• Applied Microscopy
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• 제48권4호
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• pp.102-109
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• 2018

Multiple synaptic boutons (MSBs) have been reported to be synapse with two or more postsynaptic terminals in one presynaptic terminal. These MSBs are known to be increased by various brain stimuli. In the motor cortex, increased number of MSB was observed in both acrobat training (AC) model and traumatic brain injury (TBI) model. Interestingly one is a physiological stimuli and the other is pathological insult. The purpose of this study is to compare the connectivity of MSBs between AC model and TBI model in the cerebral motor cortex, based on the hypothesis that the connectivity of MSBs might be different according to the models. The motor cortex was dissected from perfused brain of each experimental animal, the samples were prepared for routine transmission electron microscopy. The 60~70 serial sections were mounted on the one-hole grid and MSB was analyzed. The 3-dimensional analysis revealed that 94% of MSBs found in AC model synapse two postsynaptic spines from same dendrite. But, 28% MSBs from TBI models synapse two postsynaptic spines from different dendrite. This imply that the MSBs observed in motor cortex of AC model and TBI model might have different circuits for the processing the information.

• The Journal of Korean Physical Therapy
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• 제24권4호
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• pp.262-267
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• 2012

Purpose: This study was designed to analyze the differences in cerebral cortex activity of the elderly after extracting the movement related cortical potentials (MRCPs) from electroencephalogram (EEG) during a concentric and eccentric contraction of the elbow joint flexors, and entering them into the brain-mapping program to make the images. Methods: Right-dominant normal elderly people were divided into an eccentric contraction group and a concentric contraction group. Then, their MRCPs were measured using EEG and sEMG, during an eccentric and concentric contraction. Then, they were converted into images using the brain-mapping program. Results: Eccentric contraction group's $C_3$ and Cz showed statistically higher mean values of MRCP positive potential than the concentric contraction group. Conclusion: Researching a cerebral cortex activity, using MRCP, would provide basic data for clinical neuro-physiological researches on aging or neural plasticity of patients with a central nervous system injury.

• 동의생리병리학회지
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• 제33권6호
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• pp.356-362
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• 2019

Scutellaria baicalensis (SB) has widely used in the treatment for various brain diseases in the field of Oriental medicine. Biofermantation of SB can make major chemical constituents of SB to pass blood-brain barrier easily and to have more potent anti-oxidant ability. There is a little information about the contribution of fermented SB (FSB) to the formation or maintenance of the neural plasticity in the hippocampus. The purpose of this study was to evaluate effects of FSB extract on hydrogen peroxide (H₂O₂) - induced impairments of the induction and maintenance of long-term potentiation (LTP), an electrophysiological marker for the neural plasticity in the hippocampus. From hippocampal slices of rats, the field excitatory postsynaptic potentials (fEPSPs) were evoked by the electrical stimulation to the Schaffer collaterals - commissural fibers in the CA1 areas and LTP by theta-burst stimulation by using 64 - channels in vitro multi-extracellular recording system. In order to induce oxidative stress to hippocampal slices two different concentrations (200, 400 μM) of H₂O₂ were given to the perfused aCSF before and after the LTP induction, respectively. The ethanol extract of FBS with concentration of 25 ㎍/ml, 50 ㎍/ml was diluted in perfused aCSF that had 200 μM H₂O₂, respectively. Oxidative stress by the treatment of H₂O₂ resulted in decrease of the induction rate of LTP in the CA1 area with a dose - dependent manner. However, the ethanol extract of FSB prevented the reduction of the induction rate of LTP caused by H₂O₂ - induced oxidative stress with a dose - dependent manner. These results may support a potential application of FSB to ameliorate impairments of hippocampal dependent neural plasticity or memory caused by oxidative stress.

• 세라미스트
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• 제21권2호
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• pp.4-18
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• 2018

Lastly, neuromorphic computing chip has been extensively studied as the technology that directly mimics efficient calculation algorithm of human brain, enabling a next-generation intelligent hardware system with high speed and low power consumption. Three-terminal based synaptic transistor has relatively low integration density compared to the two-terminal type memristor, while its power consumption can be realized as being so low and its spike plasticity from synapse can be reliably implemented. Also, the strong electrical interaction between two or more synaptic spikes offers the advantage of more precise control of synaptic weights. In this review paper, the results of synaptic transistor mimicking synaptic behavior of the brain are classified according to the channel material, in order of silicon, organic semiconductor, oxide semiconductor, 1D CNT(carbon nanotube) and 2D van der Waals atomic layer present. At the same time, key technologies related to dielectrics and electrolytes introduced to express hysteresis and plasticity are discussed. In addition, we compared the essential electrical characteristics (EPSC, IPSC, PPF, STM, LTM, and STDP) required to implement synaptic transistors in common and the power consumption required for unit synapse operation. Generally, synaptic devices should be integrated with other peripheral circuits such as neurons. Demonstration of this neuromorphic system level needs the linearity of synapse resistance change, the symmetry between potentiation and depression, and multi-level resistance states. Finally, in order to be used as a practical neuromorphic applications, the long-term stability and reliability of the synapse device have to be essentially secured through the retention and the endurance cycling test related to the long-term memory characteristics.

• Journal of Ginseng Research
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• 제40권1호
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• pp.55-61
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• 2016

Background: A number of neurological and neurodegenerative diseases share impaired cognition as a common symptom. Therefore, the development of clinically applicable therapies to enhance cognition has yielded significant interest. Previously, we have shown that activation of lysophosphatidic acid receptors (LPARs) via gintonin application potentiates synaptic transmission by the blockade of $K^+$ channels in the mature hippocampus. However, whether gintonin may exert any beneficial impact directly on cognition at the neural circuitry level and the behavioral level has not been investigated. Methods: In the current study, we took advantage of gintonin, a novel LPAR agonist, to investigate the effect of gintonin-mediated LPAR activation on cognitive performances. Hippocampus-dependent fear memory test, synaptic plasticity in the hippocampal brain slices, and quantitative analysis on synaptic plasticity-related proteins were used. Results: Daily oral administration of gintonin for 1 wk significantly improved fear memory retention in the contextual fear-conditioning test in mice.We also found that oral administration of gintonin for 1 wk increased the expression of learning and memory-related proteins such as phosphorylated cyclic adenosine monophosphate-response element binding (CREB) protein and brain-derived neurotrophic factor (BDNF). In addition, prolonged gintonin administration enhanced long-term potentiation in the hippocampus. Conclusion: Our observations suggest that the systemic gintonin administration could successfully improve contextual memory formation at the molecular and synaptic levels as well as the behavioral level. Therefore, oral administration of gintonin may serve as an effective noninvasive, nonsurgical method of enhancing cognitive functions.

• Annals of Clinical Neurophysiology
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• 제14권2호
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• pp.64-71
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• 2012

Background: It is generally accepted that upper motor neuron (UMN) lesion can alter lower motor neuron (LMN) function by the plasticity of neural circuit. However there have been only few researches regarding the axonal excitability of LMN after UMN injury especially during the acute stage. The aim of this study was to investigate the nerve excitability properties of the LMNs following an acute to subacute supratentorial corticospinal tract lesion. Methods: An automated nerve excitability test (NET) using the threshold tracking technique was utilized to measure multiple excitability indices in median motor axons of 15 stroke patients and 20 controls. Testing of both paretic and non-paretic side was repeated twice, during the acute stage and subacute stage. The protocols calculated the strength-duration time constant from the duration-charge curve, parameters of threshold electrotonus (TE), the current-threshold relationship from sequential sub-threshold current, and the recovery cycle from sequential supra-threshold stimulation. Results: On the paretic side, compared with the control group, significant decline of superexcitablity and increase in the relative refractory period were observed during the subacute stage of stroke. Additionally, despite the absence of statistical significance, a mildly collapsing in ('fanning in') of the TE was found. Conclusions: Our results suggest that supratentorial brain lesions can affect peripheral axonal excitability even during the early stage. The NET pattern probably suggests background membrane depolarization of LMNs. These features could be associated with trans-synaptic regulation of UMNs to LMNs as one of the "neural plasticity" mechanisms in acute brain injury.

• The Journal of Korean Physical Therapy
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• 제13권2호
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• pp.281-292
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• 2001

This study was performed to investigate the effect of therapeutic exercise on brain-derived neurotrophic factor manifestation after global brain ischemia in rats. Nine rats with global ischemia were divided at random into two group. In the control group, three rats remained in cage. But, in the end, two rats were alive. In the therapeutic exercise group, six rats remained. The five rats of this group was swam for 30 minutes everyday for a week. The brain-derived neurotrophic factor expression was identified from immunohistochemistry. The results of this study were as follows : 1. In the control group, a little expression of brain-derived neurotrophic factor was observed at cortex and hippocampus layer, but cell body and axon was observed obscurely. 2. In the experimental group, a much expression of brain-derived neurotrophic factor was observed at cortex and hippocampus layer, and cell body and axon was observed clearly. In the neurological examination(beam-walking test). experimental group was obtained higher 1.4 points than control group. BDNF expression was increased by swimming for 30 minutes everyday for a week. Therefore, therapeutic exercise contribute to brain plasticity after brain ischemia.

• Journal of Korean Neurosurgical Society
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• 제46권1호
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• pp.1-4
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• 2009

Objective: To report an unsuspected adaptive plasticity of single upper motor neurons and of primary motor cortex found after microsurgical connection of the spinal cord with peripheral nerve via grafts in paraplegics and focussed discussion of the reviewed literature. Methods: The research aimed at making paraplegics walk again, after 20 years of experimental surgery in animals. Amongst other things, animal experiments demonstrated the alteration of the motor endplates receptors from cholinergic to glutamatergic induced by connection with upper motor neurons. The same paradigm was successfully performed in paraplegic humans. The nerve grafts were put into the ventral-lateral spinal tract randomly, with out possibility of choosing the axons coming from different areas of the motor cortex. Results: The patient became able to selectively activate the re-innervated muscles she wanted without concurrent activities of other muscles connected with the same cortical areas. Conclusion: Authors believe that unlike in nerve or tendon transfers, where the whole cortical area corresponding to the transfer changes its function a phenomenon that we call "brain plasticity by areas". in our paradigm due to the direct connection of upper motor neurons with different peripheral nerves and muscles via nerve grafts motor learning occurs based on adaptive neuronal plasticity so that simultaneous contractions of other muscles are prevented. We propose to call it adaptive functional "plasticity by single neurons". We speculate that this phenomenon is due to the simultaneous activation of neurons spread in different cortical areas for a given specific movement, whilst the other neurons of the same areas connected with peripheral nerves of different muscles are not activated at the same time. Why different neurons of the same area fire at different times according to different voluntary demands remains to be discovered. We are committed to solve this enigma hereafter.

• Journal of Acupuncture Research
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• 제21권3호
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• pp.61-81
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• 2004

Background and Objective : The aim of this study was to investigate the effects of acupuncture and electroacupuncture on the DCX, PSA-NCAM, and pCREB expression in the brain of spontaneously hypertensive rats(SHR). Materials and Methods : SHR were divided into five groups: control group, acupuncture group, 2Hz electroacupuncture(EA) group and 100Hz EA group. We evaluated the changes of the DCX, PSA-NCAM, and pCREB positive cells using immunohistochemical method. In the olfactory bulb, we investigate the optical densities of the immunoactive cells. In the dentate gyrus and the piriform cortex, we count the immunoactive cells under the $100{\times}$ visual field optical microscope. Results : 1. The optical densities of DCX-positive cells in the subependymal zone were significantly decreased in all groups, compared to the control group. 2. The counts of DCX-positive cells in the dentate gyrus were significantly increased in all groups, compared to the control group. The counts of DCX-positive cells in the piriform cortex were significantly increased in the acupuncture and 100Hz EA group, compared to the control group. 3. The optical densities of PSA-NCAM-positive cells in the subependymal zone were significantly decreased in the acupuncture and 2Hz EA group, compared to the control group. 4. The counts of PSA-NCAM-positive cells in the dentate gyrus and the piriform cortex were significantly increased in all group, compared to the control group. 5. The counts of pCREB-positive cells in the dentate gyrus were significantly increased in all groups, compared to the control group. The counts of pCREB-positive cells in the piriform cortex were significantly increased in the acupuncture and 100Hz EA group, compared to the control group. Conclusion : We conclude that acupuncture and EA may affect neuronal cell proliferation, differentiation and plasticity in the brain.

• 동의생리병리학회지
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• 제26권6호
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• pp.894-901
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• 2012

The effect of Sopung-tang(SPT) and trans-cranial direct current stimulation(tDCS) was investigated in photothrombotic brain infarction(PTI) rats. Sprague-Dawley 80 rats, were divided into four groups. group I was experiental control group(n=20), group II was PTI induced and oral administration of SPT(n=20), group III was PTI induced and tDCS administration(n=20) and group IV was PTI induced and SPT and tDCS administration for 28 days on stroke rats(n=20). Analysis the neurological function test, 25 point behavior functional score test, and immunohistochemistric finding of GDNF expression, and electron microscopy assessment In motor behavior test, the outcome of group IV was significantly difference than the other group, and In immunohistochemistric finding, group II, III, IV were increase GDNF expression on 28 days, In electron microscopy finding, the all groups were degenerated of cell organelles, and synaptic plasticity were improvement of group II, III, IV(especially group IV) These results suggest that, 28days application of SPT and tDCS was the motor function and histopathologic, micro-morphological improvement of motor function recovery and positive influence on synaptic plasticity.