Effects of thalamic infarction on the structural and functional connectivity of the ipsilesional primary somatosensory cortex
To identify regions causally influenced by thalamic stroke by measuring white matter integrity, cortical volume, and functional connectivity (FC) among patients with thalamic infarction (TI) and to determine the association between structural/functional alteration and somatosensory dysfunction.
Thirty-one cases with TI-induced somatosensory dysfunction and 32 healthy controls underwent magnetic resonance imaging scanning. We reconstructed the ipsilesional central thalamic radiation (CTR) and assessed its integrity using fractional anisotropy (FA), assessed S1 ipsilesional changes with cortical volume, and identified brain regions functionally connected to TI locations and regions without TI to examine the potential effects on somatosensory symptoms.
Compared with controls, TI patients showed decreased FA (F = 17.626, p < 0.001) in the ipsilesional CTR. TI patients exhibited significantly decreased cortical volume in the ipsilesional top S1. Both affected CTR (r = 0.460, p = 0.012) and S1 volume (r = 0.375, p = 0.049) were positively correlated with somatosensory impairment in TI patients. In controls, the TI region was highly functionally connected to atrophic top S1 and less connected to the adjacent middle S1 region in FC mapping. However, T1 patients demonstrated significantly increased FC between the ipsilesional thalamus and middle S1 area, which was adjacent to the atrophic S1 region.
TI induces remote changes in the S1, and this network of abnormality underlies the cause of the sensory deficits. However, our other finding that there is stronger connectivity in pathways adjacent to the damaged ones is likely responsible for at least some of the recovery of function.
• TI led to secondary impairment in the CTR and cortical atrophy in the ipsilesional top of S1.
• TI patients exhibited significantly higher functional connectivity with the ipsilateral middle S1 which was mainly located within the non-atrophic area of S1.
• Our results provide neuroimaging markers for non-invasive treatment and predict somatosensory recovery.
KeywordsThalamus Stroke Magnetic resonance imaging
Central thalamic radiation
Diffusion tensor imaging
Fugl-Meyer and Lindmark Assessment
Functional magnetic resonance imaging
Montreal Neurological Institute
Primary somatosensory cortex
Primary sensorimotor cortex
White matter hyperintensities
This study was supported by the National Natural Science Foundation of China (81671666), the Doctoral Scientific Funds of North Sichuan Medical College (CBY16-QD04), Key Project Sichuan Provincial Department of Education (18ZA0211), Postgraduate Science Innovation Foundation of Chongqing (CYB16061), Fundamental Research Funds for the Central Universities (SWU1709569), and Chongqing Scientific and Technological Talents Program (kjxx2017011).
Compliance with ethical standards
The scientific guarantor of this publication is Tianyou Luo.
Conflict of interest
The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
Statistics and biometry
No complex statistical methods were necessary for this paper.
Written informed consent was obtained from all subjects in this study.
Institutional Review Board approval was obtained.
• Case-control study
• Performed at one institution
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