• The Journal of Korean Physical Therapy
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• v.22 no.2
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• pp.25-30
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• 2010

Purpose: Behavior and movement are accomplished by voluntary contractions of skeletal muscles. There are three types of muscle contractions: concentric, isometric and eccentric. The aim of our study was to determine whether there is a difference in the cortical activation pattern between concentric contraction and eccentric contraction of the wrist extensor muscle. Methods: Four healthy right-handed volunteers without any previous history of physical or neurological illness were recruited. fMRI scanning was done during 4 repeated blocks of concentric and eccentric exercise of the wrist joint. Subjects exercised for 12 seconds and then rested for 12 seconds before beginning the second set of exercises. To determine the excitability of cortical neurons during exercise, voxel count and intensity index were analyzed. Results: For right hand movements, when concentric contractions of the right wrist were done, only the left primary motor area was activated. In contrast, during eccentric contraction, both the primary motor area and secondary motor area were activated. For left hand movements, both concentric and eccentric contractions induced only the supplementary motor cortex and the contralateral primary motor cortex. Conclusion: During eccentric contractions, both the primary motor area and secondary motor area are activated in ipsilateral and contralateral brain areas. Thus, eccentric contractions require more complex and difficult movements than concentric contractions do.

• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.52-57
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• 2000

Purpose : The purpose of this study was to investigate the pattern of cerebral response to motor tasks in patients with schizophrenia compared with normal subjects using functional MRI. Materials and methods ; Nine right handed-schizophrenic patients and six right-handed normal subjects were included. We used right hand movement as task. Series of 120 consecutive echo-planar images per section were acquired during three cycles of task and rest activations. Lateralization index of cortical response was measured and compared between patients and normal subjects. Results ; Right hand motor task was associated with greater activation in left sensorimotor cortex than the right in normal subjects. Schizophrenia patients showed relatively decreased activation in left cortex and increased activation in right cortex compared with normal subjects. In one patient, reversed lateralization was noted. Conclusion : Normal hemispheric asymmetry of cortical response to motor task was found in different pattern in schizophrenia. Our result is consistent with functional disturbance of motor circuitry in this disorder. Functional MRI will play an important role in diagnosis and research of this disorder.

• Korean Institute of Interior Design Journal
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• v.25 no.2
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• pp.30-40
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• 2016

This study analyzed the attention concentration tendencies of one(1) subject who showed convergent exploratory acts actively through the gaze-brainwave measurement experiment of cafe space images and our research findings are as follows. First, the areas of interest (AOIs) that the subject gazed visually by paying attention to it and concentrating on it at a cafe space include counter&menu area, sign area, partition area, image wall area, stairs area, and movable furniture area, and built-in furniture area: seven areas in total. Second, conscious gaze frequency appeared the highest in counter&menu area, and conscious gaze appeared more later than in initial times. Third, conscious gaze pattern was divided into the zone that explored various areas dispersely (distributed exploratory zone) and the zone that explored between particular areas concentratedly (intensive exploratory zone). Fourth, as a result of analyzing the brainwave attention concentration, it was found that the attention concentration in prefrontal lobe (Fp1, Fp2) and frontal lobe (F3, F4) rose to a higher level in the zone of 15 to 16 seconds and this time zone was considered to be a zone where gazing at counter&menu area was very active. In addition, the attention concentration appeared higher in the initial zone than in the later zone, among the entire experimental time zones. Finally, as a result of analyzing the changes in activation by brain portion of the SMR wave expressed when maintaining the arousal and attention concentration, it was found that the right prefrontal lobe and the frontal lobe became activated in the time zone when the intensive exploration of "counter&menu area" and "movable furniture${\leftrightarrow}$built-in furniture area" had occurred and the time zone when the intensive exploration of "image wall${\leftrightarrow}$partition area" and "counter&menu${\leftrightarrow}$sign area" had occurred.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.4
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• pp.349-362
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• 2020

Temperature affects the firing pattern and electrical activity of neurons in animals, eliciting diverse responses depending on neuronal cell type. However, the mechanisms underlying such diverse responses are not well understood. In the present study, we performed in vitro recording of abdominal ganglia cells of Aplysia juliana, and analyzed their burst firing patterns. We identified atypical bursting patterns dependent on temperature that were totally different from classical bursting patterns observed in R15 neurons of A. juliana. We classified these abnormal bursting patterns into type 1 and type 2; type 1 abnormal single bursts are composed of two kinds of spikes with a long interspike interval (ISI) followed by short ISI regular firing, while type 2 abnormal single bursts are composed of complex multiplets. To investigate the mechanism underlying the temperature dependence of abnormal bursting, we employed simulations using a modified Plant model and determined that the temperature dependence of type 2 abnormal bursting is related to temperature-dependent scaling factors and activation or inactivation of potassium or sodium channels.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.179-185
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• 2013

In this paper, the RTA-ERP(Response Time Aligned-Evoked Relative Potential) was modelled to analyze the effect of motor activation pattern in response to visual sensory stimuli. Simon effect was analysed using the amplitude response of RTA-ERP and measured response time. The 'odd number' experiments, which identify an odd number mixed with same numbers, was performed with 15 healthy adult participants(9 males and 6 females, whose mean age of 31) for 7 minutes for each participant. Throughout experimentation, we observed that the proposed RTA-ERP can compensate the timing variation due to different neural processing procedures in the brain, and shows enhanced LRP(Lateralized Readiness Potential) and Pe(Error Related Positivity). Regarding to 'congruence' and 'incongruence' testing patterns, the amplitude of RTA-ERP and the response time for the 'congruence' are $0.03{\mu}V$ larger, and 43 ms faster than those for the 'incongruence', respectively. The amplitude characteristics of RTA-ERP, obtained by synchronizing the onset times with respect to response time, corresponds more likely to that of P300 in the ERP pattern (the characteristics of the Simon effect).

• The Korean Journal of Pain
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• v.13 no.2
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• pp.143-148
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• 2000

Background: Trigeminovascular system is implicated in the pathophysiology of the headache in migraine. This study was designed to evaluate the pattern of Fos protein expression in trigeminal nociceptive central pathway after meningeal stimulation of rats by capsaicin. Methods: The expression of Fos protein was examined by immunohistochemistry in thalamus, brainstem and upper cervical cord (at three levels corresponding to obex, 0.8 mm and 2 mm below obex) 2 hours after intracisternal injection of either diluted capsaicin solution (0.1 ml, $61{\mu}g/ml$) or normal saline (0.1 ml) through a catheter placed in the cisterna magna, or following epidural instillation of diluted capsaicin solution in urethane-anesthetized Sprague-Dawley rats. Results: Fos immunoreactivity was strongly expressed within lamina I, II of bilateral trigeminal nucleus caudalis (TNC) after cisternal capsaicin injection and magnitude of expression was greatest at level 2.0 mm below obex. Epidural capsaicin caused much less labelling than cisternal capsaicin. Fos positive cells were also observed in area postrema, nucleus of the solitary tract, medullary reticular nucleus and midline nuclear groups of the thalamus with similar intensity between capsaicin and control group. Conclusions: These results indicate that the injection of capsaicin into the cisterna magna is an effective stimulus for the induction of Fos protein within TNC through activation of trigeminovascular afferents and this animal model can be useful for the evaluation of the pathophysiology and drug development in migraine and related headache.

• Development and Reproduction
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• v.14 no.1
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• pp.35-41
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• 2010

Mammalian reproduction is regulated by a feedback circuit of the key reproductive hormones such as GnRH, gonadotropin and sex steroids on the hypothalamic-pituitary-gonadal axis. In particular, the onset of female puberty is triggered by gain of a pulsatile pattern and increment of GnRH secretion from hypothalamus. Previous studies including our own clearly demonstrated that genistein (GS), a phytoestrogenic isoflavone, altered the timing of puberty onset in female rats. However, the brain-specific actions of GS in female rats has not been explored yet. The present study was performed to examine the changes in the activities of GnRH neurons and their neural circuits by GS in female rats. Concerning the drug delivery route, intracerebroventricular (ICV) injection technique was employed to eliminate the unwanted actions on the extrabrain tissues which can be occurred if the testing drug is systemically administered. Adult female rats (PND 100, 210-230 g BW) were anaesthetized, treated with single dose of GS ($3.4{\mu}g$/animal), and sacrificed at 3 hrs post-injection. To determine the transcriptional changes of reproductive hormone-related genes in hypothalamus, total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). ICV infusion of GS significantly raised the transcriptional activities of enhanced at puberty1 (EAP-1, p<0.05), glutamic acid decarboxylase (GAD67, p<0.01) which are known to modulate GnRH secretion in the hypothalamus. However, GS infusion could not change the mRNA level of nitric oxide synthase 2 (NOS-2). GS administration significantly increased the mRNA levels of KiSS-1 (p<0.001), GPR54 (p<0.001), and GnRH (p<0.01) in the hypothalami, but decreased the mRNA levels of LH-$\beta$ (p<0.01) and FSH-$\beta$ (p<0.05) in the pituitaries. Taken together, the present study indicated that the acute exposure to GS could directly activate the hypothalamic GnRH modulating system, suggesting the GS's disrupting effects such as the early onset of puberty in immature female rats might be derived from premature activation of key reproduction related genes in hypothalamus-pituitary neuroendocrine circuit.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.6
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• pp.371-382
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• 2011

We performed experiments using Aplysia neurons to identify the mechanism underlying the changes in the firing patterns in response to temperature changes. When the temperature was gradually increased from $11^{\circ}C$ to $31^{\circ}C$ the firing patterns changed sequentially from the silent state to beating, doublets, beating-chaos, bursting-chaos, square-wave bursting, and bursting-oscillation patterns. When the temperature was decreased over the same temperature range, these sequential changes in the firing patterns reappeared in reverse order. To simulate this entire range of spiking patterns we modified nonlinear differential equations that Chay and Lee made using temperature-dependent scaling factors. To refine the equations, we also analyzed the spike pattern changes in the presence of potassium channel blockers. Based on the solutions of these equations and potassium channel blocker experiments, we found that, as temperature increases, the maximum value of the potassium channel relaxation time constant, ${\tau}_n(t)$ increases, but the maximum value of the probabilities of openings for activation of the potassium channels, n(t) decreases. Accordingly, the voltage-dependent potassium current is likely to play a leading role in the temperature-dependent changes in the firing patterns in Aplysia neurons.

• Progress in Medical Physics
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• v.16 no.1
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• pp.1-9
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• 2005

The effect of the developed symmetric upper extremity motion trainer on the cortical activation pattern was investigated in three chronic hemiparetic patients using both fMRI and Fugl-Meyer test. The training program was performed at 1 hr/day, 5 days/week during 6 weeks. Fugl-Meyer tests were performed every two weeks during the training. fMRI was performed at 3T scanner with wrist flexion-extension in two different tasks before and after the training program: the only unaffected hand movement (Task 1) and passive movements of affected hand by the active movement of unaffected hand (Task 2). fMRI studies in Task 1 showed that cortical activations decreased in ipsilateral SMC but increased in contralateral SMC. Task 2 showed cortical reorganizations in bilateral SMC, PMA and SMA. Therefore, it seems that the cortical reorganization in chronic hemiparetic patients can be induced by the training with the developed symmetric upper extremity motion trainer.

• Journal of Life Science
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• v.25 no.6
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• pp.703-708
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• 2015

Hox genes encode a highly conserved family of homeodomain-containing transcription factors controlling vertebrate pattern formation along the anteroposterior body axis during embryogenesis. Retinoic acid (RA) is a key morphogen in embryogenesis and a critical regulator of both adult and embryonic cellular activity. Specifically, RA regulates Hox gene expression in mouse- or human-derived embryonic carcinoma (EC) cells. Histone modification has been reported to play a pivotal role in the process of RA-induced gene expression and cell differentiation. As histone modification is thought to play an essential role in RA-induced Hox gene expression, we examined RA-induced initiation of collinear expression of Hox genes and the corresponding histone modifications in F9 murine embryonic teratocarcinoma (EC) cells. Hox expression patterns and histone modifications were analyzed by semiquantitative RT-PCR, RNA-sequencing, and chromatin immuno-precipitation (ChIP)-PCR analyses. The Hoxc4 gene (D0) was initiated earlier than the Hoxc5 to –c10 genes (D3) upon RA treatment (day 0 [D0], day 1 [D1], and day 3 [D3]). The Hox nonexpressing D0 sample had a strong repressive marker, H3K27me3, than the D1 and D3 samples. In the D1 and D3 samples, reduced enrichment of the H3K27me3 marker was observed in the whole cluster. The active H3K4me3 marker was closely associated with the collinear expression of Hoxc genes. Thus, the Hoxc4 gene (D1) and all Hoxc genes (D3) expressed H3K4me3 upon transcription activation. In conclusion, these data indicated that removing H3K27me3 and acquiring H3K4me3 regulated RA-induced Hoxc gene collinearity in F9 cells.