Interhemispheric connectivity of primary sensory cortex is associated with motor impairment after stroke

• Published in: Scientific reports Vol. 8; no. 1; pp. 12601 - 10
• Main Authors: Frías, Ilse, Starrs, Faryn, Gisiger, Thomas, Minuk, Jeffrey, Thiel, Alexander, Paquette, Caroline
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 22.08.2018; Nature Publishing Group
• Subjects: 59/36; 59/57; 692/53/2421; 692/53/2422; 692/53/2423; 692/617/375/1370/534; Brain research; Cerebral hemispheres; Cortex (motor); Functional magnetic resonance imaging; Hemispheric laterality; Humanities and Social Sciences; Lesions; Medical imaging; Motor skill learning; multidisciplinary; Neural networks; Neuroimaging; Neurological complications; Pyramidal tracts; Science; Science (multidisciplinary); Seeds; Somatosensory cortex; Stroke
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-29751-6

Neuroimaging-derived markers are used to model post-stroke impairment. Among these, lesion size, corticospinal-tract lesion-load (CST-LL) and resting-state functional-connectivity (rs-FC) have been correlated with impairment. It has been shown that the sensory cortex (S1) is associated with motor learning and is essential for post-stroke recovery; yet stroke-induced changes in S1 connectivity alone are yet to be investigated. We aim to determine whether interhemispheric rs-FC could be used to refine imaging models of stroke-related impairment. Subjects’ post-stroke and age-matched controls underwent rs-fMRI. Stroke-related disability was correlated with lesion size, CST-LL and interhemispheric S1 and M1 rs-FC as independent seeds. Regression analyses were performed to assess the contribution of these markers in stroke-related deficits. Post-stroke subjects showed an asymmetrical pattern of rs-FC in which affected hemisphere S1 and M1 were mostly connected with ipsi-lesional regions. Correlations between rs-FC and stroke-severity were found. Adding rs-FC of S1 to the regression model of impairment decreased the variance 31% compared to lesion size only. After a stroke, S1 interhemispheric connectivity is decreased, with S1 only connected with ipsi-lesional regions. This asymmetry correlates with neurological and motor impairment. Furthermore, when combined with lesion anatomical measures, S1 connectivity might be an important marker in explaining stroke outcome.