Brain activation regions in schizophrenia patients performing the game piece memory task

BACKGROUND： Go, a traditional Chinese chess-like game, requires many unknown functions of the brain including attention, imaging, problem solving and processing of spatial working memory. To date, it remains uncertain whether the intellectual activities required to play Go are related to the frontal lobe. OBJECTIVE： To investigate various patterns of brain region activity while schizophrenic patients and normal subjects engaged in memorizing piece placement in the Chinese game of Go. Spatial working memory was measured in order to validate whether the prefrontal lobe participates in this memory process. DESIGN, TIME AND SETTING： Non-randomized, concurrent control trial was performed at Second Xiangya Hospital of Central South University, between May and December 2004. PARTICIPANTS： A total of nine Chinese schizophrenic patients with no brain or bodily diseases and not undergoing electroshock treatment, who were in accordance with the DSM-Ⅳ criteria for schizophrenia, as well as thirteen healthy staffs and students with matched age, sex, and education were included. Patients and control subjects had no neurological disorders or mental retardation. In addition, all participants were right-handed. METHODS： The cognitive task for functional magnetic resonance imaging was a block design experiment. Both groups were asked to remember the placement of pieces in the Chinese game of Go on a computer screen. A brain activation map was analyzed in SPM99. MAIN OUTCOME MEASURES： Brain responses were compared with regard to activation region size, volume, and asymmetry indices. RESULTS： Compared with the control group, the reaction time was significantly delayed in schizophrenics performing the working memory task （P 〈 0.05）. When performing the tasks, normal subjects showed significant activation of the bilateral dorsolateral prefrontal lobe with left dominance; the asymmetry indices were： frontal lobe, ＋0.32; temporal lobe, 0.58; parietal lobe, 0.41 ; and occipital lobe, 0.34. On the other hand, schizophrenics showed right dominance and had a broader activation region of the prefrontal lobe （asymmetry indices： frontal lobe, 0.10; temporal lobe, ＋0.38; parietal lobe, ＋0.24; and occipital lobe, 0.00）. When comparing the normal group subtracted with the schizophrenic group, no significant lateralization was found in the frontal lobes but significant activation was found in the left anterior central gyrus, left middle frontal gyrus and in both sides of the cingulate gyrus. Comparing the schizophrenic group subtracted with the normal group, there was significant right lateralization of the frontal lobe and abnormally activated regions on both sides of the anterior central gyrus, middle frontal gyrus, left inferior frontal gyrus, right medial frontal gyrus and the right insular lobe. CONCLUSION： Different brain activation regions are involved in memorizing the placement of pieces in Chinese Go between schizophrenia and healthy subjects. Schizophrenics showed right dominance and border activation range, indicating that the prefrontal cortex plays an important role in memory information processing and resource allocation when remembering piece placement in the game of Go.

Right anterior cingulate gyrus in encephalic region associated with integrating and processing Chinese words information in working memory: A functional magnetic resonance imaging study

BACKGROUND ： Many experimental results have been found in previous studies on whether laterality of brain cingulate gyrus exists in processing Chinese words information. OBJECTIVE ： To observe the function of right anterior cingulate gyrus and activation showed by MRI in processing Chinese words in a visual working memory judgment tasks, and evaluate the laterality of activated brain regions. DESIGN ： Observation experiment SETTING ： The Medical Psychological Research Center, Second Xiangya Hospital of Central South University.PARTICIPANTS： Thirteen healthy volunteers （7 males and 6 females）, aged （29±7）years ranging from 23 to 36 years old, participated in this fMRI study dunng August 2003 to Febuary 2004. They gave informed consent in accordance with guidelines set by Second Xiangya Hospital of Central South University. All subjects were native Chinese speakers and strongly right handed. METHODS ： In this study, Chinese numeral words were used as test materials and test mode of Sternberg was used in cognitive task, it was aimed to investigate the encephalic region involved in the storage and processing of Chinese numerical information. ①The head of subject was fixed with dense foam pad. Visual working task was performed according to the requests. Verbal working task was that the subject saw target items for four numerals written in Chinese, presenting for 1.5 s and then, after a short time by blank for 3.0 s. The subject saw one numeral presenting for 1.5 s and had to press one button if it was one of the shown numbers and another button if it did not belong to the presented numbers. There were two visual working memory stimuli in each stimulation block. The experiment was conducted in a single run, which consisted of seven blocks of visual working memory tasks. Different Chinese numerals were displayed in each block to avoid any practice effect （The response rate of the whole working memory task was 50%）. ②The activation of brain was scanned with a 1.5T MRI scanner （GE Signa Twinspeed） （slice thickness 5 mm, slice gap 1.5 mm, slice parallel to line between pars geniculate and splenium in corpus callosum from corona capitis to superior part of cerebellum, totally 16 to 18 layers）. ③The obtained images were pre-processed and statistically analysed with SPM 99 software. The procedure included timeslice adjusted, realigned, nomalized and smoothed, According to experimental task, data from each subject were analysed to obtain t value of each voxel. Brain activation image was got by Student＇s t test and statistic was presented by pseudo-color. Statistical parameter image was formed by overlapping brain activation image on three-dimensional structure image, and the threshold value was set at P〈 0.05 with ten or more continous voxels （T ≥ 4.64, K ≥ 10 voxels）. The brain activation images of all the subjects were calculated and overlapped into mean brain activation images. The regions with different activation density were found out. The activation voxels in regions-of-interest were checked to calculate a laterality index for each condition. The negative value indicated right hemisphere dominance. MAIN OUTCOME MEASURES ： fMRI activation and laterality coefficient of Chinese numedal working task.RESULTS： Thirteen healthy subjects participated in the result analysis. ①fMRI activation of Chinese numerial working task： The results showed that the working memory task with Chinese words not only activated left cerebral cortex including left superior frontal gyrus （BA6/10）, left middle frontal gyrus （BA9）, left inferior frontal gyrus （BA45/9/47）, but also activated right cerebral cortex including right middle frontal gyrus （BA10/46/8）, right inferior frontal lobe （BA47）. Specially, peak activation was located in right anterior cingulate gyrus （BA32） with an activation volume of 879 （voxels）. It indicated that superior, middle and inferior frontal gyrus, bilateral Broca regions and anterior cingutate involved in the working memory of Chinese words. ②Asymmertry index ： The asymmetry index was -0.47 for frontal lobe, ＋0.42 for temporal lobe, ＋0.14 for parietal lobe and -1.00 for occipital lobe. It indicated that the right frontal lobe, left temporal lobe, left parietal lobe and dght occipital lobe were more involved in the Chinese numedal working task.

Classification of schizophrenic patients and healthy controls using multiple spatially independent components of structural MRI data

Several meta-analyses were recently conducted in attempts to identify the core brain regions exhibiting pathological changes in schizophrenia,which could potentially act as disease markers.Based on the findings of these meta-analyses,we developed a multivariate pattern analysis method to classify schizophrenic patients and healthy controls using structural magnetic resonance imaging(sMRI)data.Independent component analysis(ICA)was used to decompose gray matter density images into a set of spatially independent components.Spatial multiple regression of a region of interest(ROI)mask with each of the components was then performed to determine pathological patterns,in which the voxels were taken as features for classification.After dimensionality reduction using principal component analysis(PCA),a nonlinear support vector machine(SVM)classifier was trained to discriminate schizophrenic patients from healthy controls.The performance of the classifier was tested using a 10-fold cross-validation strategy.Experimental results showed that two distinct spatial patterns displayed discriminative power for schizophrenia,which mainly included the prefrontal cortex(PFC)and subcortical regions respectively.It was found that simultaneous usage of these two patterns improved the classification performance compared to using either of them alone.Moreover,the two pathological patterns constitute a prefronto-subcortical network,suggesting that schizophrenia involves abnormalities in networks of brain regions.

Processing real-world imagery with FACADE-based approaches

This paper considers the processing of realworld imagery in the so-called Form-And-Color-And-DEpth(FACADE)framework,which features some superior mechanisms of the human vision system(HVS).FACADE framework was originally proposed by Grossberg et al.as an integrative model of the HVS to illustrate the possible procedures for visual perception of shape(the boundary contour),surface(luminance and color),and binocular depth.As a simplified,reasonable and mathematically full-fledged approach to the HVS,we saw FACADE as a promising infrastructure through which to construct a powerful image processing engine.However,in our attempts to use the approach in its original modality,to deal with real-world imagery,we found it to be inefficient and non-robust.After re-introducing the model hierarchy and illustrating the involved cell dynamics of the FACADE framework,this paper reveals the crucial issues that lead to the deficiency and accordingly present our substitutive solutions by incorporating the mechanisms of anisotropic spatial-and diffusive orientational-competition to make the HVS-featured model efficient and robust.A computer system based on the improved FACADE engine has been implemented and tested not only with illustrative images to highlight the model characteristics,but also with some real-world imagery in both monocular and binocular situations,thereby demonstrating the ability of the FACADE-based image processing approach featuring the HVS.