Objective To investigate possible nerological origination of rabbit P3a potential. Method we simultaneously recorded the ERPs at dura and various depths beneath the skull in a point of rabbit skull, similarly did some in different points of rabbit skull. Result In the Brodmann 25 and 32 areas(AcgI), the polarity of P3a to those at dura was markedly reverse and the reverse rate of P3a(81.3%) was significantly higher than other locations, the P3a without polarity reversal showed steep voltage gradient. There was an increasing trend of the P3a reversal and moderate voltage gradient nearby the AcgI, but not other regions. Conclusion Rabbit P3a potential possibly originate from the AcgI acea.

Objective To investigate the generative and regulatory effects of AchMR on P 3a and its mechanism in different subregions of rabbit cingulate gyrus. Methods Event related potentials(ERPs) P 3a potentials in Normal, AcgI, AcgⅡand Pcg regions were recorded after microinfusion of 0.5 mmol/L scopolamine at three different time points(instantly, at the 15th minute and at the 30th minute), 2 mmol/L acetylcholine and 1 mmol/L scopolamine. Results The P 3a amplitude decreased and/or P 3a latency increased with scopolamine in time and dose dependent pattern in AcgⅠ, AcgⅡ and Pcg, and P 3a might disappear only in AcgⅠ and the P 3a again be recorded after microinfusion of acetylcholine in AcgⅠ. Conclusion The action of AchMR in AcgⅠ area markedly affects the generation and/or regulation of P 3a and confirms the AcgⅠ is the source of rabbit P 3a potential. The action of neurons in AcgⅠ might facilitate the P 3a potential.

Objective To explore a new method for evaluating muscle fatigue by analyzing the surface electromyographic(SEMG) signal characteristics and to search for the practical use of SEMG.Methods Four healthy young females performed continuous isometric contractions of vastus medialis at 65? knee extension with 60% MVC for 3 minutes. SEMG signals were recorded from bilateral vastus medialis. The data were analyzed through curve fitting and nonlinear regression.Results All the estimative curves for SEMG parameter in relation to the testing phase are of cubic with the equations of Y=b_0+b_1x+b_2x2+b_3x3. The b1 and b3 in the formula are negative and b2 is positive for MF,MPF,ZCR, whereas the b1 and b3 are positive and b2 is negative for AEMG.Conclusion The cubic curve during muscle fatigue suggests that three main factors may involve in muscle fatigue. The factors were discussed briefly and need to be confirmed further.

This paper is on effect of mobilization on immobilized ligament.Eighteen rabbits were divided into three groups.Group Ⅰ,eight weeks of active movement;group Ⅱ,eight weeks of passive+active movement;group Ⅲ,age matched normal control.The biomechanical testing,histological and ultrastructural evaluation were used.Results:with mobilization,the structural properties of ligament bone complexs of MCL obviously improved but did not return to normal.The material properties of MCL was similar to those of contralateral and normal control.Arrangement of collagen fibers was similar to that of normal.Resorption of bone in ligament bone insertion sites was not significantly changed.Through mobilization following immobilization,failure location of MCL changed.Conclusion:The recovery of material properties of ligament substance was more quick than that of structural properties of ligament bone complexs.The effect of active movement and passive +active movement on recovery of structure of immobilized ligament was similar.

ObjectiveTo study the effects of painful inter-stimulus interval on event-related potentials in rabbits for best inter-stimulus interval.MethodsElectrode was attached to F4 site on rabbits' skull. An Oddball paradigm stimulus were adopted. The waveforms recorded under different inter-stimulus interval were analysed.ResultsThe latency of pain evoked potentials P2,N2,P3a under different inter-stimulus interval showed no significant difference.The amplitude was highest when the interval was 8s.ConclusionsThere is a best inter-stimulus interval for pain evoked potential.

Objective To use event-related potentials to identify whether face recognition is implicit, and to investigate specificity, race and inversion effects in face recognition. Methods Upright and inverted photographs of Eastern and Western human faces, upright dog faces and a mobile phone were presented in random order for 150 ms to 20 healthy subjects. The subject's attention was diverted away to search for the letter ”f ” in 6 small letters below the photos. Behavioral data were recorded synchronous with event-related potentials (ERPs). Results The P100,N170 and P170 potentials were enhanced and accelerated by faces compared with non-face images. The amplitude of P100 had the strongest correlation with the type of stimulus, showing the biggest amplitude with the mobile phone image (9.5 μV ), followed by the dog face (7.5 μV ). The weakest amplitude was evoked by the human face (6.9 μV). The amplitude of N170 responded most strongly to the human face, followed by the mobile phone (0.5 μV) and the dog face ( -1.9 μV). The P170 amplitude was largest with the human face and the latency was shortest (7.8 μV and 162.2 ms), followed by the dog face (5.2 μV, 174.4 ms) and the mobile phone (5.1 μV,173.5 ms). ERP components were not affected by the orientations or races of the faces in this situation. No difference was found in the late positive component evoked by the human faces and other images. Conclusions Implicit face recognition may depend on the specifics of the stimulus, although no race effect or inversion effect was detected using this procedure.

Objective　To discuss the characteristics and mechanism of P3b potentials in rats and establish the animal model of P3b.Methods　P3b potentials and cell electric discharge in hippocampal CA1 region were recorded simultaneously inside cranio, septal and hippocampal CA1 region in rats.After septal lesions,the changes of P3b and cell electric discharge in hippocampal CA1 region were observed.Results　P3b in hippocampal CA1 region was correlated well with its cell electric discharge. Following septal lesions,P3b and cell electric discharge decreased gradually and disapeared eventually. Conclusion　Cell electric discharge in hippocampal CA1 region might be an important source of P3b.Normal structure and function of septal region were necessary to P3b's generation in hippocampal CA1 region. Additionally these suggested that cell electric discharge to target stimulation was important to P3b's generation.

Objective To observe the morphologic changes of dorsal root ganglion in the lumbar region of rabbits after the nerve root was under chronic compression and inflammatory stimulation. Methods Twenty New Zealand rabbits were recruited for this study, of which 5 served as the control (control group), and the rest were randomized into 3 experimental subgroups: 10d group, 30d group, 90d group, respectively. The autologous nucleus pulposus from the tails (about 5mg) was put into the silastic tube (inner meter of 1.5mm, external diameter 2.5mm and length 12mm), which was inserted into the left L 7 intervertebral foramen to compress the lumbar nerve root. Sham operation was performed with the rabbits in the control group. The nerve root and the dorsal root ganglia were harvested and processed and observed with light microscope and electron microscope after 10d, 30d, 90d, respectively. Results In the 10d group, obvious hyperemia, edema and infiltration of inflammatory cells in the interspace of the intima of the dorsal root ganglia (DRG) could be observed. Pyknosis, degeneration and necrosis were also found in some of the nerve cells. Electron microscopic observation showed that the number of the rough endoplasmic reticulum and mitochondrion decreased, ribosome exfoliated, mitochondrion swelled. In 30d group, typical degeneration and necrosis became more obvious. Electron microscope showed that the number of lysosome and smooth endoplasmic reticulum increased, mitochondrion swelled and its cristae disappeared, nuclei concentrated and deviated. In 90d group, significant proliferation of fibrocyte could be observed. At the same time, dura mater and arachnoid of spinal cord around the nerve root were notably thickened, and became fibrogenesis. Electron microscope also showed the increment of the lysosome and smooth endoplasmic reticulum, the swelling of mitochondrion, the loss of its cristae and the concentration of the nucleolus in the central part of the nuclei. No significant changes were found in the control group. Conclusion Pathological changes of neural degeneration such as edema, inflammatory infiltration could be observed in dorsal root ganglion after the nerve root was under chronic compression and stimulation by autologous nucleus pulposus.

BACKGROUND: Reactive depression and depressive neurosis are both psychogenic emotional disorders, clinically manifested by memory deterioration,impaired concentration, slow reaction, and bradyphrenia, among other cognitive function impairments. These subjective experiences of such patients still need to be backed up for their actual presence by objective laboratory evidences, which,however, have been scarcely available to our current knowledge.OBJECTIVE: To investigate the changes of auditory event-related Potential (AERP) P300 in patients with reactive depression and depressive neurosis, and their correlation with cognitive function impairments.DESIGN: Case-controlled experiment.SETTING: Clinical Center of Psychological Counseling, Department of Neurology, Third Military Medical University of Chinese PLA. PARTICIPANTS: Forty normal control subjects were recruited from the staff of Southwest Hospital, Third Military Medical University between September 1997 and March 1998, including 21 male and 19 female subjects aged 20-50 years. Eighty patients were selected from the agematched outpatients of the same hospital seeking psychological counseling,including 40 with reactive depression (consisting of 29 male and 11 female patients) and 40 with depressive neurosis (consisting of 24 male and 16 female patients). From these patients 10 with abnormal P300 potential were randomly selected for followed-up study, including4 with reactive depression and4 with depressive neurosis.METHODS: All the patients and normal controls were subjected to conventional examination of AERP P300 in the Laboratory of Cerebral Electrophysiology, and psychological evaluation was carried out by specialists with the assistance of Zung Self-Rating Depression Scale.MAIN OUTCOME MEASURES: ① Results of AERP P300 examination and scores of Zung Self-Rating Depression Scale in the 80 patients upon admission and 4 and 8 weeks after treatment, and results of AERP P300 examination in the control group. ② Results of AERP P300 examination and scores of Zung Self-Rating Depression Scale in the follow-up group. RESULTS: All subjects finished the study. The latency of all waves were remarkably prolonged in the patients as compared to the normal control group (P ＜ 0.05-0.01), with also lower amplitude of AERP than that of the control group; the amplitudes of N1, P2 and N2 waves, in general,tended to decrease to statistically significant levels. In reactive depression group, the amplitude of P3 wave was obviously lower than that of the control group [(10.39±4.40) vs (15.11±4.16) μV, P ＜ 0.001], and the amplitudes of all waves in the neurosis group was obviously lower than those of the control group. Comparison of the latency and amplitude of P3 in the follow-up group before and after treatment revealed no significant difference in the latency of P3 [(314.10±44.08) vs (295.4±20.74) ms, t=1.21, P ＜ 0.05], but the amplitude of P3 obviously increased after treatment to almost the normal level [(6.38±2.50) vs (14.22±2.51) μV, t=-7.012, P ＜ 0.001].CONCLUSION: Patients with reactive depression or depressive neurosis have cognitive function impairment, and auditory event-related potential P300 can be used as a reference for cognitive evaluation and therapeutic effect assessment in these patients.

Objective　 To investigate the relationships between the development of hypertrophic scar(HS) and apoptosis of fibroblast and endothelial cell, and to elucidate the influence of related modulating factors. 　Methods 　 TUNEL and immunohistochemistry staining techniques were employed to examine apoptosis of fibroblast and endothelial cell.The expression of ICE and Bcl-2 in hypertrophic scar of 61 cases of postburn patients undergoing plastic surgery with HS and in 20 other operative patients with non-hypertrophic scars(NHS)was also determined. 　Results 　 The positive apoptotic cell indices of fibroblast and vascular endothelial cells during the proliferative stage of HS were 6.60±4.43 and 8.90±6.01 respectively,while those during the mature stage were 25.60±5.70 and and 26.6±6.02, respectively.There existed evident differences in positive apoptotic cell indices between the same kind of cells (fibroblasts or vascular endothelial cells) during the two stages(P＜0.01). The ICE positive expression rate in proliferative stage was much lower than that in mature stage (P＜0.01),but the Bcl-2 positive expression rate in proliferative stage was obviously higher than that in mature stage(P＜0.01). 　Conclusion　 HS development might be related to the decrement of apoptotic fibroblasts and endothelial cells.ICE and Bcl-2 were possibly involved in the modulation of fibroblast and endothelial cell apoptosis in HS.