We observed the steady-state visually evoked potential(SSVEP) from a healthy subject using a compact quad-channel potassium spin exchange relaxation-free(SERF) optically pumped magnetometer(OPM). To this end, 30 s of ...We observed the steady-state visually evoked potential(SSVEP) from a healthy subject using a compact quad-channel potassium spin exchange relaxation-free(SERF) optically pumped magnetometer(OPM). To this end, 30 s of data were collected, and SSVEP-related magnetic responses with signal intensity ranging from 150 fT to 300 f T were observed for all four channels. The corresponding signal to noise ratio(SNR) was in the range of 3.5–5.5. We then used different channels to operate the sensor as a gradiometer. In the specific case of detecting SSVEP, we noticed that the short channel separation distance led to a strongly diminished gradiometer signal. Although not optimal for the case of SSVEP detection, this set-up can prove to be highly useful for other magnetoencephalography(MEG) paradigms that require good noise cancellation.Considering its compactness, low cost, and good performance, the K-SERF sensor has great potential for biomagnetic field measurements and brain-computer interfaces(BCI).展开更多
Objective:To evaluate the changes of brainstem auditory evoked potential (BAEP) in patients with delayed encephalopathy after acute carbon monoxide poisoning. Methods: BAEPs were performed in 32 controls and 40 patien...Objective:To evaluate the changes of brainstem auditory evoked potential (BAEP) in patients with delayed encephalopathy after acute carbon monoxide poisoning. Methods: BAEPs were performed in 32 controls and 40 patients. Wave Ⅰ , Ⅱ , Ⅲ ,Ⅳ, Ⅴ latencies and Ⅰ-Ⅲ , Ⅲ-Ⅴ , Ⅰ-Ⅴ interpeak latencies were measured, respectively. Results: Abnormalities of BAEPs in 13 patients (13/40, 32 ％). Among the13 abnormal BAEPs, 3 displayed prolongation of latency to waves in one side, no potential in another side; 5 displayed a similar abnormality which was bilateral prolongation of latency to waves ;and another 5 displayed unilateral latency delay. Compared wave Ⅰ , Ⅱ , Ⅲ , Ⅳ, Ⅴ latencies and Ⅰ-Ⅲ , Ⅲ-Ⅴ , Ⅰ-Ⅴ interpeak latencies in the patients and the controls, there were no significant differences (P＞0.05). Conclusion: BAEPs can be used for evaluating the diagnostic and prognostic values in the cases of delayed encephalopathy after acute carbon monoxide poisoning.展开更多
Somatosensory and corticomotor evoked potentials (SSEP, CMEP) of the rats with acutely injured spinal cord were determined on the 7th, 15th, 30th, 60th, 120th and 240th day after they received implantation of the embr...Somatosensory and corticomotor evoked potentials (SSEP, CMEP) of the rats with acutely injured spinal cord were determined on the 7th, 15th, 30th, 60th, 120th and 240th day after they received implantation of the embryonic spinal cord from 14-day rat embryo into the injured cord. The motor functions of the hindlimbs were also observed. The rats with acute spinal cord injury and those with cord injury treated with the implantation of a piece of skeletal muscle served as the controls. It was found that the motor functions were recovered on the 30th day after implantation but the latent period of both SSEP and CMEP returned to mormal on the 240th day. At that time,the latent period of SSEP and CMEP of the 2 control groups also recovered gradually. It is believed that embryonic spinal cord implantation can affect the recovery of the motor functions of the rats. But more sophisticated methods are needed to clarify the interrelationship of the host cord with the grafts.展开更多
Somatasensory evoked potentials (SEP), sciatic nerve conduction velocity (CV), sciatic nerve Na+-K+-ATPase activity, and lipid peroxide content (LPO) were determined in 8 rats with chronic renal failure induced with 5...Somatasensory evoked potentials (SEP), sciatic nerve conduction velocity (CV), sciatic nerve Na+-K+-ATPase activity, and lipid peroxide content (LPO) were determined in 8 rats with chronic renal failure induced with 5/6 nephrectomy. Meanwhile, the histological changes were also oserved. Ten rats wtih sham operation served as the control. It was found that in the group with chronic renal failure, the mean peak latency of SEP was significantly prolonged and CV slower than those of the control. In the sciatic nerve tissue, Na+-K+-ATPase activity was loyer and LPO content higher in the tested group than in the control. No significant histological changes of the sciatic nerve were found under optical microscope. These findings suggest that the decrease of nerve conductivity after chronic renal failure might result from the insufficient activity of Na+-K+-ATPase and enhanced generation of free oxygen radicals.展开更多
Objective： To study the characteristics of latency of somatosensory evoked potential （SEP） and motor evoked potential （MEP） and the expression of nestin in subventricular zones （SVZ） after persistent focal cere...Objective： To study the characteristics of latency of somatosensory evoked potential （SEP） and motor evoked potential （MEP） and the expression of nestin in subventricular zones （SVZ） after persistent focal cerebral ischemia in rats. Methods： The model of cerebral ischemia in rats was made by middle cerebral artery occlusion （MCAO）. All animals of ischemia were sacrificed after 12 h, 1 d, 3 d, 7 d, and 14 d to observe the changes of latency of SEP and MEP and to detect the expression of nestin, with an immunohistochemical approach. Results： The latencies of P1 （positive wave 1）, N1 （negative wave 1） and P2 （positive wave 2） in SEP were significantly prolonged after MCAO. The latencies of N1 and N2 waves in MEP were postponed gradually and no statistical difference of latency of N1 wave was found in rats at 7 d and 14 d after MCAO. The expression of nestin increased at 12 h, and showed a significant augmentation at 3 d and peaked at 7 d, then declined slightly at 14 d after MCAO. Conclusion： The cerebral ischemia prolonged the latency of EP waves and the expression of nestin was up-regulated and reached the peak at 7 d, showing the ischemia induced the proliferation of nervous stem cells. The SEP and MEP may evaluate the proliferation in SVZ after brain ischemia.展开更多
Objective The effect of the ephedra/ephedrine alkaloid methylephedrine(dl-methylephedrine hydrochloride for testing in this paper)on cognitive related synaptic plasticity was investigated by recording extracellular fi...Objective The effect of the ephedra/ephedrine alkaloid methylephedrine(dl-methylephedrine hydrochloride for testing in this paper)on cognitive related synaptic plasticity was investigated by recording extracellular field evoked potentials and its LTP in hippocampal dentate granule cells in urethane-anaesthetized rats in vivo.Methods Single pathway recording of evoked field potentials was made from the dentate granule cells of hippocampal hemisphere in response to stimulation of the ipsilateral medial perforant path(MPP).Two parameters,the amplitude of population spike(PS amplitude)and the latency of the PS,were employed to evaluate the effects of drug on the overall changes in cellular responses.Results The present study show that methylephedrine 90 mg·kg-1 intraperitoneally,about 1/3 LD50,could increase the latency of the PS in hippocampal dentate granule cells by constant single stimulation of the MPP as the basal ransportation.However,the 30 mg·kg-1 and 10 mg·kg-1 dosage had no effect on the latency,and there are no influences of PS amplitude for all examinational groups.The methylephedrine 90 mg·kg-1 group significant enhanced the development of amplitude LTP in hippocampal dentate granule cells that induced by 60 Hz,60 pulses conditional tetanus in medial perforant path area.Also,the 30 mg·kg-1 group can promoted the maintenance of LTP induced by this tetanus,but no promotion on PS amplitude LTP appeared in this dosage and no any changes been found in 10 mg·kg-1 dosage group.Conclusions The ephedra/ephedrine alkaloid methylephedrine can modulate the synaptic plasticity in the lateral perforant path.A possible mechanism of methylephedrine on hippocampal LTP is been discussed.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFA0300600 and 2016YFA0301500)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDB07030000 and XDBS32000000)+1 种基金the National Natural Science Foundation of China(Grant Nos.11474347 and 31730039)the Fund from the Ministry of Science and Technology of China(Grant No.2015CB351701)
文摘We observed the steady-state visually evoked potential(SSVEP) from a healthy subject using a compact quad-channel potassium spin exchange relaxation-free(SERF) optically pumped magnetometer(OPM). To this end, 30 s of data were collected, and SSVEP-related magnetic responses with signal intensity ranging from 150 fT to 300 f T were observed for all four channels. The corresponding signal to noise ratio(SNR) was in the range of 3.5–5.5. We then used different channels to operate the sensor as a gradiometer. In the specific case of detecting SSVEP, we noticed that the short channel separation distance led to a strongly diminished gradiometer signal. Although not optimal for the case of SSVEP detection, this set-up can prove to be highly useful for other magnetoencephalography(MEG) paradigms that require good noise cancellation.Considering its compactness, low cost, and good performance, the K-SERF sensor has great potential for biomagnetic field measurements and brain-computer interfaces(BCI).
基金Supported by the Department of Education in Henan (2000320042)
文摘Objective:To evaluate the changes of brainstem auditory evoked potential (BAEP) in patients with delayed encephalopathy after acute carbon monoxide poisoning. Methods: BAEPs were performed in 32 controls and 40 patients. Wave Ⅰ , Ⅱ , Ⅲ ,Ⅳ, Ⅴ latencies and Ⅰ-Ⅲ , Ⅲ-Ⅴ , Ⅰ-Ⅴ interpeak latencies were measured, respectively. Results: Abnormalities of BAEPs in 13 patients (13/40, 32 ％). Among the13 abnormal BAEPs, 3 displayed prolongation of latency to waves in one side, no potential in another side; 5 displayed a similar abnormality which was bilateral prolongation of latency to waves ;and another 5 displayed unilateral latency delay. Compared wave Ⅰ , Ⅱ , Ⅲ , Ⅳ, Ⅴ latencies and Ⅰ-Ⅲ , Ⅲ-Ⅴ , Ⅰ-Ⅴ interpeak latencies in the patients and the controls, there were no significant differences (P＞0.05). Conclusion: BAEPs can be used for evaluating the diagnostic and prognostic values in the cases of delayed encephalopathy after acute carbon monoxide poisoning.
文摘Somatosensory and corticomotor evoked potentials (SSEP, CMEP) of the rats with acutely injured spinal cord were determined on the 7th, 15th, 30th, 60th, 120th and 240th day after they received implantation of the embryonic spinal cord from 14-day rat embryo into the injured cord. The motor functions of the hindlimbs were also observed. The rats with acute spinal cord injury and those with cord injury treated with the implantation of a piece of skeletal muscle served as the controls. It was found that the motor functions were recovered on the 30th day after implantation but the latent period of both SSEP and CMEP returned to mormal on the 240th day. At that time,the latent period of SSEP and CMEP of the 2 control groups also recovered gradually. It is believed that embryonic spinal cord implantation can affect the recovery of the motor functions of the rats. But more sophisticated methods are needed to clarify the interrelationship of the host cord with the grafts.
文摘Somatasensory evoked potentials (SEP), sciatic nerve conduction velocity (CV), sciatic nerve Na+-K+-ATPase activity, and lipid peroxide content (LPO) were determined in 8 rats with chronic renal failure induced with 5/6 nephrectomy. Meanwhile, the histological changes were also oserved. Ten rats wtih sham operation served as the control. It was found that in the group with chronic renal failure, the mean peak latency of SEP was significantly prolonged and CV slower than those of the control. In the sciatic nerve tissue, Na+-K+-ATPase activity was loyer and LPO content higher in the tested group than in the control. No significant histological changes of the sciatic nerve were found under optical microscope. These findings suggest that the decrease of nerve conductivity after chronic renal failure might result from the insufficient activity of Na+-K+-ATPase and enhanced generation of free oxygen radicals.
基金Supported by Special Funds for Excellent Persons of Sichuan Province(05ZQ026-020)Key Program of Science and Technology of Sichuan Province(05SG1866)
文摘Objective： To study the characteristics of latency of somatosensory evoked potential （SEP） and motor evoked potential （MEP） and the expression of nestin in subventricular zones （SVZ） after persistent focal cerebral ischemia in rats. Methods： The model of cerebral ischemia in rats was made by middle cerebral artery occlusion （MCAO）. All animals of ischemia were sacrificed after 12 h, 1 d, 3 d, 7 d, and 14 d to observe the changes of latency of SEP and MEP and to detect the expression of nestin, with an immunohistochemical approach. Results： The latencies of P1 （positive wave 1）, N1 （negative wave 1） and P2 （positive wave 2） in SEP were significantly prolonged after MCAO. The latencies of N1 and N2 waves in MEP were postponed gradually and no statistical difference of latency of N1 wave was found in rats at 7 d and 14 d after MCAO. The expression of nestin increased at 12 h, and showed a significant augmentation at 3 d and peaked at 7 d, then declined slightly at 14 d after MCAO. Conclusion： The cerebral ischemia prolonged the latency of EP waves and the expression of nestin was up-regulated and reached the peak at 7 d, showing the ischemia induced the proliferation of nervous stem cells. The SEP and MEP may evaluate the proliferation in SVZ after brain ischemia.
文摘Objective The effect of the ephedra/ephedrine alkaloid methylephedrine(dl-methylephedrine hydrochloride for testing in this paper)on cognitive related synaptic plasticity was investigated by recording extracellular field evoked potentials and its LTP in hippocampal dentate granule cells in urethane-anaesthetized rats in vivo.Methods Single pathway recording of evoked field potentials was made from the dentate granule cells of hippocampal hemisphere in response to stimulation of the ipsilateral medial perforant path(MPP).Two parameters,the amplitude of population spike(PS amplitude)and the latency of the PS,were employed to evaluate the effects of drug on the overall changes in cellular responses.Results The present study show that methylephedrine 90 mg·kg-1 intraperitoneally,about 1/3 LD50,could increase the latency of the PS in hippocampal dentate granule cells by constant single stimulation of the MPP as the basal ransportation.However,the 30 mg·kg-1 and 10 mg·kg-1 dosage had no effect on the latency,and there are no influences of PS amplitude for all examinational groups.The methylephedrine 90 mg·kg-1 group significant enhanced the development of amplitude LTP in hippocampal dentate granule cells that induced by 60 Hz,60 pulses conditional tetanus in medial perforant path area.Also,the 30 mg·kg-1 group can promoted the maintenance of LTP induced by this tetanus,but no promotion on PS amplitude LTP appeared in this dosage and no any changes been found in 10 mg·kg-1 dosage group.Conclusions The ephedra/ephedrine alkaloid methylephedrine can modulate the synaptic plasticity in the lateral perforant path.A possible mechanism of methylephedrine on hippocampal LTP is been discussed.
文摘目的研究不同刺激声在坐姿下诱发的前庭诱发肌源性电位(vestibular-evoked myogenic potentials,VEMPs)特征,提供各波潜伏期及振幅等参数的正常值参考范围。方法分别用500 Hz短纯音(tone-burst)及500 Hz线性调频脉冲音(CE-chirp)两种刺激声对21名(男11人,女10人)听力正常且无耳蜗及前庭系统疾病的青年人(年龄22~33岁,平均年龄23.95±3.29岁)进行VEMPs测试,测试起始强度为110 dB nHL,以5 dB为步阶测试至阈值,记录各强度参数,并进行分析。结果两种刺激声坐姿下诱发的cVEMP及oVEMP阈值分别为tone-burst cVEMP 85.00±6.10 dB nHL,CE-chirp cVEMP 84.63±4.99 dB nHL;tone-burst oVEMP 83.38±6.54 dB nHL,CE-chirp oVEMP 82.50±6.20 dB nHL。两种刺激声测得的各强度p1潜伏期、n1潜伏期有显著差异(P<0.05),p1-n1波间期、p1-n1振幅、双侧不对称性、双侧振幅比、双侧对称系数等均无显著差异(P>0.05)。结论坐姿下正常青年人两种刺激声给声强度100 dB nHL时VEMPs的引出率均为100%,500 Hz线性调频脉冲音可作为VEMPs测试的刺激声应用于临床,评估椭圆囊和球囊功能。
