Detection of Functional Homotopy in Traumatic Axonal Injury

This study aimed to explore the interhemispheric intrinsic connectivity in traumatic axonal injury (TAI) patients.

Twenty-one patients with TAI (14 males, seven females; mean age, 38.71 ± 15.25 years) and 22 well-matched healthy controls (16 males, six females; mean age, 38.50 ± 13.82 years) were recruited, and from them we obtained resting-state fMRI data. Interhemispheric coordination was examined using voxel-mirrored homotopic connectivity (VMHC) and seed-based functional connectivity analysis was performed.

We observed significantly decreased VMHC in a number of regions in TAI patients, including the prefrontal, temporal, occipital, parietal, and posterior cingulate cortices, thalami and cerebellar posterior lobes. Subsequent seed-based functional connectivity analysis revealed widely disrupted functional connectivity between the regions of local homotopic connectivity deficits and other areas of the brain, particularly the areas subserving the default, salience, integrative, and executive systems. The lower VMHC of the inferior frontal gyrus and basal ganglia, thalamus, and caudate were significant correlated with the Beck Depression Inventory score, Clinical Dementia Rating score, and Mini-Mental State Examination score, respectively.

TAI is associated with regionally decreased interhemispheric interactions and extensively disrupted seed-based functional connectivity, generating further evidence of diffuse disconnection being associated with clinical symptoms in TAI patients.

• Traumatic axonal injury is associated with decreased interhemispheric connectivity • Traumatic axonal injury couples with widely disrupted functional connectivity • These alterations support the default, salience, integrative, and executive functions.