The Role Of Cortico-Thalamo-Cortico Loops In Cortical Functional Reorganization After Acute Stroke

This graduation thesis using ReHo method to investigate the thalamic involvement in cortical functional reorganization after acute stroke in resting state functional magnetic resonance imaging(rsfMRI) data.Previous studies have suggested that cortical functional reorganization is related to motor recovery following stroke and motor recovery after stroke was along with changes of the thalamic involvement. And, the thalamus may also play a critical role in harmonizing the activity among different cortical areas by Cortico-Thalamo-Cortico Loops. But, the role of Cortico-Thalamo-Cortico Loops in the cortical functional reorganization after stroke were unclear.To investigate whether the Cortico-Thalamo-Cortico Loops play a role in cortical functional reorganization after stroke, we divided stroke patients into two groups:UP group-the Cortico-Thalamo-Cortico Loops were normal(the sensory information from thalamus was normal (n=16)); DOWN group-the Cortico-Thalamo-Cortico Loops were abnormal(the sensory information from thalamus was dysfunctional (n=10)). Then, we investigated the difference of regional homogeneity (ReHo) between two groups of patients and healthy controls (n=19) using resting functional magnetic resonance imaging data.Results showed that compared with healthy controls, there were significantly increased ReHo in the thalamus and memory associated regions including the right/left parahippocampal gyrus and significantly decreased ReHo in the sensory integration associated areas including left cuneus/precuneus and left middle temporal gyrus in UP group. Significantly decreased ReHo in the bilateral cuneus/precuneus and right inferior parietal lobule but increased ReHo in no brain areas were found in DOWN group. The functional connectivity with 1-thalamus were higher in 1-medial frontal gyrus, r-fusiform gyrus and r-middle temporal than H group in UP group while only higher in 1-medial frontal gyrus in DOWN group. And we found no topological properties were different significantly between UP/DOWN and healthy group.Our results might suggest that compensatory changes in the memory system due to the dysfunction of somatosensory in stroke patients only happened when the Cortico-Thalamo-Cortico Loops were normal and this effect may affect a specific thalamus network instead of the whole brain functional networks.Conclusions:Our result may suggest that a better cortical functional reorganization has happened in the stroke patients whose Cortico-Thalamo-Cortico Loops were normal and this result suggest that the Cortico-Thalamo-Cortico Loops might play a critical role in the cortical functional reorganization after stroke. The approach in our study might supply a new study method. Moreover, the Cortico-Thalamo-Cortico Loops in cortical functional reorganization after stroke may suggest a new direction in clinical treatment after stroke.