Although extensively studied, the exact role of sleep in learning and memory is still not very clear. Sleep deprivation has been most frequently used to explore the effects of sleep on learning and memory, but the results from such studies are inevitably complicated by concurrent stress and distress. Furthermore, it is not clear whether there is a strict time-window between sleep and memory consolidation. In the present study we were able to induce time-locked slow-wave sleep (SWS) in mice by optogenetically stimulating GABAergic neurons in the parafacial zone (PZ), providing a direct approach to analyze the influences of SWS on learning and memory with precise time-windows. We found that SWS induced by light for 30 min immediately or 15 min after the training phase of the object-in-place task significantly prolonged the memory from 30 min to 6 h. However, induction of SWS 30 min after the training phase did not improve memory, suggesting a critical time-window between the induction of a brief episode of SWS and learning for memory consolidation. Application of a gentle touch to the mice during light stimulation to prevent SWS induction also failed to improve memory, indicating the specific role of SWS, but not the activation of PZ GABAergic neurons itself, in memory consolidation. Similar influences of light-induced SWS on memory consolidation also occurred for Y-maze spatial memory and contextual fear memory, but not for cued fear memory. SWS induction immediately before the test phase had no effect on memory performance, indicating that SWS does not affect memory retrieval. Thus, by induction of a brief-episode SWS we have revealed a critical time window for the consolidation of hippocampus-dependent memory.
Animals ; Cues ; Electroencephalography ; Electromyography ; Evoked Potentials, Motor ; physiology ; Fear ; psychology ; Glutamate Decarboxylase ; metabolism ; Hippocampus ; physiology ; Light ; Luminescent Proteins ; genetics ; metabolism ; Maze Learning ; physiology ; Memory Consolidation ; physiology ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Sleep Deprivation ; Sleep, Slow-Wave ; physiology ; Time Factors ; Vesicular Inhibitory Amino Acid Transport Proteins ; genetics ; metabolism

OBJECTIVETo investigate the effect of electrical stimulation to sacral spinal nerve 3 (S₃ stimulation) on gastrointestinal dysfunction after spinal cord injury (SCI).

METHODSSix rabbits were taken as normal controls to record their gastrointestinal multipoint biological discharge, colon pressure and rectoanal inhibitory reflex. Electrodes were implanted into S₃ in another 18 rabbits. Then the model of SCI was conducted following Fehling's method: the rabbit S₃ was clamped to induce transverse injury, which was claimed by both somatosensory evoked potential and motion evoked potential. Two hours after SCI, S₃ stimulation was conducted. The 18 rabbits were subdivided into 3 groups to respectively record their gastrointestinal electric activities (n=6), colon pressure (n=6), and rectum pressure (n=6). Firstly the wave frequency was fixed at 15 Hz and pulse width at 400 μs and three stimulus intensities (6 V, 8 V, 10 V) were tested. Then the voltage was fixed at 6 V and the pulse width changed from 200 μs, 400 μs to 600 μs. The response was recorded and analyzed. The condition of defecation was also investigated.

RESULTSAfter SCI, the mainly demonstrated change was dyskinesia of the single haustrum and distal colon. The rectoanal inhibitory reflex almost disappeared. S₃ stimulation partly recovered the intestinal movement after denervation, promoting defecation. The proper stimulus parameters were 15 Hz, 400 μs, 6 V, 10 s with 20 s intervals and 10 min with 10 min intervals, total 2 h.

CONCLUSIONS₃ stimulation is able to restore the intestinal movement after denervation (especially single haustrum and distal colon), which promotes defecation.

Animals ; Disease Models, Animal ; Electric Stimulation ; Electrodes, Implanted ; Evoked Potentials, Motor ; physiology ; Evoked Potentials, Somatosensory ; physiology ; Gastrointestinal Tract ; physiopathology ; Rabbits ; Sacrum ; innervation ; Spinal Cord Injuries ; physiopathology

PURPOSE: To evaluate whether intraoperative neurophysiologic monitoring (IONM) with combined muscle motor evoked potentials (mMEPs) and somatosensory evoked potentials is useful for more aggressive and safe resection in intramedullary spinal cord tumour (IMSCT) surgery. MATERIALS AND METHODS: We reviewed data from consecutive patients who underwent surgery for IMSCT between 1998 and April 2012. The patients were divided into two groups based on whether or not IONM was applied. In the monitored group, the procedures were performed under IONM using 75% muscle amplitude decline weaning criteria. The control group was comprised of patients who underwent IMSCT surgery without IONM. The primary outcome was the rate of gross total excision of the tumour on magnetic resonance imaging at one week after surgery. The secondary outcome was the neurologic outcome based on the McCormick Grade scale. RESULTS: The two groups had similar demographics. The total gross removal tended to increase when intraoperative neurophysiologic monitoring was used, but this tendency did not reach statistical significance (76% versus 58%; univariate analysis, p=0.049; multivariate regression model, p=0.119). The serial McCormick scale score was similar between the two groups (based on repeated measure ANOVA). CONCLUSION: Our study evaluated combined IONM of trans-cranial electrical (Tce)-mMEPs and SEPs for IMSCT. During IMSCT surgery, combined Tce-mMEPs and SEPs using 75% muscle amplitude weaning criteria did not result in significant improvement in the rate of gross total excision of the tumour or neurologic outcome.
Adult ; Evoked Potentials, Motor/physiology ; Evoked Potentials, Somatosensory/*physiology ; Female ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Spinal Cord Neoplasms/*surgery

The recent developments of new devices and advances in anesthesiology have greatly improved the utility and accuracy of intraoperative neurophysiological monitoring (IOM). Herein, we review the basic principles of the electrophysiological methods employed under IOM in the operating room. These include motor evoked potentials, somatosensory evoked potentials, electroencephalography, electromyography, brainstem auditory evoked potentials, and visual evoked potentials. Most of these techniques have certain limitations and their utility is still being debated. In this review, we also discuss the optimal stimulation/recording method for each of these modalities during individual surgeries as well as the diverse criteria for alarm signs.
Electroencephalography ; Electromyography ; Evoked Potentials, Motor/physiology ; Evoked Potentials, Somatosensory/physiology ; Humans ; Intraoperative Neurophysiological Monitoring ; Muscle, Skeletal/*physiology ; Spinal Cord/*physiology

OBJECTIVETo observe the effects of electroacupuncture on force-displacement value (FDV) of muscle state and electrophysiology of the muscle in rabbits with lumbar nerve root compression.

METHODSThirty New Zealand white rabbits were randomly divided into a control, a model, an electro-acupuncture acupoints (EAA), a medication, and an electro-acupuncture un-acupoints (EAU) group. All rabbits except those in the control group were subject to modeling (surgical lumbar nerve root compression). The control group was sham-operated without nerve root compression. The EAA group received electro-acupuncture at bilateral Shenshu (BL23) and Dachangshu (BL25) that were located 1.5 cun lateral to the posterior midline on the lower border of the spinous process of the 2nd and 4th lumbar vertebra, respectively. The EA was 15 mm deep and the frequency was 2 Hz. Each session lasted for 20 min per day for a total of 14 times. The medication group was treated with Loxoprofen sodium by gastrogavage at 4 mg/kg per day for 14 days. The EAU group received electro-acupuncture identical to the EAA group with regard to the treatment frequency and duration except a different acupoint at the tip of rabbit tail. Muscle states were determined by measuring FDVs of the bilateral biceps femoris using the Myotonometer® fast muscle state detector. Meanwhile, the prolonged and non-prolonged insertion potentials were measured by electromyography before and after modeling and after treatment. Latency, amplitude (Amp) of evoked potential, motor nerve conduction velocity (MNCV) were also determined after treatment.

RESULTS(1) After modeling, FDVs of right side activation (RSA, P=0.003) and right side relaxation (RSR) in the model group (P=0.000) were significantly decreased in comparison to the control group. The number of rabbits with non-prolonged insertion potentials in the model group was also significantly decreased (P=0.015) in comparison to the control group. (2) After treatment, FDVs of RSR were significantly increased in the EAA (P=0.000) and medication groups (P=0.018) in comparison to the model group. The increase in FDVs of RSR in the EAA group was significantly higher than that in EAU (P=0.000) and medication groups (P=0.002). MNCV in the model group was reduced compared with the control group (P=0.000). The reduction in MNCV after modeling was reversed in the EAA group (P=0.000) and medication group (P=0.008) after treatment and the increases were significant in both treatment groups in comparison to the model group. The EAA group had a greater MNCV recovery than the medication group (P=0.022).

CONCLUSIONElectro-acupuncture could improve the rehabilitation and regeneration of FDVs and the electrophysiology index of the muscle with nerve control impairment.

Animals ; Electroacupuncture ; Electromyography ; Electrophysiological Phenomena ; Evoked Potentials ; physiology ; Lumbar Vertebrae ; physiopathology ; Motor Neurons ; physiology ; Muscles ; physiopathology ; Neural Conduction ; physiology ; Rabbits ; Radiculopathy ; physiopathology ; therapy

OBJECTIVE: To find an objective and accurate examination for evaluation of spinal cord injury (SCI) in forensic clinical medicine. METHODS: The onset latency of cortex, peak latency of N1, central motor conduction time (CMCT) and wave width of the abductor pollicis brevis and the anterior tibialis were calculated by transcranial magnetic stimulation-motor evoked potential (TMS-MEP). The data of 68 patients suffered from SCI including 23 cervical levels and 45 thoracolumbar levels were collected and compared with that of 30 normal controls. RESULTS: In experimental group, when the muscle strength of the abductor pollicis brevis or the anterior tibialis decreased or disappeared, the onset latency of cortex, the peak latency of N1, and CMCT prolonged and the wave width broadened. And these indexes of grade 2 and 3 muscle strength in experimental group were higher than that in the control group (P < 0.05). CONCLUSION The TMS-MEP can determine directly and objectively the motor functional status of pyramidal tract of spinal cord in order to provide more accurate and objective evidences in forensic medicine.
Adolescent ; Adult ; Case-Control Studies ; Evoked Potentials, Motor/physiology* ; Female ; Forensic Medicine/methods* ; Humans ; Male ; Middle Aged ; Monitoring, Physiologic ; Motor Cortex/physiology* ; Muscle, Skeletal/physiology* ; Neural Conduction/physiology* ; Reaction Time/physiology* ; Spinal Cord Injuries/physiopathology* ; Transcranial Magnetic Stimulation ; Young Adult

The local field potentials (LFPs) underlying specific behavior were recorded and analyzed in this paper from primary motor cortex (M1) with several medium, such as the self-made single channel micro-electrodes, the system of multi-channels physiological signal acquisition and processing and so on. During the experiment, the specific behavior was divided into four periods according to the changes of the recorded LFPs and the changes of the specific behavior recorded simultaneously in rats. The four periods were named prophase of catching period, planning period, catching period and the completion period, respectively. Then several methods were used for the analysis of the LFPs by MATLAB, such as time domain analysis, power spectral distribution analysis and time-frequency analysis. The results suggested that the LFPs which were caused by different behavior from a large number of movement-related neurons of M1 during the specific behavior in the process of catching play an important part in the "code" guiding role in rats. The results demonstrat that the LFPs of M1 may provide a feasibility to discriminate the motor behavior of forelimb.
Animals ; Brain-Computer Interfaces ; Electrodes, Implanted ; Evoked Potentials, Motor ; physiology ; Feeding Behavior ; physiology ; Male ; Microelectrodes ; Motor Cortex ; physiology ; Rats ; Rats, Wistar

OBJECTIVETo find a way to discriminate operative reason from anaesthesia reason for the changes of intraoperative transcranial magnetic motor evoked potentials (MEPs).

METHODSIn 26 patients under Etomidate/Fentanyl anesthesia from February 2001 to June 2004, MEPs elicited by transcranial magnetic stimulation were recorded from tibialis anterior muscles, simultaneously bispectral index (BIS) and train-of-four stimulation (TOF) were used to monitor the anesthesia depth and neuromuscular blockade respectively. MEP, BIS and measurements of TOF at different anesthesia depth and muscular relaxation were recorded synchronously, statistical analysis of this data set was done in order to find the inherent relationship between these variables.

RESULTSUnder anesthesia, MEP amplitude was always positively correlated with the corresponding BIS and TOF value. A regression equation could be built, with which the MEP amplitude could be reckoned based on realtime BIS and T(1)/T(c). In case of spinal cord injury, the measured amplitude value would significantly deviate from predicted one, which suggested that the change of MEP was because of the operation, but not the anaesthesia or neuromuscular blockade. Each patient had his or her own regression equation, which was different from each other.

CONCLUSIONSThe establishment of regression equation from MEPs, BIS and TOF is very useful to distinguish reasons of the changes of transcranial magnetic MEPs during surgery, and with this technique, the intraoperative MEP monitoring should be more reliable and practicable.

Adolescent ; Adult ; Anesthesia, General ; Evoked Potentials, Motor ; physiology ; Female ; Humans ; Male ; Middle Aged ; Monitoring, Intraoperative ; methods ; Regression Analysis ; Transcranial Magnetic Stimulation ; Young Adult

OBJECTIVE: To evaluate the usefulness of monitoring transcranial electrically stimulated motor evoked potential (MEP) and its impact on postoperative motor function after surgical clipping of intracranial aneurysms. METHODS: A total of 69 aneurysm patients were monitored for MEP during surgery. The postoperative and preoperative neurological function variation and the correlation between them were compared. RESULTS: MEP deteriorated in 9/68 patients, 6 of the deteriorated MEP returned to normal within 1-40 min, and no new motor deficit emerged. 3 of MEP failed to return to the baseline, which were consistent with postoperative motor function deficit. CONCLUSION Changes in MEP could serve as early indication of the cerebral ischemia, predicting postoperative motor function and providing a guide to a safe time for temporary clipping. FNMEP monitoring is a safe and reliable tool for the integrity of facial nerve pathway in giant aneurysm surgery.
Adolescent ; Adult ; Evoked Potentials, Motor ; physiology ; Female ; Forecasting ; Humans ; Intracranial Aneurysm ; physiopathology ; surgery ; Male ; Middle Aged ; Motor Neurons ; physiology ; Neurosurgical Procedures ; instrumentation ; methods ; Postoperative Period ; Surgical Instruments ; Young Adult

OBJECTIVEThe local field potential (LFP) is a summation of dendritic potentials. The main objective of the present work is to view the features of LFP in M1 during the experimental rat pushed a paddle with the right forelimb.

METHODSFour rats were trained to press a paddle with the right forelimb for water. Then Two bundle micro-electrode with four channels were implanted into the rat's left and right primary motor cortex (M1)(AP + 3.0 mm, ML +/- 1.6 mm, H-1.6 mm) with stereotaxic apparatus. After three days recovery, 8-channel Deep-EEG and the pulse signal of paddle pressed were recorded during the rats were in operant chamber, and at the same time, the behavior were also recorded with video recorder.

RESULTSThe LFP in left M1 were defined as the substance between two channel deep-EEG. It is found that low frequency, high amplitude signal appear aligned with the paddle pressed pulse signals. With threshold detect method, about 80% press-paddle behavior could be detected.

CONCLUSIONThe result indicates that LFPs in this position in M1 are relative to forelimb's movement, and a powerful brain-computer interface system maybe developed with the LFPs.

Animals ; Brain-Computer Interfaces ; Evoked Potentials, Motor ; physiology ; Male ; Microelectrodes ; Motor Cortex ; physiology ; Movement ; physiology ; Rats ; Rats, Sprague-Dawley