-42. doi: 10.1016/j.neubiorev.2007.06.004. Epub 2007 Jul 6. PMID: 17706781.

Stoodley CJ. Distinct regions of the cerebellum show gray matter decreases in autism, ADHD, and developmental dyslexia. Front Syst Neurosci. 2014 May 20;8:92. doi: 10.3389/fnsys.2014.00092. PMID: 24904314; PMCID: PMC4033133.

Nordahl CW, Iosif AM, Young GS, Hechtman A, Heath B, Lee JK, Libero L, Reinhardt VP, Winder-Patel B, Amaral DG, Rogers S, Solomon M, Ozonoff S. High Psychopathology Subgroup in Young Children With Autism: Associations With Biological Sex and Amygdala Volume. J Am Acad Child Adolesc Psychiatry. 2020 Dec;59(12):1353-1363.e2. doi: 10.1016/j.jaac.2019.11.022. Epub 2020 Jan 20. PMID: 31972262; PMCID: PMC7369216.

Horwitz B, Rumsey JM, Grady CL, Rapoport SI. The cerebral metabolic landscape in autism. Intercorrelations of regional glucose utilization. Arch Neurol. 1988 Jul;45(7):749-55. doi: 10.1001/archneur.1988.00520310055018. PMID: 3260481.

Lange N, Travers BG, Bigler ED, Prigge MB, Froehlich AL, Nielsen JA, Cariello AN, Zielinski BA, Anderson JS, Fletcher PT, Alexander AA, Lainhart JE. Longitudinal volumetric brain changes in autism spectrum disorder ages 6-35 years. Autism Res. 2015 Feb;8(1):82-93. doi: 10.1002/aur.1427. Epub 2014 Nov 7. PMID: 25381736; PMCID: PMC4344386.

Ha S, Sohn IJ, Kim N, Sim HJ, Cheon KA. Characteristics of Brains in Autism Spectrum Disorder: Structure, Function and Connectivity across the Lifespan. Exp Neurobiol. 2015 Dec;24(4):273-84. doi: 10.5607/en.2015.24.4.273. Epub 2015 Dec 16. PMID: 26713076; PMCID: PMC4688328.

Courchesne E. Abnormal early brain development in autism. Mol Psychiatry. 2002;7 Suppl 2:S21-3. doi: 10.1038/sj.mp.4001169. PMID: 12142938.

Courchesne E, Campbell K, Solso S. Brain growth across the life span in autism: age-specific changes in anatomical pathology. Brain Res. 2011 Mar 22;1380:138-45. doi: 10.1016/j.brainres.2010.09.101. Epub 2010 Oct 1. PMID: 20920490; PMCID: PMC4500507.

Shen MD, Nordahl CW, Young GS, Wootton-Gorges SL, Lee A, Liston SE, Harrington KR, Ozonoff S, Amaral DG. Early brain enlargement and elevated extra-axial fluid in infants who develop autism spectrum disorder. Brain. 2013 Sep;136(Pt 9):2825-35. doi: 10.1093/brain/awt166. Epub 2013 Jul 9. PMID: 23838695; PMCID: PMC3754460.

Zoccante, Leonardo & Viviani, Anna & Ferro, Adele & Cerini, Roberto & Cerruti, Stefania & Rambaldelli, Gianluca & Bellani, Marcella & Dusi, Nicola & Perlini, Cinzia & Boscaini, Flavio & Pozzi Mucelli, Roberto & Tansella, Michele & Dalla Bernardina, Bernardo & Brambilla, Paolo. (2010). Increased left parietal volumes relate to delayed language development in autism: a structural mri study. Functional neurology. 25. 217-21.

Schumann CM, Hamstra J, Goodlin-Jones BL, Lotspeich LJ, Kwon H, Buonocore MH, Lammers CR, Reiss AL, Amaral DG. The amygdala is enlarged in children but not adolescents with autism; the hippocampus is enlarged at all ages. J Neurosci. 2004 Jul 14;24(28):6392-401. doi: 10.1523/JNEUROSCI.1297-04.2004. PMID: 15254095; PMCID: PMC6729537.