Structural damage and functional reorganization in ipsilesional m1 in well-recovered patients with subcortical stroke.
OBJECTIVE
Both structural atrophy and functional reorganization of the primary motor cortex (M1) have been reported in patients with subcortical infarctions affecting the motor pathway. However, the relationship between structural impairment and functional reorganization in M1 remains unclear.


METHODS
Twenty-six patients exhibiting significant recovery after subcortical infarctions were investigated using multimodal MRI techniques. Structural impairment was assessed via cortical thickness, and functional reorganization was analyzed using task-evoked activation, amplitude of low-frequency fluctuation, and resting-state functional connectivity.


RESULTS
Compared with healthy controls, patients with stroke exhibited reduced cortical thickness in the ipsilesional M1; however, this region exhibited increased task-evoked activation, amplitude of low-frequency fluctuation, and resting-state functional connectivity in these patients. Patients with stroke demonstrated increased task-evoked activation in another ipsilesional M1 region, in which increased amplitude of low-frequency fluctuation and resting-state functional connectivity were observed. The structural and functional changes in M1 were located selectively in the ipsilesional hemisphere.


CONCLUSIONS
We provide convincing evidence that indicates extensive functional reorganization in the ipsilesional M1 of patients with chronic subcortical infarctions, including the structurally impaired M1 region.
From the Department of Radiology, Tianjin Key Laboratory of Functional Imaging (J.Z., L.M., W.Q., N.L., C.Y.) and Department of Neurology, Tianjin Neurological Institute (F.-D.S.), Tianjin Medical University General Hospital, Tianjin, China.
Jing
J
Zhang
Liangliang
L
Meng
Wen
W
Qin
Ningning
N
Liu
Fu-Dong
FD
Shi
Chunshui
C
Yu
D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000473:pathology; D004569:Electroencephalography; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology*; D011597:Psychomotor Performance / Q000502:physiology; D020127:Recovery of Function; D012146:Rest / Q000502:physiology; D020521:Stroke / Q000473:pathology*
cerebral infarction; functional neuroimaging; magnetic resonance imaging; motor cortex; neuronal plasticity