Search result for : author:qian xi

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Alterations of static functional connectivity and dynamic functional connectivity in motor execution regions after stroke.

The aims of this study were to examine both static functional connectivity (FC) and dynamic FC alterations in motor execution regions after stroke and to investigate whether the altered static or dynamic FC was associated with the clinical behaviors in stroke patients. Seventy-six stroke patients and 55 healthy controls (HC) were recruited. Static FC and dynamic FC maps were computed based on the seeds of six core regions in motor execution network. Correlation analyses were performed between static or dynamic FC and clinical behavioral scores in stroke patients. Compared with the HC, the stroke patients had significantly higher static FC between the seeds and the precentral or postcentral gyrus, frontal gyrus, inferior parietal lobule, thalamus and insula, and lower static FC between the seeds and the cerebellum and middle temporal gyrus. There were significant differences in dynamic FC between the seeds and precuneus, calcarine gyrus, insula, inferior parietal lobule, precentral gyrus, and middle temporal, frontal or occipital gyrus between the stroke patients and HC. Furthermore, a significant negative correlation was found between the Fugl-Meyer assessment scores and dynamic FC of the ipsilesional primary motor cortex and contralesional precentral gyrus in patients. The current study shows that the patterns of both static FC and dynamic FC changed after stroke, and correlation between motor function and temporal variability in the FC of the precentral gyrus was significant in stroke patients. Our findings indicate that dynamic FC might be a potential indicator for evaluating motor function after stroke.

Jing Chen, Dalong Sun, Yonghui Shi, Wei Jin, Yanbin Wang, Qian Xi, Chuancheng Ren
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[Assessment of preclinical cognition impairment in hypertension patients with functional magnetic resonance imaging].

To explore whether the hypertension patients with no clinical cognitive impairment manifestations have certain brain dysfunctions. Twenty-five moderately to severely hypertensive patients, males and females, aged 63.0 +/- 1.6 (60 approximately 65), with a disease history if 5 to 10 years, and 25 sex, age, and educational level-matched healthy persons underwent tests by mini-mental status examination (MMSE) scales, state anxiety inventory (STAI-S) and trait anxiety inventory (STAI-T), and then underwent two functional magnetic resonance imaging (fMRI) studies. In Experiment 1, the subjects were demanded to listen actively to the meaningless words (pseudowords) and in Experiment 2 the subjects listened actively to real words and make the valence (abstract or concrete) of the words in silence. The subjects were told to listen passively the noise from the MR scanners during the resting period, which was used as the control task. The fMRI data were analyzed with statistical parametric mapping (SPM99) software. The MMSE score of the patient group was 29.3 +/- 1.1, not significantly different from that of the control group (29.6 +/- 0.5, P > 0.05). The STAI-S score of the patient group was 47 +/- 5.3748, significantly higher than that of the control group (41.6 +/- 4.9777, P < 0.05). The STAI-S score of the patient group was 45 +/- 3, not significantly different from that of the control group (43 +/- 4, t = 1.0619, P = 0.3032). In Experiment 1, the activated patterns and deactivated patterns were nearly similar for the patient and control groups. The activated regions included the bilateral superior temporal lobe, bilateral inferior frontal cortex and supplementary motor areas. In Experiment 2, the activated patterns were also nearly similar for these 2 groups. The regions included the bilateral superior temporal lobe, bilateral inferior frontal cortex, left angular gyrus, bilateral superior frontal cortex, bilateral cerebellum, premotor areas, and supplementary motor areas. The deactivation patterns were similar for the patients and controls both in Experiment 1 and Experiment 2. These regions were medial prefrontal cortex, posterior cingulate and bilateral inferior parietal cortex, which nearly overlapping with the default model network proposed by Raichle et al. However, the activation and deactivation magnitude and extent of the brain were significantly greater for the patients than for the controls both in Experiment 1 and Experiment 2. Some brain dysfunction may have already existed in patients with moderately to severely hypertension disorders, though their behavior performance scores are within the normal range of ages. The fMRI technique can be a useful tool to detect the preclinical brain abnormalities.

Xiao-hu Zhao, Pei-jun Wang, Bing Jie, Qian Xi, Lu Gan, Tao Lei
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