Search results for "Neural Conduction"
showing 10 items of 54 documents
Changes of sensory conduction velocity and refractory periods with decreasing tissue temperature in man.
1977
Changes with temperature of maximum sensory nerve conduction velocity as well as absolute and relative refractory periods were tested in 14 human subjects. Corresponding to previously published findings maximum conduction velocity decreased with cooling following a Q10 of +1.4. The absolute and relative refractory periods were increased by cooling, the Q10 being -3.1 and -3.35 respectively. There was a tendency showing a more pronounced temperature effect at low temperatures. The Q10 and the steepness of the regressionline changed at the level of 26.9 degrees C, but were significant for the relative refractory period only.
Somatosensory evoked potentials in Arnold-Chiari malformation.
2002
Abstract Nearly all patients with repaired myelomeningoceles have an Arnold–Chiari (AC) malformation and about 20% of these patients develop clinical signs of brainstem dysfunction. The management of symptomatic AC malformation is still controversial and techniques are needed to provide an objective assessment of brainstem function. We recorded somatosensory evoked potentials (SEPs) in 52 patients aged between 8 months and 20 years (median 7.3 years) with AC malformation, to determine whether the SEPs discriminate patients with symptomatic AC malformation from those without symptoms. The subcortical far-field components P13, P14 and N18, which are generated within the brainstem, were record…
Evaluation of carpal tunnel syndrome in patients with polyneuropathy
1997
The difference between the median nerve latency to the second lumbrical muscle and the ulnar nerve latency to the second interosseous muscle (L-I DIFF) was tested in a prospective study to discriminate whether prolonged distal motor latency of the median nerve in patients with polyneuropathy (PNP) reflects an additional carpal tunnel syndrome (CTS). We investigated 92 patients (107 hands) with CTS, 30 patients (34 hands) with PNP, 22 patients (27 hands) with CTS and coexisting PNP (PNP+CTS), and 77 controls (87 hands). L-I DIFF was significantly prolonged in both the CTS and PNP+CTS patients as compared to PNP patients and controls. It proved to be the most specific test to differentiate be…
Early auditory evoked potentials: developmental aspects and validity in neuropaediatric and audiologic disorders.
1984
Auditory evoked potentials and in this context especially five waves in the first 10 ms (early auditory evoked potentials = EAEP) are a diagnostic aid in topodiagnosis of posterior fossa diseases. This is due to waves I to V which arise along the acoustic nerve and in brain stem structures such as medulla, pons and mid-brain. Besides an indication about the site of a lesion in the posterior fossa, wave V allows an objective threshold determination. The present results were gained in normal children aged 1-3 years and in children with neuropaediatric and audiologic disorders.
Sympathetic Vasomotor Response of the Radial Artery in Patients With Diabetic Foot Syndrome
2003
OBJECTIVE—Neurophysiological assessment of the peripheral autonomic system is characterized by various limitations. An alternative approach to laser Doppler and venous plethymography is the assessment of the sympathetic vasomotor response of the radial artery obtained by continuous wave Doppler sonography. Nomogram data have been established and demonstrate the temporary disappearance of diastolic flow after coughing or deep inspiration. RESEARCH DESIGN AND METHODS—We assessed the sympathetic vasomotor response in 25 patients (mean age 64 years, range 43–76) with diabetic foot syndrome. The Doppler data were correlated with nerve conduction studies of the median and peroneal nerve, the exte…
Mesenchymal stromal-cell transplants induce oligodendrocyte progenitor migration and remyelination in a chronic demyelination model.
2013
Demyelinating disorders such as leukodystrophies and multiple sclerosis are neurodegenerative diseases characterized by the progressive loss of myelin that may lead toward a chronic demyelination of the brain’s white matter, impairing normal axonal conduction velocity and ultimately causing neurodegeneration. Current treatments modifying the pathological mechanisms are capable of ameliorating the disease; however, frequently, these therapies are not sufficient to repress the progressive demyelination into a chronic condition and permanent loss of function. To this end, we analyzed the effect that bone marrow-derived mesenchymal stromal cell (BM-MSC) grafts exert in a chronically demyelinate…
Ion conductance changes associated with spike adaptation in the rapidly adapting stretch receptor of the crayfish.
1975
The time course of the repetitive impulse discharges has been investigated for two high intensities of maintained depolarizing currents, 30 nA and 50 nA, for which the receptor adaptation was complete within 70 msec. The changes in sodium and potassium conductance associated with the decline in spike activity have been analyzed at different instances of time by interrupting in successive experiments the various action potentials in the pulse trains either at the early phase by holding the potential at about -60 mV and recording the inward current (upstroke-gNa) or by evaluating the delayed outward current flowing as the result of a depolarizing voltage pulse which at the end of the action p…
Functional electrical therapy for hemiparesis alleviates disability and enhances neuroplasticity
2011
Impaired motor and sensory function is common in the upper limb in humans after cerebrovascular stroke and it often remains as a permanent disability. Functional electrical stimulation therapy is known to enhance the motor function of the paretic hand; however, the mechanism of this enhancement is not known. We studied whether neural plasticity has a role in this therapy-induced enhancement of the hand motor function in 20 hemiparetic subjects with chronic stroke (age 53 ± 6 years; 7 females and 13 males; 10 with cerebral infarction and 10 with cerebral haemorrhage; and time since incident 2.4 ± 2.0 years). These subjects were randomized to functional electrical therapy or conventional phys…
Postnatal increases in axonal conduction velocity of an identified Drosophila interneuron require fast sodium, L-type calcium and shaker potassium ch…
2019
Abstract During early postnatal life, speed up of signal propagation through many central and peripheral neurons has been associated with an increase in axon diameter or/and myelination. Especially in unmyelinated axons postnatal adjustments of axonal membrane conductances is potentially a third mechanism but solid evidence is lacking. Here, we show that axonal action potential (AP) conduction velocity in the Drosophila giant fiber (GF) interneuron, which is required for fast long-distance signal conduction through the escape circuit, is increased by 80% during the first day of adult life. Genetic manipulations indicate that this postnatal increase in AP conduction velocity in the unmyelina…
4-Aminopyridine antagonizes the inhibitory effect of pentobarbital on acetylcholine release in the heart
1980
Effects of pentobarbital on acetylcholine (ACh) release, force of contraction and nervous conduction were studied in isolated heart preparations and in cervical vagus nerves, respectively. 4-Aminopyridine and tetracaine were used as pharmacological tools to eludicate the mode of action of pentobarbital. 1. 4-Aminopyridine (10−4 M) markedly increased the overflow of ACh from the isolated chicken heart evoked by electrical stimulation (1–50 Hz, 1 ms, 40 V) of the cervical vagus nerves. This effect of 4-aminopyridine was highest at low frequencies of stimulation (+ 226% at 1 Hz) and declined with increasing frequencies to reach a minimum augmentation of 22% at 30 Hz. 2. Pentobarbital and tetra…