• Journal of radiological science and technology
• /
• v.34 no.1
• /
• pp.17-25
• /
• 2011

In this study, we examined the impact caused by chronic exposure to Mn by investigating the degree of brain activation based on the data of recognition activities using fMRI (functional magnetic resonance imaging). A questionnaire survey, blood tests, and fMRI tests were carried out with respect to two groups. Group 1 was an exposure group consisting of 15 male workers who are 34 years old or older, and who worked for longer than 10 years in a shipbuilding factory as a welder. Group 2 was a control group consisting of 15 workers in manufacturing industries with the same gender and age. The results showed that blood Mn concentration of Group 1($1.3\;{\mu}g/dl$) was significantly higher than that of Group 2($0.8\;{\mu}g/dl$)(p < 0.001), and Pallidal Index (PI) of Group 1 was also significantly higher than that of Group 2 (p < 0.001). PI value of the group whose blood Mn concentration was $0.93\;{\mu}g/dl$ or higher was significantly higher than that of the group whose blood Mn concentration was less than $0.93 \;{\mu}g/dl$ (p < 0.001). As for brain activity area within the control group, the right and the left areas of occipital cortex showed significant activity and the left area of middle temporal cortex, the right area of superior inferior frontal cortex and inferior parietal cortex showed significant activity. Unlike the control group, the exposure group showed significant activity on the right area of superior inferior temporal cortex, the left of insula area. In the comparison of brain activity areas between the two groups, the exposure group showed significantly higher activation than the control group in such areas as the right inferior temporal cortex, the left area of superior parietal cortex and occipital cortex, and cerebellum including middle temporal cortex. However, in nowhere the control group showed more activated area than the exposure group. As the final outcome, chronic exposure to Mn increased brain activity during implementation of arithmetic task. In an identical task, activation increased in superior inferior temporal cortex, and insula area. And it was discovered that brain activity increase in temporal area and occipital area was more pronounced in the exposure group than in the control group. This result suggests that chronic exposure to Mn in the work environment affects brain activation neuro-network.

• Investigative Magnetic Resonance Imaging
• /
• v.4 no.1
• /
• pp.14-19
• /
• 2000

Purpose : This study was to present the functional brain mapping of both functional magnetic resonance imaging(MRI) and transcranial magnetic stimulation(TMS) in a case of schizencephaly. Materials and methods : A 28-year-old man, who had left hemiplegia and schizencephaly in right cerebral hemisphere, was exacted with both functional MRI and TMS. Motor function of left hand was decreased whereas right hand was within normal limit. For functional MRI, gradient-echo echo planar imaging($TR/TE/{\alpha}$=1.2 sec/90 msec/90) was employed. The paradigm of motor task consisted of repetitive self-paseo hand flexion-extension exercises with 1-2 Hz periods. An image set of 10 slices was repetitively acquired with 15 seconds alternating periods of task performance and rest and total 6 cycles (three ON periods and three OFF periods) were performed. In brain mapping, TMS was performed with the round magnetic stimulator (mean diameter; 90mm). The magnetic stimulation was done with 80% of maximal output. The latency and amplitude of motor evoked potential(MEP)s were obtained from both abductor pollicis brevis(APB) muscles. Results : Functional MRI revealed activation of the left primary motor cortex with flexion-extension exercises of healthy right hand. On the other hand, the left primary motor cortex, left supplementary motor cortex, and left promoter areas were activated with flexion-extension exercises of left hand. In TMS, magnetic evoked potentials were induced in no areas of right cerebral hemisphere, but in 5 areas of left corebral hemisphere from both abductor pollicis brevis. Latency, amplitude, and contour of response of the magnetic evoked potentials in both hands were similar. Conclusion : Functional MRI and TMS in a patient with schizencephaly were successfully used to localize cortical motor function. Ipsilateral motor pathway is thought to be secondary to reinforcement of the corticospinal tract of the ipsilateral motor cortex.

• Journal of Environmental Health Sciences
• /
• v.37 no.2
• /
• pp.102-112
• /
• 2011

Objectives: The purpose of this study is to analyze the effects of chronic exposure by welders to manganese (Mn) through an analysis of the degree of brain activity in different activities such as cognition and motor activities using the neuroimaging technique of functional magnetic resonance imaging (fMRI). The neurotoxic effect that Mn has on the brain was examined as well as changes in the neuro-network in motor areas, and the usefulness of fMRI was evaluated as a tool to determine changes in brain function from occupational exposure to Mn. Methods: A survey was carried out from July 2010 to October 2010 targeting by means of a questionnaire 160 workers from the shipbuilding and other manufacturing industries. Among them, 14 welders with more than ten years of job-related exposure to Mn were recruited on a voluntary basis as an exposure group, and 13 workers from other manufacturing industries with corresponding gender and age were recruited as a control group. A questionnaire survey, a blood test, and an fMRI test were carried out with the study group as target. Results: Of 27 fMRI targets, blood Mn concentration of the exposure group was significantly higher than that of the control group (p<0.001), and Pallidal Index (PI) of the welder group was also significantly higher than that of the control group (p<0.001). As a result of the survey, the score of the exposure group in self-awareness of abnormal nerve symptoms and abnormal musculoskeletal symptoms was higher than those of the control group, and there was a significant difference between the two groups (p<0.05, respectively). In the correlation between PI and the results of blood tests, the correlation coefficient with blood Mn concentration was 0.893, revealing a significant amount of correlation (p<0.001). As for brain activity area within the control group, the right and the left areas of the superior frontal cortex showed significant activity, and the right area of superior parietal cortex, the left area of occipital cortex and cerebellum showed significant activity. Unlike the control group, the exposure group showed significant activity selectively on the right area of premotor cortex, at the center of supplementary motor area, and on the left side of superior temporal cortex. In the comparison of brain activity areas between the two groups, the exposure group showed a significantly higher activation state than did the control group in such areas as the right and the left superior parietal cortex, superior temporal cortex, and cerebellum including superior frontal cortex and the right area of premotor cortex. However, in nowhere did the control group show a more activated area than did the exposure group. Conclusions: Chronic exposure to Mn increased brain activity during implementation of hand motor tasks. In an identical task, activation increased in the premotor cortex, superior temporal cortex, and supplementary motor area. It was also discovered that brain activity increase in the frontal area and occipital area was more pronounced in the exposure group than in the control group. This result suggests that chronic exposure to Mn in the work environment affects brain activation neuro-networks.

• Journal of Oriental Neuropsychiatry
• /
• v.24 no.4
• /
• pp.419-434
• /
• 2013

Objectives: The object of this study is to observe the cognition and motor function recovery effects of Joojakwhan (JJW), a traditional Korean poly-herbal formula for treating various neuropsychiatric diseases such as dementia, for the mildly stroke rats, with 60 minutes of reperfusion transient middle cerebral artery occlusion (tMCAO). Methods: In the present study, 125, 250 and 500 mg/kg of JJW were orally administered, once per day for 10 continuous days 2 hours after the tMCAO. The body weight changes, infarct sizes under 2% 2, 3, 5-triphenyl tetrazolium chloride (TTC) stain, sensorimotor functions and cognitive motor behavior tests were serially monitored with cerebral caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP)-immunoreactivities and histopathological changes. The effects of tMCAO on sensorimotor functions were evaluated by using of limb placing and body-swing tests, and the cognitive motor behaviors were also observed with water maze tests. Results: From the results of tMCAO, with marked decreases of body weights, disorders of sensorimotor functions increases the limb placing test scores, and decrease the numbers and percentages of body swings to the ipsilateral sides. The cognitive motor behaviors increases the distances and time to reach the escape platform which included the inhibitions of the decreases with repeated trials that were observed with focal cerebral cortex infarct volumes. In addition, the marked increases of the atrophy, numbers of degeneration, caspase-3- and PARP-immunoreactive cells around peri-infarct ipsilateral cerebral cortex were also observed in tMCAO controls when compared with the sham control rats, respectively. Conclusions: The results obtained from this study suggest that oral administrations of JJW indicate obvious cognitions and motor function recoveries of the rats with tMCAO, mild strokes, which are mediated by neuro-protective effects through known antioxidant effects of components.

• Journal of Life Science
• /
• v.23 no.2
• /
• pp.157-166
• /
• 2013

This study aimed to investigate whether nociceptin contributes to the alterations in cerebral blood flow (CBF) regulation following postnatal exposure to ethanol in Sprague-Dawley rats. Animals received ethanol twice a day, 2 hr apart, on postnatal 6, 7 and 8 days. The changes in regional CBF (rCBF) in response to the changes in mean arterial blood pressure were determined at 4-, 8-, and 12-week of age by laser-Doppler flowmetry. Hypotension was induced by the gradual withdrawal of blood from arterial catheter, and the reversal of blood pressure was produced by the reinfusion of blood. Expression of nociceptin-like immunoreactivity was determined in dura mater and cerebral cortex using immunohistochemistry. Postnatal exposure to ethanol almost abolished the autoregulation of rCBF in all age groups. Pretreatment with nociceptin but not with [$Nphe^1$]nociceptin(1-13)$NH_2$, a selective competitive nociceptin receptor antagonist, 5 min prior to ethanol administration preserved the autoregulation of rCBF in all age groups. Postnatal exposure to ethanol markedly increased the expressions of nociceptin-like immunoreactivity in the dura mater and cerebral cortex, both of which were significantly inhibited by pretreatment with 7-nitroindazole monosodium salt as well as aminoguanidine 5 min prior to ethanol administration in all age groups. The values of arterial blood gas analysis were not significantly different from the basal levels in all groups. These results suggest that nociceptin deeply contributes to the compensatory mechanisms for the nitric oxide-dependent alterations in CBF autoregulation following postnatal exposure to ethanol.

• Animal cells and systems
• /
• v.2 no.1
• /
• pp.71-80
• /
• 1998

Glutamate dehydrogenase (GDH) is one of the main enzymes involved in the formation and metabolism of the neurotransmitter glutamate. In the present study, we investigated the distribution of the GDH-immunoreactive cells in the rat brain using monoclonal antibodies against bovine brain GDH isoprotein. GDH-immunoreactive cell were distributed in the basal ganglia, thalamus and the nuclei belong to substantia innominata, and its connecting area, subthalamic nucleus, zona incerta, and substantia niqra. We could see GDH-immunoreactive cells in the hippocampus, septal nuclei associated with the limbic system, the anterior thalamic nuclei connecting between the hypothalamus and limbic system, and its associated structures, amygdaloid nuclear complex, the dorsal raphe and median raphe nuclei and the reticular formation of the midbrain. The GDH-immunoreactive cells were shown in the pyramidal neurons of the cerebral cortex, the Purkinie cells of the cerebella cortex, their associated structures, ventral thalamic nuclei and the reticular thalamic nuclei that seem to function as neural conduction in the thalamus.

• Sleep Medicine and Psychophysiology
• /
• v.1 no.2
• /
• pp.193-196
• /
• 1994

Primary depression with cognitive impairment, referred to as depressive pseudodementia, may be mistaken for a progressive degenerative dementia. Recognition of primary depression is clinically important because of its treatability. To differentiate depression from degenerative dementia, author used brain SPECT. By the result the regional cerebral blood flow(rCBF) in elderly depressed patient was decreased in the right frontal cortex. The pattern of rCBF was different from that of dementia which shows decreased rCBF in bifrontal cortex. By using brain SPECT in depressed elderly patient with cognitive impairment, the discrimination from dementia will be more effective and accurate.

• Investigative Magnetic Resonance Imaging
• /
• v.20 no.4
• /
• pp.250-253
• /
• 2016

Acute Japanese encephalitis (JE) is an endemic viral infectious disease in various parts of Far East and Southeast Asian countries including Korea. Bilateral thalami are the most common involving sites in JE. Other areas including the basal ganglia, substantia nigra, red nucleus, pons, cerebral cortex and cerebellum may be also involved. We report an extremely unusual brain diffusion-weighted MR imaging (DWI) findings in a 53-year-old man with serologically proven JE involving unilateral deep gray matter and temporal lobe, which shows multifocal high signal intensities in left thalamus, left substantia nigra, left caudate nucleus and left medial temporal cortex on T2-weighted image and DWI with iso-intensity on apparent diffusion coefficient (ADC) map.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.83.1-83.1
• /
• 2003

The heterotrimeric G protein subunits (G ) are region-specifically expressed in brain such as hypothalamus and pituitary gland in abundant, suggesting that is may be associated with “stress-axis”. This study was designed to examine the effect of stress on the region-specific expression of various G subunits in rat brain. The localization of mRNAs encoding seven of G and striking region-specific patterns of expression were observed in 12 different regions of both non-stressed and stressed rat brain; (1) frontal cortex area, (2) cerebral cortex area, (3) striatum, (4) hippocampus area, (5) thalamus, (6) brain stem, (7) cerebellum area, (8) hypothalamus, (9) septum, (10) amygdala, (11) preoptic area, and (12) pituitary gland. (omitted)

• Annals of Clinical Neurophysiology
• /
• v.13 no.1
• /
• pp.1-12
• /
• 2011

Transcranial magnetic stimulation (TMS) is a non-invasive tool used to study aspects of human brain physiology, including motor function and the pathophysiology of various brain disorders. A brief electric current passed through a magnetic coil produces a high-intensity magnetic field, which can excite or inhibit the cerebral cortex. Although various brain regions can be evaluated by TMS, most studies have focused on the motor cortex where motor evoked potentials (MEPs) are produced. Single-pulse and paired-pulse TMS can be used to measure the excitability of the motor cortex via various parameters, while repetitive TMS induces cortical plasticity via long-term potentiation or long-term depression-like mechanisms. Therefore, TMS is useful in the evaluation of physiological mechanisms of various neurological diseases, including movement disorders and epilepsy. In addition, it has diagnostic utility in spinal cord diseases, amyotrophic lateral sclerosis and demyelinating diseases. The therapeutic effects of repetitive TMS on stroke, Parkinson disease and focal hand dystonia are limited since the duration and clinical benefits seem to be temporary. New TMS techniques, which may improve clinical utility, are being developed to enhance clinical utilities in various neurological diseases.