| Purpose: To study the characteristic brain activation associated with different fordward and backward digital span by BOLD-fMRI and the difference between the mechanism involved in the two tasks at the neural level , and to explore the application value of the task in clinic. Matreial and Method: Functional magnetic resonance imaging (fMRI) on fordward and backward digits tasks of the different span (forward 2, 5, 8 digit and backword 2, 5, 8 digit respectively) in 12 in healthy voluntary, single-trial software was adopted. Images were acquired by GE 3.0T magnet including T1W image with SE sequence, Bold-fMRI images with GRE-EPI and 3D images with FSPGR. The signal changing amplitude in region of interest(ROI) were counted using AFNI. Repeated Measures ANOVA was applied to analyze the interaction between the task category and load in the group, and further to analyze the data involved in task category (forword and backword) and load (2,5 and 8digit). Results: (l)There are many areas showed more activation in the tasks backward 5 vs forward 5 digit group, forward 8 vs 5 digit group and backward 5 vs 2 digit group including SMA, left BA 6, left DLPFC, left parietal lobe, occipital visual lobe, both dorsal caudate putamen, left Broca, and additional both MTL in backward 5 vs forward 5 digit group, Wernick' s area in forward 8 vs 5 digit group and backward 5 vs 2 digit group. (2) The activation increased in the occipital visual lobe, left parietal lobe and Wernick's area in task of backward 8 vs forward 8 digit, and more activation in the occipital visual lobe, left DLPFC and Wernick' s area in task of backward 8 vs 5 digit group. (3)No significant different activation in the backward 2 vs forward 2 digit , forward 2 vs 5 digit groups. (4) The medial PFC and precuneate lobe showed contrary effect in the task of forward-backward and digit load. Conclusion: Both digital forward and digital backward rely on a largely overlapping functional neural system associated with language working memory and the degree of activation in some regions increased linearly with increasing forward task diffi culty. The digits backward memory wasclosely correlated with the frontal lobe and the task of digits memory can be better model by fMRI in the clinical application. Part II A fMRI Study of damaged Digital Working Memory 1 month after traumaticfrontal lobe injuryPurpose: To examine the brain activation while performing a digital working memory in persons with traumatic frontal lobe injury after 1 month by fMRI . To study the correlation between the activated changes and focal lesion in frontal lobe and to investigate the neural mechanism behind it and the feasibility in TBI research. Matreial and Method: FMRI was used to assess brain activation during a forword and backword digital span working memory task in 10 patients with TBI and 12 healthy controls, single-trial software was adopted. Images were acquired by GE 3.0T magnet including T1W image with SE sequence, Bold-fMRI images with GRE-EPI and 3D images with FSPGR. The signal changing amplitude in region of interest(ROI) were counted using AFNI. Repeated Measures ANOVA was applied to analyze the interaction between the task category and load or interclass, and further to analyze the data about task category (forword and backword) and load (2 digital and 4digital ) within groups and interclass between the controls and patients. Results: The activation increased in both DLPFC and parietal lobe, left Broca and left angular gyrus in healthy controls comparing with backword 4 and forward 4 digital task, but only left occipital lobe showed more activation in patients with backword 4 comparing forward 4 task. The healthey controls showed stronger activation in left DLPFC, left angular gyrus(backward 4 task) and left occipital lobe , right angular gyrus (forward 4 task) than patients, and the patients showed more activation in right motor area, cuneate lobe(backward 4 task) and right Broca and frontal pole (forward 4 task) than healthy controls . Conclusion: Frontal lobe is the key point in the working memory net, and the memory function was damaged in the early periodafter the damaged frontal lobe. The right hemisphere can provide great compensation resource when needed in the net. FMRI can explore the neural mechanism after TBI, and supply cognitive impaired evidence in neuroimage information,there is some difficulty in TBI research. Part IE The Study of cortical reorganization with Working memoryDuring later TBI periodPurpose: To study the characteristic activation while performing a digital working memory in TBI persons during their later recovery period. To explore the underlying mechanism in the plascity changes after traumatic frontal lobe injury by fMRI and To investigate the value of fMRI to detect working memory injury rehabilitation. Matreial and Method: FMRI was used to assess brain activation during a forword and backword digital span working memory task in 8 patients with TBI during later recovery period and 12 healthy controls, single-trial software was adopted. Images were acquired by GE 3.0T magnet including T1W image with SE sequence, Bold-fMRI images with GRE-EPI and 3D images with FSPGR. The signal changing amplitude in region of interest(ROI) were counted using AFNI. Repeated Measures ANOVA was applied to analyze the interaction between the task category and load or interclass, and further to analyze the data about task category (forword and backword) and load (2 digits and 4digits) within groups and interclass between the controls and patients. Results: (1)The activation increased in both DLPFC and parietal lobe, left Broca and left angular gyrus in healthy controls comparing with backword 4 and forward 4 digital span. (2)Right parietal lobe and left angular gyrus showed more activation in patients with forward 4 digits vs 2 digits group. (3)The patients showed stronger activation in left MA, both DLPFC, both parietal lobe, left angular gyrus, left basal area, right MA, right Broca, right frontal pole and precuneate in forward 4 digits task and right DLPFC, right Broca and precuneate in backward 4 digits task than healthy controls . Conclusion: Working memory was damaged in nature recovery after frontallobe injury, the brain showed obvious side effect during later period. FMRI can discover the reorganization of the memory system and have the potential value in guiding the rehabilitation treatment.
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