Left-lateralization of resting state functional connectivity between the presupplementary motor area and primary language areas

Neuroreport. 2017 Jul 5;28(10):545-550. doi: 10.1097/WNR.0000000000000783.

Abstract

An abundance of evidence points to the role of a presupplementary motor area (pre-SMA) in human language. This study explores the pre-SMA resting state connectivity network and the nature of its connections to known language areas. We tested the hypothesis that by seeding the pre-SMA, one would be able to establish language laterality to known cortical and subcortical language areas. We analyzed data from 30 right-handed healthy controls and performed the resting state functional MRI. A seed-based analysis using a manually drawn pre-SMA region of interest template was applied. Time-course signals in the pre-SMA region of interest were averaged and cross-correlated to every voxel in the brain. Results show that the pre-SMA has significant left-lateralized functional connectivity to the pars opercularis within Broca's area. Among cortical regions, pre-SMA functional connectivity is strongest to the pars opercularis In addition, pre-SMA connectivity was shown to exist to other cortical language-association regions, including Wernicke's Area, supramarginal gyri, angular gyri, and middle frontal gyri. Among subcortical areas, considerable left-lateralized functional connectivity occurs to the caudate and thalamus, whereas cerebellar subregions show right lateralization. The current study shows that the pre-SMA most strongly connects to the pars opercularis within Broca's area and that cortical connections to language areas are left lateralized among a sample of right-handed patients. We provide resting state functional MRI evidence that the functional connectivity of the pre-SMA is involved in semantic language processing and that this identification may be useful for establishing language laterality in preoperative neurosurgical planning.

MeSH terms

  • Basal Ganglia / diagnostic imaging
  • Basal Ganglia / physiology
  • Brain Mapping
  • Cerebellum / diagnostic imaging
  • Cerebellum / physiology
  • Female
  • Functional Laterality*
  • Humans
  • Language*
  • Magnetic Resonance Imaging
  • Male
  • Motor Cortex / diagnostic imaging
  • Motor Cortex / physiology*
  • Neural Pathways / diagnostic imaging
  • Neural Pathways / physiology
  • Thalamus / diagnostic imaging
  • Thalamus / physiology
  • Young Adult