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 another's 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.

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

OBJECTIVES: We investigate possible differences in neural correlates of empathy processing between abstinent methamphetamine (MA) abusers and healthy subjects using functional magnetic resonance imaging (fMRI). METHODS: Nineteen abstinent MA abusers (mean age of 36.06 years, range 31-52 years) and 19 healthy subjects (mean age of 37.05 years, range 33-42 years) participated in this study. A visual fMRI activation paradigm was used, comprising a series of cartoons, each depicting a short story. There were two categories of stories: empathy (Empathy) and Physical causality (Physical). fMRI images were acquired using a 3.0 T whole-body scanner. All fMRI data were analyzed using MATLAB v. 7.2 and SPM5. RESULTS: Both MA subjects and controls exhibited activation in the dorsomedial prefrontal cortex. Despite this similarity in activation patterns, we found that the two groups differed in the activation of several cortical regions associated with the processing of empathy information. Hypoactivations of the orbitofrontal cortex, temporal poles, and hippocampus in MA abusers relative to healthy subjects suggests that the ability of empathic response could be compromised in abstinent MA abusers (p < 0.05, corrected for a small volume). CONCLUSIONS: Functional impairments in the empathic neural network caused by MA may contribute to the misunderstanding of others and to the erosion of social interactions in MA abusers.

A Study of Sofa-Type Capacitive Coupling Electrocardiograph System to Measure Stress Relief for Sleeping or Resting with Oxygen Taking.

Non-contact electrode type electrocardiograph system was researched in various fields, but few products are commercially available. In this study, we proposed a sofa-type capacitive coupling electrocardiograph which has possibilities to be commercialized. The base system is a commercially available oval shape sofa that provides oxygen. We developed a capacitive coupling electrocardiograph and embedded it into the base system. The system gives feedback by measuring the ECG signal on stress relief during resting with taking oxygen provided by the sofa. In the capacitive coupling electrocardiograph, it is inevitable to develop a suitable active electrode for the target system, so we developed that comprised of a surface electrode, electronics, and metal case. The surface electrode was made of PCB with two layers of copper plate: the top layer is for coupling function (coated with AU), and the bottom layer plays a role as a shield. The fabricated active electrode module is embedded into the sofa. The purpose of the developed electrocardiograph is to measure HRV of sofa users. The measured HRV was compared with that from a reference system by various coupling distances (cotton cloth thickness) to guarantee the quality of measured signals. The comparison result shows that RRI correlation was mostly over 0.99, SDNN variation rate was mostly under 1%, and LF/HF variation rate was less than 1% in the tested thicknesses.

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 observer's motor experience of a given action. It remains unclear, however, whether activity of the mirror neuron system is also associated with the observer's 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.

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

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.

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.

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.

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.

Bone mineral density estimation using the filling factor of the radius X-ray image.

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 measurement has been considered as a most reliable method to assess bone fracture risk due to osteoporosis. In past decades, x-ray images have been studied in connection with the bone mineral density estimation. However, the estimated bone mineral density from the x-ray image can undergo a relatively large accuracy or precision error. The most relevant origin of the accuracy or precision error may be unstable x-ray image acquisition condition. In the previous study, we presented a bone mineral density estimation method that uses the trabecular bone filling factor in the radius x-ray image and that is relatively insensitive to the x-ray image acquisition condition. In this paper, we investigate the method using larger patient data and point out a preliminary result related to the fracture risk prediction using the method.

The GGO lesions detected by computer-aided detection system on chest MDCT images.

The detection of abnormal lesions in the early stages of lung cancer is important to improve survival. Computer-aided detection (CAD) system can be useful for early detection of pulmonary nodules on computed tomography (CT) images for screening. Moreover, CAD system can be 'second opinion' when a radiologist detects the pulmonary nodules on multi-slice CT images. We developed a computer-aided detection system for pulmonary nodule detection on multi-detector row computed tomography (MDCT) images. We applied the nodule isolation technique using radial distribution function and additional algorithms. In this paper, we reported the ground-glass opacity (GGO) lesions detected by self-developed computer-aided pulmonary nodule detection system.

Distal radius bone mineral density estimation using the filling factor of trabecular bone in the x-ray image.

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 measurement has been considered as a most reliable method to assess bone fracture risk due to osteoporosis. In past decades, X-ray images have been studied in connection with the bone mineral density estimation. However, the estimated bone mineral density from the X-ray image can undergo a relatively large accuracy or precision error. The most relevant origin of the accuracy or precision error may be unstable X-ray image acquisition condition. Thus, we focus our attentions on finding a bone mineral density estimation method that is relatively insensitive to the X-ray image acquisition condition. In this paper, we develop a simple technique for distal radius bone mineral density estimation using the trabecular bone filling factor in the X-ray image and apply the technique to the wrist X-ray images of 20 women. Estimated bone mineral density shows a high linear correlation with a dual-energy X-ray absorptiometry (r=0.87).

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.

The preliminary study of differentiating osteoporotic fractured group from nonfractured group.

Osteoporosis is characterized by an abnormal loss of bone mineral content, which leads to a tendency to nontraumatic bone fractures or to structural deformations of bone. Thus bone density measurement has been considered as a most reliable method to assess bone fracture risk due to osteoporosis. In past decades bone texture measures have been also studied in connection with the bone quality estimation. However, most studies have been focused on texture analysis of CT or MR images. Though studies on plain radiographs have been also performed to assess in vivo trabecular structure these studies are mainly done on anatomic sites such as femur, spine, and calcaneus. In this preliminary study we apply various texture measures to distal radius plain radiographs and point out several promising texture measures that significantly distinguish between osteoporotic fractured group and nonfractured group.

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 (RGL's) of the liver parenchyma, renal cortex, subcutaneous fat, to quantify the fatty infiltration of the liver (FIL). The RGL's were compared with the clinical diagnosis of the FIL showing good correlation between them.

The dielectric properties of cancerous tissues in a nude mouse xenograft model.

The dielectric properties of various cancers, namely brain tumor, breast cancer, gastric carcinoma, and colon cancer, were measured in the frequency range of 500 MHz to 5 GHz. Cancers were cultivated applying the xenograft model of growing human cancerous tissues using the specific pathogen free, homo inbred mouse (a nude mouse). The complex permittivity was measured using an open-ended coaxial probe (HP85070B) and a computer controlled network analyzer (HP8510C). For the measurement of the dielectric properties, a total of 58 xenografted specimens was used. The results showed that measured values of complex permittivity for all four cancerous tissues were similar, with little variations over the frequency range used. It might be agreed that components and characteristics of different cancerous tissues would be similar despite their different occurrences in the human body. It is necessary to investigate this result further.

Teratological studies of prenatal exposure of mice to a 20 kHz sawtooth magnetic field.

In order to evaluate the importance of gestational age in possible effects due to exposure to a 20 kHz sawtooth magnetic field, pregnant ICR mice at gestational 2.5-15.5 days post-coitus, which is the most sensitive stage for the induction of major congenital malformations, were exposed in a carrousel irradiator. The mice were exposed to a 20 kHz intermediate frequency (IF) sawtooth magnetic field had a 6.5 microT peak intensity for 8 h/day. The animals were sacrificed on the 18th day of gestation; and the fetuses were examined for mortality, growth retardation, changes in head size, and other morphological abnormalities. From the above conditions, it is concluded that the exposure to a 20 kHz sawtooth magnetic field with 6.5 microT peak intensity does not inflict any adverse effect on fetuses of pregnant mice.