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ABSTRACT: The corpus callosum (CC) has emerged as one of the primary targets of autism research. To detect aberrant CC interhemispheric connectivity in autism, we performed T1-weighted magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI)-based tractography in 18 children with high functioning autism (HFA) and 16 well-matched typically developing (TD) children. We compared global and regional T1 measures (CC volume, and CC density), and the DTI measures [fractional anisotropy (FA), apparent diffusion coefficient (ADC), average fiber length (AFL), and fiber number (FN)] of transcallosal fibers, between the two groups. We also evaluated the relationships between scores on the Childhood Autism Rating Scale (CARS) and CC T1 or DTI measurements. Significantly less white matter density in the anterior third of the CC, and higher ADC and lower FN values of the anterior third transcallosal fiber tracts were found in HFA patients compared to TD children. These results suggested that the anterior third CC density and transcallosal fiber connectivity were affected in HFA children.
Psychiatry Research 10/2011; 194(3):333-9. · 2.52 Impact Factor
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Xiaoyan Ke,
Tianyu Tang,
Shanshan Hong,
Yueyue Hang,
Bing Zou,
Huiguo Li,
Zhenyu Zhou, Zongcai Ruan,
Zuhong Lu,
Guotai Tao,
Yijun Liu
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ABSTRACT: This study explored white matter abnormalities in a group of Chinese children with high functioning autism (HFA). Twelve male children with HFA and ten matched typically developing children underwent diffusion tensor imaging (DTI) as well three-dimensional T1-weighted MRI for voxel-based morphometry (VBM). We found a significant decrease of the white matter density in the right frontal lobe, left parietal lobe and right anterior cingulate and a significant increase in the right frontal lobe, left parietal lobe and left cingulate gyrus in the HFA group compared with the control group. The HFA group also had decreased FA in the frontal lobe and left temporal lobe. By combining DT-MRI FA and MRI volumetric analyses based on the VBM model, the results showed consistent white matter abnormalities in a group of Chinese children with HFA.
Brain research 03/2009; 1265:171-7. · 2.46 Impact Factor
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ABSTRACT: In this paper we present a model based method for fast face orientation estimation and pose recovery from a monocular image sequence captured by an uncalibrated camera. To accomplish this method, CANDIDE-3 model is used to construct 3D individual face model manually. Four facial feature points (outer corners of eyes and mouth) are tracked by SIFT algorithm. Taking advantage of these feature points and 3D individual face model, facial pose recovery can be quickly completed with a Fast Face Orientation Estimation Algorithm. An experimental system has been built to carry out the estimation method. The estimation results are robust and flexible.
Image and Signal Processing, 2008. CISP '08. Congress on; 06/2008
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ABSTRACT: Functional near-infrared spectroscopy (fNIRS) is a non-invasive method for studying functional activation via monitoring changes of the hemodynamic properties in brain and event-related experimental in examining cognitive processes is very useful but much more flexible in data analysis. To validate the usefulness of independent component analysis (ICA) of event-related fNRIS data, a "high-motivation" GKT (guilty knowledge test) task was applied. A very efficient method of maximization suited called FastICA was applied to maximize the contrast function in practice. Compared with the fMRI studies of ICA, the oxy-HB (oxygenated hemoglobin) signals can be decomposed and the active areas can be found in emotional behavior. The time courses and active regions of the event-related ICA components were consistent across trials. ICA approach delivers valid fNIRS amplitude estimations and enables the analysis of event-related fNIRS data series which are highly relevant in particular for cognitive fNIRS studies.
BioMedical Engineering and Informatics, 2008. BMEI 2008. International Conference on; 06/2008
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Xiaoyan Ke,
Shanshan Hong,
Tianyu Tang,
Bing Zou,
Huiguo Li,
Yueyue Hang,
Zhenyu Zhou, Zongcai Ruan,
Zuhong Lu,
Guotai Tao,
Yijun Liu
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ABSTRACT: Earlier studies have suggested abnormal brain volumes in autism, but inconsistencies exist. Using voxel-based morphometry, we compared global and regional brain volumes in 17 high-functioning autistic children with 15 matched controls. We identified significant reduction in left white matter volume and white/gray matter ratio in autism. Regional brain volume reductions were detected for right anterior cingulate, left superior parietal lobule white matter volumes, and right parahippocampal gyrus gray matter volume, whereas enlargements in bilateral supramarginal gyrus, right postcentral gyrus, right medial frontal gyrus, and right posterior lobe of cerebellum gray matter in autism. Our findings showed global and regional brain volumes abnormality in high-functioning autism.
Neuroreport 06/2008; 19(9):921-5. · 1.66 Impact Factor
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ABSTRACT: A novel segmentation method based on wavelet transform is presented for gray matter, white matter and cerebrospinal fluid in thin-sliced single-channel brain magnetic resonance (MR) scans. On the basis of the local image model, multicontext wavelet-based thresholding segmentation (MCWT) is proposed to classify 2D MR data into tissues automatically. In MCWT, the wavelet multiscale transform of local image gray histogram is done, and the gray threshold is gradually revealed from large-scale to small-scale coefficients. Image segmentation is independently performed in each local image to calculate the degree of membership of a pixel to each tissue class. Finally, a strategy is adopted to integrate the intersected outcomes from different local images. The result of the experiment indicates that MCWT outperforms other traditional segmentation methods in classifying brain MR images.
Magnetic Resonance Imaging 05/2007; 25(3):381-5. · 1.99 Impact Factor
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ABSTRACT: Presentation of negative pictures was used as emotional stress to assess gender differences in prefrontal area activation in a functional near-infrared spectroscopy (NIRS) study. Compared with neutral condition, the response of oxy-HB for men yielded no significant difference during stress period, but the response induced by stress pictures for women showed significant enhancement. It was indicated that it is crucial to take gender difference into account when negative stimuli are used in functional brain imaging.
Behavioural Brain Research 04/2007; 178(1):172-6. · 3.42 Impact Factor
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ABSTRACT: In this paper, we present a novel approach to estimate the human's eye gaze from a single infrared spectrum image of two eyes. Observing that the pupil contour is a circle, we estimate the normal direction of this circle, considered as the eye gaze, from its elliptical image. By assuming that the two gaze vectors of both eyes and the vector which is determined by the two centers of the right and left pupil are coplanar, we can calculate the both eye gaze. Compared to most existing 3-D gaze estimation algorithms, our approach does not require those of face feature information such as the eye corners. Since the focal length can be calculated by our "Coplanar Constraint", ours does not need to know the exact focal length of the camera. The extensive experiments over simulated images and real images demonstrate the feasibility and the effectiveness of our method.
Software Engineering, Artificial Intelligence, Networking, and Parallel/Distributed Computing, 2007. SNPD 2007. Eighth ACIS International Conference on;
