Impaired Communication Between the Motor and Somatosensory Homunculus Is Associated With Poor Manual Dexterity in Autism Spectrum Disorder

Abigail Thompson*, Declan Murphy, Flavio Dell'Acqua, Christine Ecker, Grainne McAlonan, Henrietta Howells, Simon Baron-Cohen, Meng Chuan Lai, Michael V. Lombardo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

69 Citations (Scopus)
272 Downloads (Pure)


Background: Fine motor skill impairments are common in autism spectrum disorder (ASD), significantly affecting quality of life. Sensory inputs reaching the primary motor cortex (M1) from the somatosensory cortex (S1) are likely involved in fine motor skill and specifically motor learning. However, the role of these connections has not been directly investigated in humans. This study aimed to investigate, for the first time, the role of the S1-M1 connections in healthy subjects in vivo and whether microstructural alterations are associated with motor impairment in ASD. Methods: Sixty right-handed neurotypical adult men aged 18 to 45 years, and 60 right-handed age- and sex-matched subjects diagnosed with ASD underwent fine motor skill assessment and scanning with diffusion tensor imaging (DTI). The streamlines of the hand region connecting S1-M1 of the motor-sensory homunculus were virtually dissected using TrackVis, and diffusion properties were extracted. The face/tongue region connections were used as control tracts. Results: The ASD group displayed lower motor performances and altered DTI measurements of the hand-region connection. Behavioral performance correlated with hand-region DTI measures in both groups, but not with the face/tongue connections, indicating anatomical specificity. There was a left-hemisphere association of motor ability in the control group and an atypical rightward shift in the ASD group. Conclusions: These findings suggest that direct interaction between S1 and M1 may contribute to the human ability to precisely interact with and manipulate the environment. Because electrophysiological evidence indicates that these connections may underpin long-term potentiation in M1, our findings may lead to novel therapeutic treatments for motor skill disorders.

Original languageEnglish
JournalBiological psychiatry
Early online date1 Jul 2016
Publication statusE-pub ahead of print - 1 Jul 2016


  • Autism
  • Diffusion tensor imaging
  • Homunculus
  • Motor skill
  • Primary motor cortex
  • Somatosensory cortex
  • Tractography


Dive into the research topics of 'Impaired Communication Between the Motor and Somatosensory Homunculus Is Associated With Poor Manual Dexterity in Autism Spectrum Disorder'. Together they form a unique fingerprint.

Cite this