Done-Sik Yoo

Neural correlates related to action observation in expert archers

A growing body of evidence suggests that activity of the mirror neuron system is dependent on the observers motor experience of a given action. It remains unclear, however, whether activity of the mirror neuron system is also associated with the observers motor experience in sports game. Therefore, the aim of the present study is to investigate differences in activation of the mirror neuron system during action observation between experts and non-archer control subjects. We used video of Western-style archery in which participants were asked to watch the archery movements. Hyperactivation of the premotor and inferior parietal cortex in expert archers relative to non-archer control subjects suggests that the human mirror neuron system could contain and expand representations of the motor repertoire. The fact that dorsomedial prefrontal cortex was more active in expert archers than in non-archer control subjects indicates a spontaneous engagement of theory of mind in experts when watching video of Western-style archery. Compared with the non-archer control subjects, expert archers showed greater activation in the neural system in regions associated with episodic recall from familiar and meaningful information, including the cingulate cortex, retrosplenial cortex, and parahippocampal gyrus. The results demonstrate that expertise effects stimulate brain activity not only in the mirror neuron system but also in the neural networks related to theory of mind and episodic memory.

Alterations in cortical activity of male methamphetamine abusers performing an empathy task: fMRI study.

We investigate possible differences in neural correlates of empathy processing between abstinent methamphetamine (MA) abusers and healthy subjects using functional magnetic resonance imaging (fMRI).

Reduced corpus callosum white matter microstructural integrity revealed by diffusion tensor eigenvalues in abstinent methamphetamine addicts

The purpose of the current study was to determine whether abstinent methamphetamine (MA) abusers demonstrate differences in white matter (WM) integrity of the corpus callosum (CC) due to possible neurotoxic effects of long-term MA abuse, compared with control subjects. In addition to fractional anisotropy (FA), the eigenvalues of the diffusion ellipsoid were used to evaluate the microstructural source of abnormal change in abstinent MA abusers if there occurred a difference in white matter integrity of the CC between healthy controls and abstinent MA abusers. Results showed significantly reduced FA in the genu of the corpus callosum in MA-dependent subjects compared with controls. Furthermore, the eigenvalues offered a unique opportunity to assess the microstructural source of abnormal changes in the genu of the CC. The relationships between Wisconsin Card Sorting Test (WCST) performance and the values of tensor measures also suggest that altered myelination is a possible source of FA reduction observed in the genu of the CC in MA abusers.

The differences in neural network activity between methamphetamine abusers and healthy subjects performing an emotion-matching task: functional MRI study

Methamphetamine (MA) abusers commonly exhibit socially problematic behaviors, such as diminished empathy, decreased emotional regulation and interpersonal violence, which may be attributable to alterations in emotional experience. However, few studies have used functional MRI to examine directly the emotional experience of threatening or fearful non‐face images in MA abusers. In this study, we investigated possible differences in neural correlates of negative emotional experiences between abstinent MA abusers and healthy subjects using complex visual scenes depicting fear or threat derived from the International Affective Picture System. In within‐group analyses, healthy subjects and MA abusers activated a similarly distributed cortical network, prominently including the amygdala, fusiform gyrus, parahippocampal gyrus, ventrolateral prefrontal cortex and inferior frontal cortex. In between‐group analyses, however, MA abusers showed a reduced activation in the bilateral dorsolateral prefrontal cortex and insula, and increased activation in the fusiform gyrus, hippocampus, parahippocampal gyrus and posterior cingulate cortex, relative to healthy subjects. Hypoactivation of the insula in MA abusers relative to healthy subjects suggests that the ability to have an emotional response to threatening scenes and empathy for anothers pain could be compromised in MA abusers. Hyperactivity in the fusiform gyrus, parahippocampal gyrus and posterior cingulate cortex in MA abusers relative to healthy subjects indicates that threatening and fearful images from the International Affective Picture System may remind MA abusers of episodic memory related to similar experiences. Therefore, functional impairment of these neural networks in MA abusers may contribute to altered emotional experience in social interactions, which could lead to increased negative mood and stress in interpersonal communication. Copyright

The echotextural characteristics for the diagnosis of the liver cirrhosis using the sonographic images

Various statistical parameters have been tried for the computer-aided diagnosis of the liver fibrosis. The region of interest (ROI) for the liver and spleen parenchymas have been chosen, and the hepatolienal textural contrast for each ultrasound (US) image has been examined. The selectively chosen textural parameters are linearly combined with the pre-determined coefficients to give the computer-aided diagnostic parameter for the liver fibrosis, whose final stage is named as cirrhosis. From the comparison with the clinical diagnosis it is suggested that the proposed calculation scheme using the textural parameters show the quite promising classification performance for the computer-aided diagnosis of the liver cirrhosis.

Computer-assisted Sonographic Analysis of the Hepatorenal and Textural Features for the Diagnosis of the Fatty Liver

We investigated the B-mode ultrasound (US) images of abdomen by normalizing the gray level values of the liver with the representative gray levels (RGLs) of the liver parenchyma, renal cortex, subcutaneous fat, to quantify the fatty infiltration of the liver (FIL). The RGLs were compared with the clinical diagnosis of the FIL showing good correlation between them

A preliminary study on discrimination of osteoporotic fractured group from nonfractured group using support vector machine

Osteoporosis is characterized by an abnormal loss of bone mineral content, which leads to a tendency to non-traumatic bone fractures or to structural deformations of bone. Thus, bone density has been considered as a most reliable parameter to assess osteoporotic fracture risk. In past decades, by the way, bone texture measures have been studied to estimate other aspect of bone quality. Some studies have been performed on CT or MR images to assess bone quality using trabecular structure analysis. Other studies have been performed on plain x-ray images or ultrasound images to assess trabecular structure. However, most of the studies are focused on individual parameters to distinguish between osteoporotic fractured group and nonfractured group. In this preliminary study, we combine various texture parameters with bone density parameters using a support vector machine and point out the most promising combination of parameters to distinguish between osteoporotic fractured group and nonfractured group

Functional magnetic resonance imaging reveals age-related alterations to motor networks in weighted elbow flexion–extension movement

Abstract Objective: we investigated whether motor system activity in normal aging shows age-related alteration during a non-isomeric elbow flexion–extension movement task using weights. Methods: Twenty-six healthy, right-handed elderly and 20 healthy, right-handed young subjects without any psychiatric, neurological, or medical disease participated in this study. All subjects underwent two consecutive scanning sessions: one without weights, and one with weights. During the weights session, each subject held a small non-metallic bar (weighing approximately 1 kg) with their dominant hand and performed elbow flexion and extension movements. Functional magnetic resonance imaging BOLD contrast was obtained for each subject using a 3.0 T MRI scanner. Image processing and statistical analyses were carried out using SPM2. In fMRI data group analysis, contrast images from the analysis of individual subjects were analysed by one-sample t-tests, thereby generating a random-effects model, allowing inference to the general population. The SPM{t}s were thresholded at P<0.01, false discovery rate (FDR) corrected for multiple comparisons across the whole brain. Finally, the resulting activation maps were created and displayed by projection onto the anatomically standardized mean T1 image of all subjects to identify the anatomical correlates of the activity. Results: It was revealed that the main change in the aging brain was significant activation of the ipsilateral basal ganglia–thalamo–cortical motor loop in older subjects, suggesting the recruitment of additional brain areas during the execution of a weighted elbow motor task as a compensation process for age-related neurobiological change. Conclusion: The current study is the first to demonstrate significant differences in brain activation between old and young subjects during weighted elbow flexion–extension movement when both the old and young groups maintain the same performance level. In particular, overactivation of the basal ganglia in the aging brain appears to play a crucial role in counteracting age-related decline of force generation and to support the same level of performance as that of younger counterparts.

Present Status and Analysis for IEEE 11073 Personal Health Device Specializations

Increasing interest of life expectancy and health has made the u-health industry activating and the several international standard developing organizations(SDO) are dealing with u-health services and technologies. Among them, IEEE 11073 PHD(Personal Health Devices) Work Group is developing standards of personal health device communication for interoperability. There are many studies for introducing SDOs and analyzing the IEEE 11073-20601 standard. However, due to the rare study of PHD sta ndards analysis, there are a lot of difficulties to utilize the standards. In this paper, present status of national and international SDOs including IEEE 11073 standards for PHD will be introduced. Moreover, device specialization standards such as thermometer, weighing scale, glucose meter, blood pressure monitor, electrocardiograph (ECG) etc.. will be analyzed based on the IEEE 11073-20601.

Quantitative Analysis of White Matter on DTI Images of Patients with Tinnitus: Preliminary Report

Tinnitus is defined as an unwanted auditory perception of internal origin, usually localized, and rarely heard by others. Persisting appearances of tinnitus are most commonly combined with diseases or damage in the inner ear or neuro-auditory pathway. Diffusion tensor magnetic resonance imaging (DTI) is a new imaging method with the capability of providing non-invasive information on tissue microstructure not available in routine clinical MRI images. Since white matter regions of the brain are an ordered structure due to the myelination and directionality of axons and have a high degree of anisotropy, the ability to detect changes in anisotropy can be extremely useful in the study of diseases such as tinnitus and multiple sclerosis, which are assumed to involve the demyelination of axons. While several studies investigated tinnitus using MRI, few studies tried to analyze neurological disorders quantitatively using DTI. In this study, the cerebral volume of white matter on DTI images of patients with tinnitus was measured using the semi-automated and intuitive menu based image processing tool (Human Analyzer, ETRI, Korea). Total number of ten patients with tinnitus including three women was examined