| Purpose We intend to detect brain activations under Chinese semantic decision tasks with functional MRI technique. We focus on the neural networks that consist of brain regions distributed in unilateral or bilateral hemisphere and that take charge of Chinese semantic processing. Neural reorganization of aphasics is also studied. Subjects and Methods Ten healthy mandarin volunteers and three aphasics under recovery participated in this study with informed consent. Event-related design and cognitive subtraction paradigm were used in experiment. Data were acquired on GE 1.5T MR scanner, and analyzed with SPM2 software.Results The language paradigm design in this study had good specificity and reliability. Activations in the bilateral inferior frontal gyrus (BA44/45/47), middle frontal gyrus and medial frontal gyrus (BA6), bilateral parietal cortex (BA7/40), bilateral occipital cortex (BA17/18/19), left middle/inferior temporal gyrus (BA21/20) and bilateral basal ganglia regions can be found in Chinese semantic decision task. Activations involved in a Chinese semantic processing network including left prefrontal cortex (BA9/44/45/47), left temporal cortex (BA21/20/22), left fusiform (BA37) and left superior parietal cortex (BA7).Three patients all presented with increased activation in the right homologous regions. Remote effect can be seen in case1 and case2, characterized as reduced or disappeared activation in the anterior language areas with focal posterior brain lesions. Case3 with tumor originated in the left frontal language area developed a full compensation of the neural language network and without any aphasic symptoms.Conclusions (1) Bilateral distributed cortical and subcortical brain regions participate in Chinese semantic decision task. (2) Left lateralized brain regions are involved in a neural network that takes charge of Chinese semantic processing. (3) The pattern of brain activation changes in aphasics during recovery indicate reorganization of neural language network. |
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