Gwang-Won Kim

Human brain activation in response to visual stimulation with rural and urban scenery pictures: a functional magnetic resonance imaging study.

Human brain activation was assessed in terms of eco-friendliness while viewing still photographs depicting rural and urban surrounding environments with the use of a functional magnetic resonance imaging technique. A total of 30 subjects who had both rural and urban life experiences participated in this study. In order to explore the common and differential activation maps yielded by viewing two extreme types of scenery, random effect group analysis was performed with the use of one-sample and two-sample t-tests. Activation of the anterior cingulate gyrus, globus pallidus, putamen and head of the caudate nucleus was dominant during rural scenery viewing, whereas activation of the hippocampus, parahippocamus and amygdala was dominant during urban scenery viewing (p<0.01). These findings allow better characterization of neural activation, suggesting an inherent preference towards nature-friendly living. Such a theoretical acquisition may have an important practical impact in view of potential applications for bio-housing and the development of environmental psychology-related areas.

Time-Course Analysis of the Neuroanatomical Correlates of Sexual Arousal Evoked by Erotic Video Stimuli in Healthy Males

Objective To assess the dynamic activations of the key brain areas associated with the time-course of the sexual arousal evoked by visual sexual stimuli in healthy male subjects. Materials and Methods Fourteen right-handed heterosexual male volunteers participated in this study. Alternatively combined rest period and erotic video visual stimulation were used according to the standard block design. In order to illustrate and quantify the spatiotemporal activation patterns of the key brain regions, the activation period was divided into three different stages as the EARLY, MID and LATE stages. Results For the group result (p < 0.05), when comparing the MID stage with the EARLY stage, a significant increase of the brain activation was observed in the areas that included the inferior frontal gyrus, the supplementary motor area, the hippocampus, the head of the caudate nucleus, the midbrain, the superior occipital gyrus and the fusiform gyrus. At the same time, when comparing the EARLY stage with the MID stage, the putamen, the globus pallidus, the pons, the thalamus, the hypothalamus, the lingual gyrus and the cuneus yielded significantly increased activations. When comparing the LATE stage with the MID stage, all the above mentioned brain regions showed elevated activations except the hippocampus. Conclusion Our results illustrate the spatiotemporal activation patterns of the key brain regions across the three stages of visual sexual arousal.

Neuroanatomical Mechanism on the Effect of Distraction in Working Memory Maintenance in Patients With Schizophrenia

This study utilized functional magnetic resonance imaging (fMRI) to discriminate brain activation patterns associated with the effect of distraction during working memory (WM) maintenance for human faces in healthy controls and patients with schizophrenia. Event-related fMRI data were obtained while the subjects performed WM maintenance in a delayed-response WM task with task-irrelevant distracters. Compared with healthy controls, patients showed significantly decreased activities in the superior frontal gyrus, dorsolateral prefrontal cortex (DLPFC), ventrolateral prefrontal cortex, anterior cingulate cortex, inferior parietal gyrus, and fusiform gyrus during the delayed-response WM task with human face distracters. The blood-oxygen-level-dependent signal changes in the DLPFC were negatively correlated with both of the scores of the Positive Subscale and General Psychopathology Subscale under the Positive and Negative Syndrome Scale during the WM maintenance for the human faces in the patients. This study will be helpful in understanding the neural mechanisms in the general impairment of the inhibition control in schizophrenia.

Brain Activation in Response to Visually Evoked Sexual Arousal in Male-to-Female Transsexuals: 3.0 Tesla Functional Magnetic Resonance Imaging

Objective This study used functional magnetic resonance imaging (fMRI) to contrast the differential brain activation patterns in response to visual stimulation with both male and female erotic nude pictures in male-to-female (MTF) transsexuals who underwent a sex reassignment surgery. Materials and Methods A total of nine healthy MTF transsexuals after a sex reassignment surgery underwent fMRI on a 3.0 Tesla MR Scanner. The brain activation patterns were induced by visual stimulation with both male and female erotic nude pictures. Results The sex hormone levels of the postoperative MTF transsexuals were in the normal range of healthy heterosexual females. The brain areas, which were activated by viewing male nude pictures when compared with viewing female nude pictures, included predominantly the cerebellum, hippocampus, putamen, anterior cingulate gyrus, head of caudate nucleus, amygdala, midbrain, thalamus, insula, and body of caudate nucleus. On the other hand, brain activation induced by viewing female nude pictures was predominantly observed in the hypothalamus and the septal area. Conclusion Our findings suggest that distinct brain activation patterns associated with visual sexual arousal in postoperative MTF transsexuals reflect their sexual orientation to males.

A comparative study of brain activation patterns associated with sexual arousal between males and females using 3.0-T functional magnetic resonance imaging

UNLABELLED Background In contrast to the previous studies using a 1.5-T magnetic resonance imaging system, our study was performed on a higher magnetic field strength, 3.0 T, to gain more valuable information on the functional brain anatomy associated with visual sexual arousal for discriminating the gender difference by increasing the detection power of brain activation. METHODS Twenty-four healthy subjects consisting of 12 males and 12 females underwent functional magnetic resonance imaging examination for this study. Brain activity was measured while viewing erotic videos. RESULTS The predominant activation areas observed in males as compared with females included the hypothalamus, the globus pallidus, the head of the caudate nucleus, the parahippocampal gyrus, the amygdala and the septal area, whereas the predominant activation in females was observed in the anterior cingulate gyrus and the putamen. CONCLUSION Our findings suggest that the brain activation patterns associated with visual sexual arousal are specific to gender. This gender difference in brain activation patterns is more remarkable at higher magnet field (3.0 T) than at 1.5 T.

Emotional effect on cognitive control in implicit memory tasks in patients with schizophrenia.

The aim of this study was to reveal a potential effect of emotion on cognitive control in the implicit memory task with emotionally neutral and unpleasant words in healthy controls and patients with schizophrenia using a 3.0 T functional MRI (fMRI). A total of 15 patients with schizophrenia and 15 healthy controls underwent the fMRI. fMRI data were obtained while the participants performed the implicit memory tasks with emotionally neutral and unpleasant words. During the implicit memory retrieval with emotionally neutral words, the predominant activation areas observed in patients in contrast to healthy controls included the precuneus, superior parietal gyrus, and dorsolateral prefrontal cortex (dlPFC). In the implicit memory retrieval with unpleasant words, patients with schizophrenia showed dominant activities in the superior and middle temporal gyri, fusiform gyrus, supramarginal gyrus, postcentral gyrus, occipital gyrus, lingual gyrus, parahippocampal gyrus, amygdala, and insula as well as precuneus, superior parietal gyrus, and dlPFC. Blood-oxygen-level-dependent signal changes in the dlPFC were correlated positively with the scores of the negative symptoms under the PANSS during implicit memory retrieval with unpleasant words in patients with schizophrenia. These findings would be useful to understand the neural mechanisms related to general impairment of cognitive and emotional functions commonly observed in schizophrenia.

Whole brain volume changes and its correlation with clinical symptom severity in patients with schizophrenia: A DARTEL-based VBM study

The purpose of this study was to evaluate gray matter (GM) and white matter (WM) volume alterations in whole-brain structures in patients with schizophrenia and healthy controls using voxel-based morphometry (VBM), and further to assess the correlation between GM and WM volume variations and symptom severity in schizophrenia. A total of 22 patients with schizophrenia and 22 age-matched healthy controls participated. Magnetic resonance image data were processed using SPM8 software with diffeomorphic anatomical registration via an exponentiated Lie algebra (DARTEL) algorithm. Patients with schizophrenia exhibited significantly decreased GM volumes of the insula, superior temporal gyrus (STG), gyrus rectus, and anterior cingulate cortex (ACC) compared with healthy controls. The GM volumes of the STG and gyrus rectus were negatively correlated with the positive scales on the Positive and Negative Syndrome Scale (PANSS) and those of the STG and ACC were negatively correlated with the negative scales. The durations of illness in schizophrenia were negatively correlated with the GM volumes of the insula, STG, and ACC. Patients with schizophrenia exhibited significantly decreased WM volumes of the superior frontal gyrus, inferior temporal gyrus, and STG. The WM volumes of the STG were negatively correlated with the duration of illness. Our findings suggest that GM and WM volume abnormalities in the STG are associated with the psychopathology of schizophrenia.

Noninvasive biomarkers for acute hepatotoxicity induced by 1,3-dichloro-2-propanol: hyperpolarized 13C dynamic MR spectroscopy

The purpose of this study was to investigate the cellular metabolite change for acute hepatotoxicity induced by 1,3-dichloro-2-propanol (1,3-DCP) in rats and its correlations with the enzyme levels. In order to induce acute hepatotoxicity, a single subcutaneous injection of 1,3-DCP (80 mg/kg) was given to six male Sprague-Dawley rats. Hyperpolarized (13)C dynamic magnetic resonance spectroscopy (MRS) was performed on rat liver following injection of hyperpolarized [1-(13)C] pyruvate. The levels of serum aspartate am inotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) in the 1,3-DCP treated rats were significantly increased as compared with those in normal rats. In the dynamic (13)C MR spectra, the ratios of [1-(13)C] lactate to the total carbon and [1-(13)C] alanine to the total carbon in the 1,3-DCP treated rats were significantly increased, and there were positive correlations between cellular metabolic changes and enzyme levels. The levels of [1-(13)C] lactate and [1-(13)C] alanine are potentially considered as important biomarkers for the 1,3-DCP-induced acute hepatotoxicity.

Effects of Antidepressant Treatment on Sexual Arousal in Depressed Women: A Preliminary fMRI Study

Objective There was a recent study to explore the cerebral regions associated with sexual arousal in depressed women using functional magnetic resonance imaging (fMRI). The purpose of this neuroimaging study was to investigate the effects of antidepressant treatment on sexual arousal in depressed women. Methods Seven depressed women with sexual arousal dysfunction (mean age: 41.7±13.8, mean scores of the Beck Depression Inventory (BDI) and the 17-item Hamilton Rating Scale for Depression (HAMD-17): 35.6±7.1 and 34.9±3.1, respectively) and nine healthy women (mean age: 40.3±11.6) underwent fMRI before and after antidepressant treatment. The fMRI paradigm contrasted a 1 minute rest period viewing non-erotic film with 4 minutes of sexual stimulation viewing an erotic video film. Data were analyzed by SPM 2. The relative number of pixels activated in each period was used as an index of activation. All depressed women were treated with mirtazapine (mean dosage: 37.5 mg/day) for 8 to 10 weeks. Results Levels of brain activity during sexual arousal in depressed women significantly increased with antidepressant treatment (p<0.05) in the regions of the hypothalamus (3.0% to 11.2%), septal area (8.6% to 27.8%) and parahippocampal gyrus (5.8% to 14.6%). Self-reported sexual arousal during visual sexual stimulation also significantly increased post-treatment, and severity of depressive symptoms improved, as measured by the BDI and HAMD-17 (p<0.05). Conclusion These results show that sexual arousal dysfunction of depressed women may improve after treatment of depression, and that this improvement is associated with increased activation of the hypothalamus, septal area, and parahippocampal gyrus during sexual arousal.

Menopause-related brain activation patterns during visual sexual arousal in menopausal women: An fMRI pilot study using time-course analysis

The aging process and menopausal transition are important factors in sexual dysfunction of menopausal women. No neuroimaging study has assessed the age- and menopause-related changes on brain activation areas associated with sexual arousal in menopausal women. The purpose of this study was to evaluate the time course of regional brain activity associated with sexual arousal evoked by visual stimulation in premenopausal and menopausal women, and further to assess the effect of menopause on the brain areas associated with sexual arousal in menopausal women using functional magnetic resonance imaging (fMRI). Thirty volunteers consisting of 15 premenopausal and 15 menopausal women underwent the fMRI. For the activation condition, volunteers viewed sexually arousing visual stimulation. The brain areas with significantly higher activation in premenopausal women compared with menopausal women included the thalamus, amygdala, and anterior cingulate cortex (ACC) using analysis of covariance adjusting for age (p<0.005). Blood-oxygen-level-dependent signal changes in the amygdala while viewing erotic video were positively correlated with estrogen levels in the two groups. Our findings suggest that reduced brain activity of the thalamus, amygdala, and ACC in menopausal women may be associated with menopause-related decrease in sexual arousal. These findings might help elucidate the neural mechanisms associated with sexual dysfunction in menopausal women.