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.