In this research, we compared the visual neuron responses for LGN, A18 and PMLS of old and young cats with extracellular single-neuron recording techniques. We used firing rate vector to characterize information, and response irregularity of cells to evaluate the degeneration of visual characters. Response irregularity is characterized by means of the two coefficients of variation of firing rate vectors: Cv and Cv2. We found that there was no significant change of the response irregularity in LGN areas during the aging process from young to old cats. But in the other two areas, neurons of old cats exhibited significantly larger response irregularity than those of young cats. The result indicated that the information processing function of advanced visual cortex was impaired by aging. This result also provids a reference for the research of the other neuronal system changes during aging process.
Action Potentials ; physiology ; Aging ; physiology ; Animals ; Cats ; Neural Conduction ; Neurons ; physiology ; Visual Cortex ; physiology

Hodgkin-Huxley (HH) nerve model is a famous model which is used to describe nerve impulse propagation in nerve fibre. FitzHugh-Nagumo (FHN) model is a simplification of HH model, and Huxley equation is a special case of FHN equation. It has been shown that Huxley equation possesses the basic characteristics of nerve model. Researching on these models was often carried out in virtue of numerical techniques in the past. And, in so for as is known, an efficient and simple method which can be used to obtain analytic solutions is lacking. Yet, a qualitative analysis on Huxley equation's traveling system has been carried through in this paper. There is a bounded heteroclinic orbit having its one end in connection with a saddle point for the traveling wave system. Then a linear plane autonomous system whose singular point is a saddle point is chosen. By means of the system orbit vector's slope, and according to homogeneous balance principle, the traveling wave solutions of Huxley equation's traveling system are constructed. The method used here is called LS method.
Action Potentials ; physiology ; Brain ; physiology ; Computer Simulation ; Humans ; Models, Neurological ; Neural Conduction ; physiology ; Neurons ; physiology

The aim of the present study was to establish a minimally invasive H reflex model in mice for the benefit of the research of clinical spinal cord injury and related diseases. Minimally invasive surgery was performed in hind limb of Kunming mouse under light anesthesia. The skin was incised at the point of one-third of the distance from greater trochanter to the base of the cauda. A pair of fine copper conductors were inserted into the shallow muscle using a syringe needle. After the needles were withdrawed, the retained conductors were ligated and fixed with the tissues surrounding the sciatic nerve as the first pair of stimulating electrodes. Another pair of conductors were inserted and fixed in medial malleolus close to the tibial nerve as the second stimulating electrodes. Copper conductor was inserted passing the skin above the proximal end of the metatarsal and fixed as the recording electrode. The reference electrode was placed at the walking pad in the base of the big toe using the same method. Electromyography (EMG) was used to record M and H waves in planta pedis muscles. The stimulus was a square wave with a width of 0.2 ms and frequency of 0.3 Hz. The latency time of the M and H waves which were induced from the two pairs of stimulating electrodes was recorded. Nerve conduction velocity (NCV) was then calculated from the distance between the cathodes of the stimulating electrodes and the latency time difference of M or H waves. The result showed the achievement ratios of H reflex induction were 92.73% and 81.82% in sciatic and tibial nerves, respectively. The latency time of H wave was about 7~10 ms. Motor nerve conduction velocity (MNCV) obtained was (25.84 ± 4.70) m/s (n = 35), while sensory nerve conduction velocity (SNCV) was (31.45 ± 7.30) m/s (n = 35). The method established in the present paper is simple to practice, does slight harm to the animal, and can produce waveforms with little interference. With these advantages, the method can be applied for the study of the latency of H reflex, and it is suitable for the researches which demands good physical condition of experimental animal during H reflex study. This model can also be applied to the detection of SNCV and MNCV.
Animals ; Electromyography ; H-Reflex ; physiology ; Hindlimb ; innervation ; Mice ; Neural Conduction ; physiology ; Tibial Nerve ; physiology

Hodgkin-Huxley model is the indispensable mathematics basis for the study of neuro-electro-physiology. But so far, there is few analytic study about H-H neuron model. In this paper, the features of the classical H-H model are analyzed, and then a simplified H-H model and Nagumo equation are proposed, and their solitary wave solutions are first obtained with the homogeneous balance method. The study shows that nerve impulse may propagate with the mode of solitary wave.
Action Potentials ; physiology ; Humans ; Mathematics ; Membrane Potentials ; physiology ; Models, Neurological ; Neural Conduction ; physiology

Channels from the TRP superfamily have essential roles in a wide variety of sensory transductions, especially in mechano-sensation, such as hearing, touch and mechanical pain. TRP channels are also implicated in major channelopathies, including deafness, chronic pain, autosomal dominant polycystic kidney disease (ADPKD) and ventricular hypertrophy. As the leading candidates for mechano-sensitive channels, some TRP channels appear to be mechano-receptor, which can be activated by mechanical forces directly, such as C. elegans TRPN homolog TRP-4; whereas others may act as signal modulators, receiving and amplifying signals indirectly. This review is to introduce the function of TRPs in mechano-sensory transduction and to discuss the underlying molecular mechanisms.
Animals ; Humans ; Neural Conduction ; Sensation ; physiology ; Signal Transduction ; Transient Receptor Potential Channels ; metabolism ; physiology

OBJECTIVETo summarize 4 schools of thought in studies of meridians.

METHODSConsult literature and review the history of studies of meridians.

RESULTSThe studies of meridians in the past dozens years at home and abroad have gradually formed four main theories, namely the nerve-conduction meridian theory of neurophysiology, body fluid circulation meridian theory of the physio-biochemistry, bio-field meridian theory of biophysics, and the connective tissue structure meridian theory of the overall-gap viewpoint, which are summarized and analyzed.

Acupuncture Points ; Calcium ; metabolism ; Giant Cells ; physiology ; Humans ; Magnetics ; Meridians ; Neural Conduction ; Neurotransmitter Agents ; physiology

OBJECTIVE: To study the objectivity and reliability of needle electromyography and nerve conduction for detection of musculus extensor digitorum brevis strength, which may provide a basis for establishing a quantitative detection of muscle strength in forensic clinical study. METHODS: Forty-four healthy people were enrolled as the subjects, and during toe dorsiflexion, the following items including needle electromyography indexes, motor unit potential (MUP) amplitude, MUP count, recruitment reaction type, and nerve conduction detection indexes, compound muscle action potential (CMAP) amplitude, CMAP latent period and motor nerve conduction velocity (MNCV), were simultaneously detected under the cooperation and disguise condition. RESULTS: Under the cooperation condition, regardless of the same operator or different operators, there were good test-retest reliabilities in MUP amplitude, CMAP amplitude, CMAP latent period and MNCV, while there were normal test-retest reliabilities in MUP count and recruitment reaction type and the repeatability of the same operator was slightly better than the repeatability between different operators. Under the disguise condition, test-retest reliabilities of MUP amplitude, CMAP amplitude, CMAP latent period and MNCV were relatively high, while test-retest reliabilities of MUP count and recruitment reaction type were relatively low. CONCLUSION There are good test-retest reliabilities in MUP amplitude, CMAP amplitude, CMAP latent period and MNCV, which can be conducive to comparison between different operators and results at various times; MUP count and recruitment reaction type, which can be easily affected by subjectivity of operators and examinees, can be used to differentiate whether an examinee disguises or not. The indexes used to objectively judge muscle strength remain to be further investigated.
Electrodes, Implanted ; Electromyography ; Humans ; Muscle Strength/physiology* ; Muscle, Skeletal/innervation* ; Neural Conduction/physiology* ; Reproducibility of Results ; Toes

Assessment of peripheral nerve injury is a common task in forensic practice. As an objective assistance of inspection, electrophysiological examination is significant in the evaluation of peripheral nerve function after injury. There are currently several methods of electrophysiological examination, including I-T curve, EMG, NCV and SEP. Because electrophysiological examination can assess the injury and regeneration of peripheral nerve injury at different times, it is valuable to estimate prognosis of peripheral nerve injury in forensic medicine. Besides the electrophysiological examination, evaluation of the peripheral nerve injury needs to combine other clinical manifestations to provide an accurate appraisal.
Electrodiagnosis/methods* ; Electromyography/methods* ; Forensic Medicine ; Humans ; Neural Conduction/physiology* ; Peripheral Nerve Injuries ; Peripheral Nerves/physiopathology*

The microelectrode recordings of neuron discharge, which contain noises, are very complex and apt to be disturbed by many factors during the microelectrode-guided stereotactic operations. The varying signal-to-noise ratios are obstacles to the analysis of neural spikes. A novel method based on a combination of wavelet-based and non-linear energy operator is presented for the detection of neural spikes. The method is tested for neural signals of different patients and various SNR values. The results demonstrate its performance for successful detection and effective extraction of the waveform of neural spikes.
Action Potentials ; physiology ; Algorithms ; Humans ; Microelectrodes ; Neural Conduction ; physiology ; Neurons ; physiology ; Nonlinear Dynamics ; Signal Processing, Computer-Assisted

BACKGROUNDFew studies have focused on peripheral nerve conduction during exposure to microgravity. The -6° head-down tilt (HDT) comprises an experimental model used to simulate the space flight environment. This study investigated nerve conduction characteristics of rhesus monkeys before and after prolonged exposure to HDT.

METHODSSix rhesus monkeys (3-4 years old) were tilted backward 6° from the horizontal. Nerve conduction studies (NCSs) were performed on the median, ulnar, tibial, and fibular motor nerves. Analysis of variance with a randomized block design was conducted to compare the differences in the NCS before and 7, 21, and 42 days after the -6° HDT.

RESULTSThe proximal amplitude of the CMAP of the median nerve was significantly decreased at 21 and 42 days of HDT compared with the amplitude before HDT (4.38 ± 2.83 vs. 8.40 ± 2.66 mV, F = 4.85, P = 0.013 and 3.30 ± 2.70 vs. 8.40 ± 2.66 mV, F = 5.93, P = 0.004, respectively). The distal amplitude of the CMAP of the median nerve was significantly decreased at 7, 21, and 42 days of HDT compared with the amplitude before HDT (7.28 ± 1.27 vs. 10.25 ± 3.40 mV, F = 4.03, P = 0.039; 5.05 ± 2.01 vs. 10.25 ± 3.40 mV, F = 6.25, P = 0.04; and 3.95 ± 2.79 vs. 10.25 ± 3.40 mV, F = 7.35, P = 0.01; respectively). The proximal amplitude of the CMAP of the tibial nerve was significantly decreased at 42 days of HDT compared with the amplitude before HDT (6.14 ± 1.94 vs. 11.87 ± 3.19 mV, F = 5.02, P = 0.039).

CONCLUSIONSThis study demonstrates that the compound muscle action potential amplitudes of nerves are decreased under simulated microgravity in rhesus monkeys. Moreover, rhesus monkeys exposed to HDT might be served as an experimental model for the study of NCS under microgravity.

Action Potentials ; physiology ; Animals ; Female ; Head-Down Tilt ; physiology ; Macaca mulatta ; Male ; Neural Conduction ; physiology ; Weightlessness Simulation