No Abstract Available.
Electrophysiology* ; Neuroendocrine Cells*

China ; Electrophysiology ; trends ; Humans

In cross sectional fashion we recoreded the cone response in 98 adult diabetics and 20 normal controls according to the recommendation by the International Society for Clinical Electrophysiology of Vision. The photopic oscillatory potentials were extracted from the cone response by highpass filtering. The clear media and attached retina were criteria for inclusion in this study. The data were statistically analyzed expecting that this procedure may provide a feature that could have some clinical significance. The analysis of variance demonstrated that the summed amplitude of the oscillatory potentials, and second oscillatory potential amplitude were the most sensitive parameters to the diabetic retina. A timing delay in the first oscillatory potential wavelet, and a reduction in the second oscillatory potential amplitude and the summed amplitude of oscillatory potentials were the commonest abnormalities. Hence, the second oscillatory potential amplitude and the summed amplitude of oscillatory potentials may be the most valuable indicator among the photopic electroretinogram parameters representing a quantitative measure of overall retinal dysfunction.
Adult* ; Electrophysiology ; Humans ; Retina ; Retinaldehyde

Computer-Assisted Instruction(CAI) improved the possibility of individualized learning by enhancing the learning efficacy related to the apptitude, competency, speed and perceptual style of each learner. The reason that I introduced the computer in teaching and learning process is based on the assumption that individual differences can be minimized by applying CAI. This has special meaning because in the current teaching and learning system we can not consider the individual differences of learners. Considering the importance of developing individualized learning program, the course of electrophysiology and pathology of K that requires typical memorization and repetition is made as a purpose to increase the efficacy of learning and thus improve the quality of nursing curriculum.
Curriculum ; Electrophysiology ; Individuality ; Learning ; Nursing ; Pathology

Saccades are rapid eye movements that shift the line of sight between successive points of fixation. The cerebellum calibrates saccadic amplitude (dorsal vermis and fastigial nucleus) and the saccadic pulse-step match (flocculus) for optimal visuo-ocular motor behavior. Based on electrophysiology and the pharmacological inactivation studies, early activity in one fastigial nucleus could be important for accelerating the eyes at the beginning of a saccade, and the later activity in the other fastigial nucleus could be critical for stopping the eye on target, which is controlled by inhibitory projection from the dorsal vermis. The cerebellum could monitor a corollary discharge of the saccadic command and terminate the eye movement when it is calculated to be on target. The fastigial nucleus and dorsal vermis also participate in the adaptive control of saccadic accuracy.
Cerebellum ; Electrophysiology ; Eye Movements ; Saccades* ; Sleep, REM

BACKGROUND AND OBJECTIVES: In radiofrequency catheter ablation (RFCA), it is an essential point to understand the characteristics of local electrograms at arrhythmic focus. However controversy exists as whether the unipolar or bipolar electrogram is superior in detecting arrhythmic focus. SUBJECTS AND METHODS: We evaluated the characteristics of unipolar and bipolar electrograms at ventricular tachycardia (VT) origin. Electroanatomical mapping and RFCA were performed in 6 patients with idiopathic VT. 22 sites were enrolled and 6 of them were successful sites. We analyzed the relationship between surface and local electrograms in accordance with success or failure. We also analyzed the morphology of local electrograms. RESULTS: At successful sites of RFCA, point of unipolar onset (22.86+/-10.82 msec vs 5.47+/-26.31 msec, p<0.05) and maximal negative slope (16.57+/-17.46 msec vs -4.00+/-22.77 msec, p<0.05) were recorded earlier than unsuccessful sites. R wave amplitude (0.11+/-0.19 mm vs 0.64+/-0.57 mm, p<0.05) and R/S ratio (0.02+/-0.30 vs 0.18+/-0.26, p<0.05) of unipolar electrograms were smaller at successful sites. R wave duration was shorter at successful sites (6.29+/-8.49 msec vs 11.33+/-6.26 msec) but there was no statistical significance. QRS duration of bipolar electrograms was longer at successful sites (66.14+/-17.93 msec vs 49.07+/-13.11 msec, p<0.05). CONCLUSION: In electranatomical mapping for VT, point of unipolar onset and maximal negative slope could predict local activation time more precisely Unipolar electrograms showed shorter R wave duration and smaller R/S ratio at successful sites of RFCA. We can estimate the focus of VT by using these chracteristics of unipolar and bipolar electrogram.
Catheter Ablation ; Electrophysiology ; Humans ; Tachycardia, Ventricular*

Here we describe and illustrate our methods for multi-channel in vivo recording in mice, including the fabrication of the microdrive array and the surgical procedure for implanting electrodes. The multi-channel microdrive is fabricated from printed circuit board base, screws, nuts and clamping screws. Rotation of the screw drives both the nut and the attached electrodes to move forward simultaneously. Each full turn of the screw corresponds to 280 µm in depth penetration. The recording electrodes are self-made tetrodes consisting 4 wires (13 µm in diameter). The major steps of headstage fabrication include: tetrode making, microdrive construction, headstage assembling and tetrode plating. The finished headstage is suitable for multi-channel recording in freely moving rodents with the modest weight and the adjustable number of recording electrodes. Additionally, the recording site is allowed to be manipulated after implantation at any time. In the latter part of this paper, we introduce the procedure of the implant surgery to record in bilateral hippocampus in mice. Using these headstages, we simultaneously recorded population activity in bilateral CA1 in freely behaving mice.
Animals ; Electrodes, Implanted ; Electrophysiology ; instrumentation ; Hippocampus ; Mice

Electroretinography has been used clinically for more than 50 years as useful retinal function test. But there has been no uniform recording signals, since various laboratories have employed different technologies and recording condition. Therefore, in 1989, International Society for clinical Electrophysiology of Vision (ISCEV) published Standard for clinical ERG, to ensure that ERG performed simply and uniformly worldwide for clinical and research purpose. We performed this standard ERG to 100 normal subjects whose range of ages were 8-79 years old. We obtained normal values of standard 5 basic response parameter. Additionally, we studied the parameter change according to age and sex. We found significantly decreased amplitude in the b-wave with age (p<0.05), and also obtained decreased rate b-wave amplitude with age. But no relation between b-wave implicit time and change of age was noted. B-wave amplitude found to be higher in women than in men (p<0.05).
Electrophysiology ; Electroretinography* ; Female ; Humans ; Male ; Reference Values* ; Retinaldehyde

BACKGROUND: Understanding the electrophysiology of radiofrequency (RF) lesions and determining the size and shape of RF lesions is important for reducing side effects when applied to patients in a clinical setting. We compared the shape and size of RF thermocoagulation produced by straight and curved 20-gauge electrodes and considered its application in clinical settings. METHODS: The white from a fresh hen's egg was warmed to 37oC and placed in a rectangular glass container. Straight and curved 20-gauge electrodes were immersed. The transparency of the egg white and the glass container made it possible to photograph the changes in size of the RF lesions over time. We applied thermocoagulation for 60 seconds at 70, 80, and 90oC. Photographs were taken at 60 seconds. We measured the maximal size of the lesions. A two-way statistical analysis of variance was performed. RESULTS: The thermocoagulations were started at the junction of the insulated and uninsulated portion of the electrode and did not extended beyond the tip. The thermocoagulation size was 4.2 +/- 0.8 at 70oC, 6.1 +/- 2.9 at 80oC and 6.1 +/- 1.9 at 90oC using the 20-gauge, 10 mm active tip, straight electrode and 4.5 +/- 1.1 at 70oC, 7.2 +/- 1.9 at 80oC and 7.9 +/- 2.7 at 90oC using the 20-gauge, 10 mm active tip, curved electrode. There was no observable difference in the size of the lesions produced by the straight and curved electrodes. CONCLUSIONS: We found that temperature was the more important factor in determining lesion size. When the temperature setting is the same, lesions produced by straight and curved electrode of the same gauge are also same size. Therefore the choice of straight or curved electrode should be made to optimize ease of handling and ensure proper location of the electrode tip.
Egg White ; Electrocoagulation ; Electrodes* ; Electrophysiology ; Glass ; Humans ; Ovum

Spatial frequency and direction tuning to drifting sinusoidal gratings are intrinsic properties of neurons in visual cortex neurons in areas 17 and 18. To investigate the stability of these tuning properties during visual stimulation in anesthetized cats, the temporal dynamics of spatial frequency and direction tuning were analyzed in every 0.1 sec. The responses of cortical neurons (n=109) as a function of spatial frequency as well as direction at a particular velocity for 1 second were measured and plotted as a contour plot. Five parameters from this plot were extracted: optimum response, preferred direction (direction that showed the optimum response), optimum spatial frequency (spatial frequency that showed the optimum response), direction tuning width (the difference between the highest and lowest directions to which the cell was at least half as responsive as it was to its optimum direction) and spatial frequency bandwidth (the difference between the highest and lowest frequencies to which the cell was at least half as responsive as it was to its optimum frequency). Then, this contour plot was further analyzed in every 0.1 sec to investigate whether these five parameters were changed or not during the course of stimulation. These parameters were plotted along the time (0.1 sec step) and a line of fit was found. Both spatial frequency and direction tuning properties were not changed in most of the cells. This suggests that both direction and spatial frequency tuning properties are stable during drifting sinusoidal gratings' stimulation.
Animals ; Cats ; Electrophysiology ; Neurons ; Photic Stimulation ; Visual Cortex