The effects of acupuncture on the sensory evoked cortical potentials were investigated in 31 rabbits anaesthetized with urethane of conscious, so as to see what happened to the functional state of cerebral cortex in t...The effects of acupuncture on the sensory evoked cortical potentials were investigated in 31 rabbits anaesthetized with urethane of conscious, so as to see what happened to the functional state of cerebral cortex in the meantime. The visual, auditory and somatosensory evoked potentials as well as raw EEGs were recorded from the animal’s scalp. In most cases, an electro-acupuncture instrument was used instead of manual acupuncture. The main component amplitudes of evoked potentials,the frequency band powers and the total integral values of raw EEGs were analyzed. Results showed that during acupuncture the main components of evoked potentials were significantly depressed and the raw EEGs appeared desynchronized while the experimental animals were slightly activated. Moreover,both the total integral values of raw EEGs and the powers of lower frequency waves (1 - 3. 99 Hz)were decreased and positively correlated well with the amplitudes of main components of the evoked potentials. Therefore, the possibility that the effects of acupuncture on the evoked potentials are secondary to the changes of raw EEGs remains to be ruled out, and it is suggested that the inhibition of evoked potentials during acupuncture does not necessarily mean that the cerebral cortex is in an inhibitory展开更多
The role of the ipsilaterally descending motor pathways in the recovery mechanisms after unilateral hemispheric damage is still poorly understood. Motor output reorganization was investigated in a 56-year-old male pat...The role of the ipsilaterally descending motor pathways in the recovery mechanisms after unilateral hemispheric damage is still poorly understood. Motor output reorganization was investigated in a 56-year-old male patient with acquired unilateral hemispheric atrophy due to Rasmussen encephalitis. In particular,the ipsilateral corticospinal pathways were explored using focal transcranial magnetic stimulation. In the first dorsal interosseous and wrist extensors muscles, the median amplitudes of the ipsilateral motor evoked potentials induced by transcranial magnetic stimulation in the patient were higher than those of 10 age-matched healthy control subjects. In the biceps brachii muscle, the median amplitudes of the ipsilateral motor evoked potentials were the second largest in the patient compared to the controls. This study demonstrated a reinforcement of ipsilateral motor projections from the unaffected motor cortex to the hemiparetic hand in a subject with acquired unihemispheric cortical damage.展开更多
The peripheral driver stimulating theory states that as a driver passes along a certain meridian during acupuncture; the driver provokes nerve sense devices along the meridian, resulting in the nerve impulse entering ...The peripheral driver stimulating theory states that as a driver passes along a certain meridian during acupuncture; the driver provokes nerve sense devices along the meridian, resulting in the nerve impulse entering the central nervous system. Accordingly, volunteers have reported propagated sensations along the meridians （PSM）. The present study was designed to utilize a cortical somatosensory-evoked potential （CSEP） topographic map for determining whether stimulation expansion occurs in somatosensory area I when sensation was provoked in individuals with obvious PSM. The sensation was blocked by mechanical compression, and the sensation was imitated in individuals without PSM. Results revealed a red, high-potential signal in the representative area of the lower limbs in individuals with obvious PSM symptoms when the Gall Bladder Meridian （GBM） sensation passed to the head and face. This representative area was near the middle line of the CSEP topographic map, and a red, high-potential signal, which jumps over the representative area of the upper limbs, also appeared in the representative face area, which was at the external region of the CSEP topographic map. However, in individuals exhibiting no PSM, only a red high-potential signal appeared in the representative lower limb area. When Hegu （LI 4） was stimulated in individuals without PSM, an obvious evoked response appeared only in the representative upper limb area. However, when Hegu was stimulated in individuals exhibiting PSM, the response area was larger in the representative upper limb area and extended to the representative face area. When Guangrning （GB 37） was stimulated in PSM individuals, the face representation response disappeared and was confined to a foot representation of the somatosensory area I when PSM was blocked by mechanical pressure. Results suggested that mechanical compression blocked PSM, and corresponding changes were exhibited in the CSEP topographic map. These results provide compelling evidence for the hypothesis that peripheral driver stimulation is the key element in producing PSM.展开更多
AIM: To study a novel technique to record spinal and cortical evoked potentials (EPs) simultaneously in response to electrical stimulation in the human rectum. METHODS: Eight male and nine female healthy volunteers pa...AIM: To study a novel technique to record spinal and cortical evoked potentials (EPs) simultaneously in response to electrical stimulation in the human rectum. METHODS: Eight male and nine female healthy volunteers participated. Stimulating electrodes were attached to the rectal mucosa at 15 cm and 12 cm above the dentate line. Recording skin electrodes were positioned over vertebrae L4 through S2. The electrical stimulus was a square wave of 0.2 ms duration and the intensity of the stimulus varied between 0 and 100 mA. EP responses were recorded using a Nicolet Viking IV programmable signal conditioner.RESULTS: Simultaneous recording of cortical and spinal EPs was obtained in > 80% of the trials. The EP responses increased with the intensity of the electrical stimulation, were reproducible overtime, and were blocked by application of Lidocaine jelly at the site of stimulation. The morphology (N1/P1), mean ± SD for latency (spinal N1, 4.6 ± 0.4 ms; P1, 6.8 ± 0.5 ms; cortical N1, 136.1 ± 4.2 ms; P1, 233.6 ± 12.8 ms) and amplitude (N1/P1, spinal, 38 ± 7 μV; cortical 19 ± 3 μV) data for the EP responses were consistent with those in the published literature. Reliable and reproducible EP recordings were obtained with the attachment of the electrodes to the rectal mucosa at predetermined locations between 16 and 8 cm above the anal verge, and the distance between the attachment sites of the electrodes (the optimal distance being approximately 3.0 cm between the two electrodes). CONCLUSION: This technique can be used to assess potential abnormalities in primary afferent neural pathways innervating the rectum in several neurodegenerative and functional pain disorders.展开更多
BACKGROUND: It has been shown that although brain does not contain lining endothelial lymphatic vessel, it has lymphatic drain. Anterior lymphatic system of lymphatic vessel in brain tissue plays a key role in introdu...BACKGROUND: It has been shown that although brain does not contain lining endothelial lymphatic vessel, it has lymphatic drain. Anterior lymphatic system of lymphatic vessel in brain tissue plays a key role in introducing brain interstitial fluid to lymphatic system; however, the significance of lymphatic drain and the effect on cerebral edema remains unclear. OBJECTIVE: To investigate the effect of cerebral lymphatic block on cerebral morphology and cortical evoked potential in rats. DESIGN: Randomized controlled animal study. SETTING: Institute of Cerebral Microcirculation of Taishan Medical College and Department of Neurology of Affiliated Hospital. MATERIALS: A total of 63 healthy adult male Wistar rats weighing 300-350 g were selected in this study. Forty-seven rats were used for the morphological observation induced by lymphatic drain and randomly divided into three groups: general observation group (n =12), light microscopic observation group (n =21) and electronic microscopic observation group (n =14). The rats in each group were divided into cerebral lymphatic block subgroup and sham-operation control subgroup. Sixteen rats were used for observing the effect of cerebral lymphatic block on cortical evoked potential, in which the animals were randomly divided into sham-operation group (n =6) and cerebral lymphatic block group (n =10). METHODS: The experiment was carried out in the Institute of Cerebral Microcirculation of Taishan Medical College from January to August 2003. Rats in cerebral lymphatic block group were anesthetized and separated bilateral superficial and deep cervical lymph nodes under sterile condition. Superior and inferior boarders of lymph nodes were ligated the inputting and outputting channels, respectively, and then lymph node was removed so as to establish cerebral lymphatic drain disorder models. Rats in sham-operation control group were not ligated the lymphatic vessel and removed lymph nodes, and other operations were as the same as those in cerebral lymphatic block group. Morphological changes of the brain and alterations of latency of cortical evoked potential were detected on the 1st, 2nd, 3rd, 5th, 7th, 10th and 15th days after operation under general, light microscope and electronic microscope observations. MAIN OUTCOME MEASURES: ① Cerebral morphological changes; ② latent changes of cortical evoked potential. RESULTS: A total of 63 rats were involved in the final analysis. ① Cerebral morphological changes: General observation showed that, for cerebral lymphatic block rats, the surface of brain was pale and full, and cerebral gyrus was wide and flattened sulci after cerebral lymphatic block; and cerebral tissue space prolongation, increased interstitial fluid, neuronal degeneration and necrosis, diffused phagocytes and satellitosis were observed under light microscope. Neuronal swell and necrosis, glial cell swell, apparent subcellular changes such as mitochondron were observed under electronic microscope. ② Latent changes of cortical evoked potential: As compared with sham-operation control group, latency of cortical evoked potential in cerebral lymphatic blockage group prolonged on the 5th day and 7th day after cerebral lymphatic block [(6.28±0.23), (6.97±0.35) ms; (6.23±0.22), (7.12±0.20) ms; P < 0.01]. CONCLUSION: ① Cerebral lymphatic block plays an important role in cerebral morphology, and may result in abnormality of sensitive impulse conduction and prolong latency of cortical evoked potential. ② Examination of cortical evoked potential is easy and convenient, so it is regarded as a key index for lymphatic disturbed cerebral injury.展开更多
Interleukin-6 has been shown to be involved in nerve injury and nerve regeneration, but the effects of long-term administration of high concentrations of interleukin-6 on neurons in the central nervous system is poorl...Interleukin-6 has been shown to be involved in nerve injury and nerve regeneration, but the effects of long-term administration of high concentrations of interleukin-6 on neurons in the central nervous system is poorly understood. This study investigated the effects of 24 hour expo-sure of interleukin-6 on cortical neurons at various concentrations （0.1, 1, 5 and 10 ng/mL） and the effects of 10 ng/mL interleukin-6 exposure to cortical neurons for various durations （2, 4, 8, 24 and 48 hours） by studying voltage-gated Na＋ channels using a patch-clamp technique. Volt-age-clamp recording results demonstrated that interleukin-6 suppressed Na＋ currents through its receptor in a time- and dose-dependent manner, but did not alter voltage-dependent activation and inactivation. Current-clamp recording results were consistent with voltage-clamp recording results. Interleukin-6 reduced the action potential amplitude of cortical neurons, but did not change the action potential threshold. The regulation of voltage-gated Na＋channels in rat corti-cal neurons by interleukin-6 is time- and dose-dependent.展开更多
Cortical spreading depression(CSD)is a pathophysiological phenomenon.There are sufficient evidences to prove that CSD plays an important role in some neurological disorders.However,exact mechanisms of its initiation a...Cortical spreading depression(CSD)is a pathophysiological phenomenon.There are sufficient evidences to prove that CSD plays an important role in some neurological disorders.However,exact mechanisms of its initiation and propagation are still unclear.Previous studies showed that glutamate receptors could be concerned with CSD,but those studies were mostly performed oriented to ionotropic glutamate receptors(iGluRs).There is relatively little report about effects of metabotropic glutamate receptors(mGluRs)on CSD.Here,we applied optical intrinsic signal imaging(OISI)combined with direct current(DC)potential recording to examine influences of some mGluRs antagonist(or agonist)on CSD propagation in rat’s brain,to indirectly validate actions of some mGluRs on CSD.We found that N-acetyl-l-aspartyl-l-glutamate(NAAG,an agonist at mGluR3)inhibited the propagation of CSD,and the inhibition was gradually developed with time.However,6-methyl-2-phenylethynyl-pyridine(MPEP,an antagonist of mGluR5)did not produce any significant alterations with the CSD propagation.Our findings suggest that mGluR3 could play an important role in the CSD propagation,but the activity of mGluR5 was comparatively weak.These findings can help to understand the propagation mechanism of CSD,and consider the therapy of some neurological diseases involved with CSD.展开更多
Background:Visual cortex neurons often respond to stimuli very differently on repeated trials.This trial-by-trial variability is known to be correlated among nearby neurons.Our long-term goal is to quantitatively esti...Background:Visual cortex neurons often respond to stimuli very differently on repeated trials.This trial-by-trial variability is known to be correlated among nearby neurons.Our long-term goal is to quantitatively estimate neuronal response variability,using multi-channel local field potential(LFP)data from single trials.Methods:Acute experiments were performed with anesthetized(Remifentanil,Propofol,nitrous oxide)and paralyzed(Gallamine Triethiodide)cats.Computer-controlled visual stimuli were displayed on a gamma-corrected CRT monitor.For the principal experiment,two kinds of visual stimuli were used:drifting sine-wave gratings,and a uniform mean-luminance gray screen.These two stimuli were each delivered monocularly for 100 sec in a random order,for 10 trials.Multi-unit activity(MUA)and LFP signals were extracted from broadband raw data acquired from Area 17 and 18 using A1X32 linear arrays(NeuroNexus)and the OpenEphys recording system.LFP signal processing was performed using Chronux,an open-source MATLAB toolbox.Current source density(CSD)analysis was performed on responses to briefly flashed full-field stimuli using the MATLAB toolbox,CSDplotter.The common response variability(global noise)of MUA was estimated using the model proposed by Scholvinck et al.[2015].Results:On different trials,a given neuron responded with different firing to the same visual stimuli.Within one trial,a neuron’s firing rate also fluctuated across successive cycles of a drifting grating.When the animal was given extra anesthesia,neurons fired in a desynchronized pattern;with lighter levels of anesthesia,neuronal firing because more synchronized.By examining the cross-correlations of LFP signals recorded from different cortical layers,we found LFP signals could be divided to two groups:those recorded in layer IV and above,and those from layers V and VI.Within each group,LFP signals recorded by different channels are highly correlated.These two groups were observed in lighter and deeper anesthetized animals,also in sine-wave and uniform gray stimulus conditions.We also investigated correlations between LFP signals and global noise.Power in the LFP beta band was highly correlated with global noise,when animals were in deeper anesthesia.Conclusions:Brain states contribute to variations in neuronal responses.Raw LFP correlation results suggest that we should analyze LFP data according to their laminar organization.Correlation of low-frequency LFP under deeper anesthesia with global noise gives us some insight to predict noise from single-trial data,and we hope to extend this analysis to lighter anesthesia in the future.展开更多
文摘The effects of acupuncture on the sensory evoked cortical potentials were investigated in 31 rabbits anaesthetized with urethane of conscious, so as to see what happened to the functional state of cerebral cortex in the meantime. The visual, auditory and somatosensory evoked potentials as well as raw EEGs were recorded from the animal’s scalp. In most cases, an electro-acupuncture instrument was used instead of manual acupuncture. The main component amplitudes of evoked potentials,the frequency band powers and the total integral values of raw EEGs were analyzed. Results showed that during acupuncture the main components of evoked potentials were significantly depressed and the raw EEGs appeared desynchronized while the experimental animals were slightly activated. Moreover,both the total integral values of raw EEGs and the powers of lower frequency waves (1 - 3. 99 Hz)were decreased and positively correlated well with the amplitudes of main components of the evoked potentials. Therefore, the possibility that the effects of acupuncture on the evoked potentials are secondary to the changes of raw EEGs remains to be ruled out, and it is suggested that the inhibition of evoked potentials during acupuncture does not necessarily mean that the cerebral cortex is in an inhibitory
文摘The role of the ipsilaterally descending motor pathways in the recovery mechanisms after unilateral hemispheric damage is still poorly understood. Motor output reorganization was investigated in a 56-year-old male patient with acquired unilateral hemispheric atrophy due to Rasmussen encephalitis. In particular,the ipsilateral corticospinal pathways were explored using focal transcranial magnetic stimulation. In the first dorsal interosseous and wrist extensors muscles, the median amplitudes of the ipsilateral motor evoked potentials induced by transcranial magnetic stimulation in the patient were higher than those of 10 age-matched healthy control subjects. In the biceps brachii muscle, the median amplitudes of the ipsilateral motor evoked potentials were the second largest in the patient compared to the controls. This study demonstrated a reinforcement of ipsilateral motor projections from the unaffected motor cortex to the hemiparetic hand in a subject with acquired unihemispheric cortical damage.
基金the National Natural Science Foundation of China, No.30973720the Science Research Foundation of Ministry of Health & United Fujian Provincial Health and Education Project for Tackling the Key Research of China, No.WKJ2005-2-004
文摘The peripheral driver stimulating theory states that as a driver passes along a certain meridian during acupuncture; the driver provokes nerve sense devices along the meridian, resulting in the nerve impulse entering the central nervous system. Accordingly, volunteers have reported propagated sensations along the meridians （PSM）. The present study was designed to utilize a cortical somatosensory-evoked potential （CSEP） topographic map for determining whether stimulation expansion occurs in somatosensory area I when sensation was provoked in individuals with obvious PSM. The sensation was blocked by mechanical compression, and the sensation was imitated in individuals without PSM. Results revealed a red, high-potential signal in the representative area of the lower limbs in individuals with obvious PSM symptoms when the Gall Bladder Meridian （GBM） sensation passed to the head and face. This representative area was near the middle line of the CSEP topographic map, and a red, high-potential signal, which jumps over the representative area of the upper limbs, also appeared in the representative face area, which was at the external region of the CSEP topographic map. However, in individuals exhibiting no PSM, only a red high-potential signal appeared in the representative lower limb area. When Hegu （LI 4） was stimulated in individuals without PSM, an obvious evoked response appeared only in the representative upper limb area. However, when Hegu was stimulated in individuals exhibiting PSM, the response area was larger in the representative upper limb area and extended to the representative face area. When Guangrning （GB 37） was stimulated in PSM individuals, the face representation response disappeared and was confined to a foot representation of the somatosensory area I when PSM was blocked by mechanical pressure. Results suggested that mechanical compression blocked PSM, and corresponding changes were exhibited in the CSEP topographic map. These results provide compelling evidence for the hypothesis that peripheral driver stimulation is the key element in producing PSM.
基金Supported by Grants from the National Institutes of Health M01-RR-00042UL1RR024986 (to Wiley JW)
文摘AIM: To study a novel technique to record spinal and cortical evoked potentials (EPs) simultaneously in response to electrical stimulation in the human rectum. METHODS: Eight male and nine female healthy volunteers participated. Stimulating electrodes were attached to the rectal mucosa at 15 cm and 12 cm above the dentate line. Recording skin electrodes were positioned over vertebrae L4 through S2. The electrical stimulus was a square wave of 0.2 ms duration and the intensity of the stimulus varied between 0 and 100 mA. EP responses were recorded using a Nicolet Viking IV programmable signal conditioner.RESULTS: Simultaneous recording of cortical and spinal EPs was obtained in > 80% of the trials. The EP responses increased with the intensity of the electrical stimulation, were reproducible overtime, and were blocked by application of Lidocaine jelly at the site of stimulation. The morphology (N1/P1), mean ± SD for latency (spinal N1, 4.6 ± 0.4 ms; P1, 6.8 ± 0.5 ms; cortical N1, 136.1 ± 4.2 ms; P1, 233.6 ± 12.8 ms) and amplitude (N1/P1, spinal, 38 ± 7 μV; cortical 19 ± 3 μV) data for the EP responses were consistent with those in the published literature. Reliable and reproducible EP recordings were obtained with the attachment of the electrodes to the rectal mucosa at predetermined locations between 16 and 8 cm above the anal verge, and the distance between the attachment sites of the electrodes (the optimal distance being approximately 3.0 cm between the two electrodes). CONCLUSION: This technique can be used to assess potential abnormalities in primary afferent neural pathways innervating the rectum in several neurodegenerative and functional pain disorders.
文摘BACKGROUND: It has been shown that although brain does not contain lining endothelial lymphatic vessel, it has lymphatic drain. Anterior lymphatic system of lymphatic vessel in brain tissue plays a key role in introducing brain interstitial fluid to lymphatic system; however, the significance of lymphatic drain and the effect on cerebral edema remains unclear. OBJECTIVE: To investigate the effect of cerebral lymphatic block on cerebral morphology and cortical evoked potential in rats. DESIGN: Randomized controlled animal study. SETTING: Institute of Cerebral Microcirculation of Taishan Medical College and Department of Neurology of Affiliated Hospital. MATERIALS: A total of 63 healthy adult male Wistar rats weighing 300-350 g were selected in this study. Forty-seven rats were used for the morphological observation induced by lymphatic drain and randomly divided into three groups: general observation group (n =12), light microscopic observation group (n =21) and electronic microscopic observation group (n =14). The rats in each group were divided into cerebral lymphatic block subgroup and sham-operation control subgroup. Sixteen rats were used for observing the effect of cerebral lymphatic block on cortical evoked potential, in which the animals were randomly divided into sham-operation group (n =6) and cerebral lymphatic block group (n =10). METHODS: The experiment was carried out in the Institute of Cerebral Microcirculation of Taishan Medical College from January to August 2003. Rats in cerebral lymphatic block group were anesthetized and separated bilateral superficial and deep cervical lymph nodes under sterile condition. Superior and inferior boarders of lymph nodes were ligated the inputting and outputting channels, respectively, and then lymph node was removed so as to establish cerebral lymphatic drain disorder models. Rats in sham-operation control group were not ligated the lymphatic vessel and removed lymph nodes, and other operations were as the same as those in cerebral lymphatic block group. Morphological changes of the brain and alterations of latency of cortical evoked potential were detected on the 1st, 2nd, 3rd, 5th, 7th, 10th and 15th days after operation under general, light microscope and electronic microscope observations. MAIN OUTCOME MEASURES: ① Cerebral morphological changes; ② latent changes of cortical evoked potential. RESULTS: A total of 63 rats were involved in the final analysis. ① Cerebral morphological changes: General observation showed that, for cerebral lymphatic block rats, the surface of brain was pale and full, and cerebral gyrus was wide and flattened sulci after cerebral lymphatic block; and cerebral tissue space prolongation, increased interstitial fluid, neuronal degeneration and necrosis, diffused phagocytes and satellitosis were observed under light microscope. Neuronal swell and necrosis, glial cell swell, apparent subcellular changes such as mitochondron were observed under electronic microscope. ② Latent changes of cortical evoked potential: As compared with sham-operation control group, latency of cortical evoked potential in cerebral lymphatic blockage group prolonged on the 5th day and 7th day after cerebral lymphatic block [(6.28±0.23), (6.97±0.35) ms; (6.23±0.22), (7.12±0.20) ms; P < 0.01]. CONCLUSION: ① Cerebral lymphatic block plays an important role in cerebral morphology, and may result in abnormality of sensitive impulse conduction and prolong latency of cortical evoked potential. ② Examination of cortical evoked potential is easy and convenient, so it is regarded as a key index for lymphatic disturbed cerebral injury.
基金supported by a grant from the National Natural Science Foundation of China,No.30972766,31170852,81001322,81172795,81173048the Specialized Research Fund for the Doctoral Program of Colleges and Universities,No.20094402110004
文摘Interleukin-6 has been shown to be involved in nerve injury and nerve regeneration, but the effects of long-term administration of high concentrations of interleukin-6 on neurons in the central nervous system is poorly understood. This study investigated the effects of 24 hour expo-sure of interleukin-6 on cortical neurons at various concentrations （0.1, 1, 5 and 10 ng/mL） and the effects of 10 ng/mL interleukin-6 exposure to cortical neurons for various durations （2, 4, 8, 24 and 48 hours） by studying voltage-gated Na＋ channels using a patch-clamp technique. Volt-age-clamp recording results demonstrated that interleukin-6 suppressed Na＋ currents through its receptor in a time- and dose-dependent manner, but did not alter voltage-dependent activation and inactivation. Current-clamp recording results were consistent with voltage-clamp recording results. Interleukin-6 reduced the action potential amplitude of cortical neurons, but did not change the action potential threshold. The regulation of voltage-gated Na＋channels in rat corti-cal neurons by interleukin-6 is time- and dose-dependent.
基金This work is supported by the National High Technology Research and Development Program of China(Grant No.2007AA02Z303)the National Natural Science Foundation of China(Grant No.30970964,30801482,30800313)+1 种基金the Program for New Century Excellent Talents in University(Grant No.NCET-08-0213)the Ph.D.Programs Foundation of Ministry of Education of China(Grant No.20070487058,20090142110054).
文摘Cortical spreading depression(CSD)is a pathophysiological phenomenon.There are sufficient evidences to prove that CSD plays an important role in some neurological disorders.However,exact mechanisms of its initiation and propagation are still unclear.Previous studies showed that glutamate receptors could be concerned with CSD,but those studies were mostly performed oriented to ionotropic glutamate receptors(iGluRs).There is relatively little report about effects of metabotropic glutamate receptors(mGluRs)on CSD.Here,we applied optical intrinsic signal imaging(OISI)combined with direct current(DC)potential recording to examine influences of some mGluRs antagonist(or agonist)on CSD propagation in rat’s brain,to indirectly validate actions of some mGluRs on CSD.We found that N-acetyl-l-aspartyl-l-glutamate(NAAG,an agonist at mGluR3)inhibited the propagation of CSD,and the inhibition was gradually developed with time.However,6-methyl-2-phenylethynyl-pyridine(MPEP,an antagonist of mGluR5)did not produce any significant alterations with the CSD propagation.Our findings suggest that mGluR3 could play an important role in the CSD propagation,but the activity of mGluR5 was comparatively weak.These findings can help to understand the propagation mechanism of CSD,and consider the therapy of some neurological diseases involved with CSD.
文摘Background:Visual cortex neurons often respond to stimuli very differently on repeated trials.This trial-by-trial variability is known to be correlated among nearby neurons.Our long-term goal is to quantitatively estimate neuronal response variability,using multi-channel local field potential(LFP)data from single trials.Methods:Acute experiments were performed with anesthetized(Remifentanil,Propofol,nitrous oxide)and paralyzed(Gallamine Triethiodide)cats.Computer-controlled visual stimuli were displayed on a gamma-corrected CRT monitor.For the principal experiment,two kinds of visual stimuli were used:drifting sine-wave gratings,and a uniform mean-luminance gray screen.These two stimuli were each delivered monocularly for 100 sec in a random order,for 10 trials.Multi-unit activity(MUA)and LFP signals were extracted from broadband raw data acquired from Area 17 and 18 using A1X32 linear arrays(NeuroNexus)and the OpenEphys recording system.LFP signal processing was performed using Chronux,an open-source MATLAB toolbox.Current source density(CSD)analysis was performed on responses to briefly flashed full-field stimuli using the MATLAB toolbox,CSDplotter.The common response variability(global noise)of MUA was estimated using the model proposed by Scholvinck et al.[2015].Results:On different trials,a given neuron responded with different firing to the same visual stimuli.Within one trial,a neuron’s firing rate also fluctuated across successive cycles of a drifting grating.When the animal was given extra anesthesia,neurons fired in a desynchronized pattern;with lighter levels of anesthesia,neuronal firing because more synchronized.By examining the cross-correlations of LFP signals recorded from different cortical layers,we found LFP signals could be divided to two groups:those recorded in layer IV and above,and those from layers V and VI.Within each group,LFP signals recorded by different channels are highly correlated.These two groups were observed in lighter and deeper anesthetized animals,also in sine-wave and uniform gray stimulus conditions.We also investigated correlations between LFP signals and global noise.Power in the LFP beta band was highly correlated with global noise,when animals were in deeper anesthesia.Conclusions:Brain states contribute to variations in neuronal responses.Raw LFP correlation results suggest that we should analyze LFP data according to their laminar organization.Correlation of low-frequency LFP under deeper anesthesia with global noise gives us some insight to predict noise from single-trial data,and we hope to extend this analysis to lighter anesthesia in the future.
