• Title/Summary/Keyword: Somatosensory cortex

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Review of Somato Sensory Evoke Potential Test (체성감각유발전위검사에 대한 고찰)

  • Kim Myung-Chul;Kim Jin-Sang
    • The Journal of Korean Physical Therapy
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    • v.14 no.4
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    • pp.64-74
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    • 2002
  • The SSEP(SomatoSensory Evoke Potentials) test is a valid and repeatable technique which correlates with clinically assessed joint position & vibration sense, skin touch & pressure sense. Also SSEP study is a simple and quantitative test, and has been used to evaluate the sensoty system along the somatosensory pathway from peripheral sensory receptor to the cortex. The ascending pathway of SSEP has been know to be posterior column-lemniscal pathway, but not without controversy. There are two kind of test mathods : one of test is median nerve SSEP and other test is posterior tibial nerve SSEP. Recently, SSEP used to performed to evaluate the usefulness of dermatomal SSEP(D-SSEP) and segmental SSEP(5-SSEP) for the diagnosis of lumbasacral radiculopathy, and it can be measure of ingual ahd palatine evoked potentials & indicator of medullary function useful for the diagnosis of brain death.

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Importance of Differential Diagnosis of a Possible Brain Tumor in Patients with Cervical Radiculopathy

  • So, Jin-Shup;Kim, Young-Jin;Lee, Sang-Koo;Cho, Chun-Sung
    • Journal of Korean Neurosurgical Society
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    • v.65 no.1
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    • pp.145-150
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    • 2022
  • Lesions occurring simultaneously in the somatosensory or motor cortex of the brain and the cervical spine are rare. Brain tumors can cause similar symptoms to cervical lesions which can lead to confusion in treatment priorities. Moreover, if cervical disease is noticeably observed in radiologic findings of a patient complaining of cervical radiculopathy with non-specific electromyography results, it is common to no longer perform further evaluation. Here we introduce two cases where the cause of cervical radiculopathy was first considered to be the result of a degenerative cervical disease but was later discovered to be a result of a brain tumor.

Evoked Potentials before the Intractable Epilepsy Surgery (난치성 뇌전증 환자에서 수술 전 유발전위검사)

  • Lim, Sung Hyuk;Park, Sang Ku;Baek, Jae Seung;Kim, Kab Kyu;Kim, Ki Eob;Lee, Yu Ji
    • Korean Journal of Clinical Laboratory Science
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    • v.51 no.2
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    • pp.198-204
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    • 2019
  • Various treatments can be attempted in patients with intractable epilepsy, in whom the symptoms of seizures are not controlled by various drugs. On the other hand, in patients requiring a surgical method, a preoperative examination is needed to determine the portion of seizure site to be resected. Electrodes are inserted into the cerebral cortex for accurate lesion measurements and safe operation. The electrodes inserted in the cortex not only record the electroencephalography (EEG), but also allow various tests to confirm the function of the part. One of these methods is the evoked potential test. From January 2015 to December 2018, the trends of measured waveforms in were analyzed 70 patients. The somatosensory evoked potential (SSEP) recorded on the electrode inserted in the cerebral cortex can be searched for the pathway of the central sulcus to avoid the primary motor area and primary sensory area. In addition, using the middle latency auditory evoked potentials (MLAEP) and flash visual evoked potentials (FVEP), the functional cortex in the auditory cortex and the visual cortex were compared with the seizure focus point on the EEG to help determine the location of the ablation and minimize functional impairment after surgery.

Characteristics of Trigeminal Evoked Potential and It's Pathway in the Rat (백서에서 삼차신경 유발전위의 특성과 경로 분석)

  • Kim, Se-Hyuk;Zhao, Chun-Zhi;Kwon, Oh-Kyoo;Lee, Bae-Hwan;Park, Yong-Gou;Chung, Sang-Sup
    • Journal of Korean Neurosurgical Society
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    • v.29 no.8
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    • pp.985-994
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    • 2000
  • Objective : There are some advantages of trigeminal evoked potential(TEP) recording compared to other somatosensory evoked potential(SSEP) recordings. The trigeminal sensory pathway has a pure sensory nerve branch, a broader receptive field in cerebral cortex, and a shorter pathway. Despite these advantages, there is little agreement as to what constitutes a normal response and what wave forms truly characterize the intraoperative TEP. This study presents the normative data of TEP recorded on the epidural surface of the rat with a platinum ball electrode. Materials & Methods : Under general anesthesia with urethane, the adult Sprague-Dawley male rats(300-350g) were given electrical stimulation with two stainless steel electrodes which were inserted into the subcutaneous layer of the area around whiskers. A reference electrode was positioned in the temporalis muscle ipsilateral to the recording site. Results : TEPs were recorded in the Par I area of somatosensory cortex and recorded most apparently on the point of 2mm posterior from the bregma and 6mm lateral from the midline. The typical wave form consisted of 5 peaks (N1-P1-N2-P2-N3 according to emerging order, upward negativity). Each latency to corresponding peaks was not influenced by the different intensities of stimulation, especially from 1 to 5mA. Average latencies of 5 peaks were in the following order ; 7.7, 11.1, 15, 22.3, 29.4ms. There was also no significant difference between latencies before and after administration of muscle relaxant(pancuronium). For the electrophysiological localization of recorded waves, the action potential of a single unit was recorded with glass microelectrode(filled with 2M NaCl, $3-5M{\Omega}$) in the thalamus of rat. A sharp wave was recorded in the VPM nucleus, in which the latency was shorter than that of N1. This suggests that all 5 peaks were generated by neural activities in the suprathalamic pathway. Conclusion : In terms of recording near-field potentials, our data also suggests that TEP in the rat may be superior to other SSEPs. In overall, these results may afford normative data for the studies of supratentorial lesions such as hydrocephalus or cerebral ischemia which can have an influence on near-field potentials.

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Somatosensory Afferent Pathway Tracing from Rat Anterior Cruciate Ligament Nerve Endings to Cerebral Cortex Using Pseudorabies Virus (쥐 전방십자인대 신경말단에서 대뇌피질까지 Pseudorabies virus(PRV)를 이용한 구심성 체성감각신경로의 추적)

  • Kim, Jin-Su;Jeong, Soon-Taek;Cho, Se-Hyun;Park, Hyung-Bin
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.4 no.1
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    • pp.29-35
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    • 2005
  • Purpose: The anterior cruciate ligament(ACL) has a neuromuscular control function as evidenced by the presence within it of mechanoreceptor. Although these mechanoreceptors have been identified, the afferent somatosensory pathways from ACL to the cerebrum have yet to be demonstrated in their entirety. In order to trace these afferent pathway, we conducted a viral trans-synaptic tracing experiment using the neurotropic pseudorabies virus(PRV). Material and Methods: The PRV was injected into the ACL of rats and allowed to replicate and spread trans-synaptically for 6 to 7 days. The brain and spinal cord of each sacrificed rat was then removed and processed immunohistochemically to detect the presence of PRV. Results: PRV-immunoreactive neurons were found to be localized in several different regions from the spinal cord to the cerebrum. Four nuclei in the reticular formation of the brain stem demonstrated strong positive labeling: the mesencephalic reticular nucleus, magnocelluar reticular nucleus, paragigantocellular reticular nucleus, and gigantocellular reticular nucleus. Conclusions: This findings suggests that the nerve endings of the rat ACL project into the cerebrum and that the reticular formation may play an important role in the afferent pathway of those nerve endings.

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CHANGES OF SENSORY AND SOMATOSENSORY EVOKED POTENTIALS FOLLOWING A NEEDLE INJURY ON THE INFERIOR ALVEOLAR NERVE IN RATS (백서 하치조 신경 손상에 따른 감각 유발전위와 체성감각 유발전위의 변화에 관한 연구)

  • Woo, Seung-Chel;Kim, Soo-Nam;Lee, Dong-Keun;Cheun, Sang-Woo
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.18 no.4
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    • pp.652-672
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    • 1996
  • Dysfunction of the inferior alveolar nerve may result from trauma, diseases or iatrogenic injury. The development and refinement of an objective method to evaluate this clinical problem is highly desirable and needed, especially concerning for an increasing medico-legal issue. Evoked potential techniques have attracted considerable attention as a means of assessing the function and integrity of nerve pathways. The purpose of this study was to characterize the Sensory Evoked Potentials(SEPs) and Somatosensory Evoked Potentials(SSEPs) elicited by electrical stimulation of mental nerve. SEPs and SSEPs were measured and analyzed statistically before and after needle injury on the inferior alveolar nerve of Sprague-Dawalye rats. Measuring SEPs was more sensitive in evaluation of the recovery of sensory function from inferior alveolar nerve injury then measuring SSEPs but we measured SSEPs in the hope of providing a safe, simple and objective test to check oral and facial sensibility, which is acceptable to the patient. We stimulated mental nerve after needle injury on the inferior alveolar nerve and SEPS on the level of mandibular foramen and SSEPs on the level of cerebral cortex were recorded. Threshold, amplitude, and latency of both of SEPs and SSEPs were analyzed. The results were as follows ; 1. Threshold of SEPs and SSEPs were $184{\pm}14{\mu}A$ and $164{\pm}14{\mu}A$ respectively. 2 SEPs were composed of 2 waves, i.e., N1 N2 in which N1 was conducted by II fibers and N2 was conducted by III fibers. 3. SSEPS were composed of 5 waves, of which N1 and N2 shower statistically significant changes(p<0.01, unpaired t-test). 4. SEPs and SSEPs were observed to be abolished immediately after local anesthesia and recovered 30 minutes later. 5. SEPs were abolished immediately after injury. N1 of SSEPs was abolished immediately and amplitued of N2 was decreased($20.7{\pm}12.2%$) immediately after 23G needle injury, but N3, N4 and N5 did not change significantly. Recovery of waveform delayed 30 minutes in SEPs and 45 minutes in SSEPs. 6. The degree of decrease in amplitude of SEPs and SSEPs, after 30G needle injury was smaller than those with 23G. SEPs recorded on the level of mandibular foramen were though to be reliable and useful in the assessment of the function of the inferior alveolar nerve after injury. Amplitude of SSEPs reflected the function and integrity of nerve and measuring them provided a safe, simple and abjective test to check oral and facial sensibility. These results suggest that measuring SEPs and SSEPs are meaningful methods for objective assessment in the diagnosis of nerve injury. N1 and N2 of SSEPs can be useful parameters for the evaluation of the nerve function following a needle injury.

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Plasticity Associated Changes in Neurophysiological Tests Following Non Invasive Brain Stimulation in Stroke Rat Model (뇌졸중 쥐모델에서 비침습적뇌자극치료 이후 신경생리학적 검사에서 나타난 뇌가소성과 연관된 변화)

  • Sohn, Min Kyun;Song, Hee-Jung;Jee, Sungju
    • Annals of Clinical Neurophysiology
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    • v.16 no.2
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    • pp.62-69
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    • 2014
  • Background: Neuromodulation therapy has been used to an adjunctive treatment promoting motor recovery in stroke patients. The objective of the study was to determine the effect of repetitive transcranial magnetic stimulation (rTMS) on neurobehavioral recovery and evoked potentials in rats with middle cerebral artery occlusion. Methods: Seventy Sprague-Daley rats were induced permanent middle cerebral artery occlusion (MCAO) stroke model and successful stroke rats (n=56) assigned to the rTMS (n=28) and sham (n=28) group. The 10 Hz, high frequency rTMS gave on ipsilesional forepaw motor cortex during 2 weeks in rTMS group. The somatosensory evoked potential (SSEP) and motor evoked potential (MEP) were used to evaluate the electrophysiological changes. Behavioral function of the stroke rat was evaluated by the Rota rod and Garcia test. Results: Forty rats ($N_{rTMS}=20;\;N_{sham}=20$) completed all experimental course. The rTMS group showed better performance than sham group in Rota rod test and Garcia test at day 11 (p<0.05) but not day 18 (p>0.05). The amplitude of MEP and SSEP in rTMS group was larger than sham group at day 18 (p<0.05). Conclusions: These data confirm that the high frequency rTMS on ipsilesional cerebral motor cortex can help the early recovery of motor performance in permanent middle cerebral artery stroke model and it may simultaneously associate with changes in neurophysiological activity in brain.

Caffeic acid phenethyl ester protects against photothrombotic cortical ischemic injury in mice

  • Hwang, Sun Ae;Kim, Chi Dae;Lee, Won Suk
    • The Korean Journal of Physiology and Pharmacology
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    • v.22 no.1
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    • pp.101-110
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    • 2018
  • In this study, we aimed to investigate the neuroprotective effects of caffeic acid phenethyl ester (CAPE), an active component of propolis purified from honeybee hives, on photothrombotic cortical ischemic injury in mice. Permanent focal ischemia was achieved in the medial frontal and somatosensory cortices of anesthetized male C57BL/6 mice by irradiation of the skull with cold light laser in combination with systemic administration of rose bengal. The animals were treated with CAPE (0.5-5 mg/kg, i.p.) twice 1 and 6 h after ischemic insult. CAPE significantly reduced the infarct size as well as the expression of tumor necrosis $factor-{\alpha}$, hypoxiainducible $factor-1{\alpha}$ monocyte chemoattractant protein-1, $interleukin-1{\alpha}$, and indoleamine 2,3-dioxygenase in the cerebral cortex ipsilateral to the photothrombosis. Moreover, it induced an increase in heme oxygenase-1 immunoreactivity and interleukin-10 expression. These results suggest that CAPE exerts a remarkable neuroprotective effect on ischemic brain injury via its anti-inflammatory properties, thereby providing a benefit to the therapy of cerebral infarction.

Matrix Metalloproteinase Inhibitors Attenuate Neuroinflammation Following Focal Cerebral Ischemia in Mice

  • Park, Cheol-Hong;Shin, Tae-Kyeong;Lee, Ho-Youn;Kim, So-Jung;Lee, Won-Suk
    • The Korean Journal of Physiology and Pharmacology
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    • v.15 no.2
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    • pp.115-122
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    • 2011
  • The aim of this study was to investigate whether matrix metalloproteinase (MMP) inhibitors attenuate neuroinflammation in an ischemic brain following photothrombotic cortical ischemia in mice. Male C57BL/6 mice were anesthetized, and Rose Bengal was systemically administered. Permanent focal ischemia was induced in the medial frontal and somatosensory cortices by irradiating the skull with cold white light. MMP inhibitors, such as doxycycline, minocycline, and batimastat, significantly reduced the cerebral infarct size, and the expressions of monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), and indoleamine 2,3-dioxygenase (IDO). However, they had no effect on the expressions of heme oxygenase-1 and neuroglobin in the ischemic cortex. These results suggest that MMP inhibitors attenuate ischemic brain injury by decreasing the expression levels of MCP-1, TNF-${\alpha}$, and IDO, thereby providing a therapeutic benefit against cerebral ischemia.