共查询到20条相似文献,搜索用时 15 毫秒
1.
People affected by the catastrophe at the Chernobyl' Nuclear Power Station (ChNPS) were subjected to a detailed clinical neurological
examination. In 328 examined individuals, sympathetic skin responses (SSR), evoked by transcutaneous stimulation of then. medianus, were recorded. These people were classified in the following groups: group I, people involved in the cleanup and repair
after the catastrophe (henceforth called cleanup workers) who were subjected to relatively short-lasting, but high-intensity
irradiation (the integral absorbed dose of 0.7–6.5 Gy) and suffered from acute radiation syndrome; group II, cleanup workers
who received lower absorbed doses, but had worked at the NPS before the catastrophe and continued later to work within the
excluded zone; group III, cleanup workers involved only in the work of 1986; group IV, foresters and woodcutters, who permanently
live and work within the contamined territories; and group V, the people not involved in the work of 1986, but who worked
for a long time within the excluded zone on rotating shifts. The latter group was subdivided into two subgroups: a, men; and
b, women. Considerable SSR modifications were typical of all these groups. The amplitude of this potential sharply dropped,
while its duration increased more than 1.5 times, on average. Both these parameters showed high individual variability, and
the phase structure of SSR was noticeably modified in a considerable share of the examined people. At the same time, the SSR
latencies showed no systematic shifts, as compared with those observed in the control group. The mean amplitudes of SSR recorded
from the palms in groups I–IV and subgroups Va and Vb reached only 54, 27, 40, 47, 27, and 46% of the values measured in the
control group, while those of SSR recorded from the soles was in groups I–IV of 22, 18, 23, and 31%. The data of neurological
examination of the persons subjected to irradiation indicated an expressed pathology in the diencephalo-limbic structures;
this pathology was manifested as an autonomic dysfunction with dominating symptoms of the injury of the sympathetic system.
It is concluded that long-lasting influence of external and internal irradiation, even at its low intensity, results in serious
impairments of the central structures providing control of autonomic functions (first of all, of the hypothalamus). These
impairments lead to the development of cardiovascular and neurotrophic disorders and represent the most important factors
that determine pathological shifts both in the autonomic and somatic reflex mechanisms. 相似文献
2.
We analyzed the temporal characteristics of short-latency auditory evoked potentials (SL AEP) in people involved in the cleanup
work after the Chemobyl’ catastrophe (hereafter, cleanup workers), who now are living within the “clean” territories or remain
within the radionuclide-contaminated area (groups 2 and 3, respectively), and in persons who were not involved in the cleanup
works but are permanently living within the contaminated zone (group 4). The latencies of the SL AEP were peaks (peak latencies,
PL) in all these groups regularly exceeded corresponding values in the control group 1. The increments were mild (several
percent) but significant for the waves II–V. The most substantial PL increments were characteristic for group 3. Analysis
of the interpeak intervals showed that an increase in the I–III interval provided the greatest contribution to modification
of the SL AEP, temporal parameters. The mechanisms of influence of the Chernobyl’ catastrophe-related factors on the brainstem
auditory structures are discussed. The data allow us to conclude that functional modifications in the above structures contribute
to the hearing change for the worse observed in the people suffering from the Chernobyl’ catastrophe; a prolonged stay within
the contaminated territories represents a considerable factor aggravating these changes. 相似文献
3.
V. V. Korobov 《Neurophysiology》1999,31(4):268-270
We studied the electroneuromyographic (ENMG) indices in aged patients with cervical vertebral syndromes. The main group of
116 patients was treated with manipulation physical therapy, while the second group of 62 patients was subjected to traditional
curative procedures. In both patient groups, modifications of the EMG pattern of the forelimb muscles, a decrease in the conduction
velocity via then. medianus, and a drop in the amplitude of M responses of themm. tenar et hypotenar were observed on the injured side. After a course of manipulation therapy, a clear trend toward normalization of the above
indices was observed in the patients with a reflex pattern of the syndrome. This trend was less intensive in the subgroup
with the root syndrome pattern. In patients treated according to the traditional schemes, positive shifts in the ENMG indices
were rather small, in spite of some improvement of their clinical state. We emphasize that electrophysiological control of
the efficacy of treatment in the cases of vertebral syndromes is extremely desirable, especially in groups of aged patients. 相似文献
4.
We studied the parameters of visual evoked potentials (VEP) recorded in humans involved in the cleanup work after the Chernobyl’
catastrophe and in persons of the control group. The VEP evoked by presentation of a reversing chessboard pattern were significantly
modified in the group of cleanup workers: in many subjects their shape was drastically changed, the mean latent periods for
P100 and N145 waves increased, and their amplitudes significantly dropped. The amplitude of the P200 component somewhat increased
in the group of cleanup workers. Possible reasons for the observed changes in the evoked electrical activity and the mechanisms
underlying the changes in the visual analyzer of the persons subjected to long-term irradiation are discussed. 相似文献
5.
G. A. Bogoutskaya 《Neurophysiology》2009,41(6):416-422
In studies on healthy volunteers, we recorded an EMG discharge from the m. soleus corresponding to the H reflex evoked by transcutaneous stimulation of the n. tibialis comm. Changes in the magnitude of this reflex related to realization of brief voluntary movements of the ipsilateral upper limb
were examined. The subjects were in a prone position. Fast flexion-extension of the forearm resulted first in 100- to 200-msec-long
facilitation of the H reflex begun 30–40 msec before the appearance of EMG activity in the m. biceps brachii; this feature is indicative of the central nature of this effect related to the action of motor programs initiating the forearm
movement. Facilitation of the H reflex was followed by its inhibition lasting several seconds. Within an interval corresponding
to the maximum suppression of the H response, we tested the effect of additional conditioning stimulation of the n. peroneus comm. Occlusion of the inhibitory effects indicates that the same inhibitory neurons mediate the influences from both the peroneal
input and the pathways transmitting inhibitory influences from the neuronal systems controlling upper limb muscles. Contractions
of the ipsilateral m. biceps brachii evoked by direct electrical stimulation of the latter also resulted in inhibition of the soleus H reflex, which was rather similar in its time course to the above-mentioned inhibitory effects. There was no inhibition
of the reflex after stimulations of the cutaneous receptors and n. medianus. These findings allow us to suppose that long-lasting inhibition of the H reflex induced by voluntary movements of the upper
limb results from afferent influences from the receptors of contracting muscles. Such effects can be realized via the propriospinal
pathways or long reflex arcs. 相似文献
6.
Reversibility of the respiration-deficient locuspet23 and auxotrophic locuslys2 was followed in the standard (RAD1) and UV sensitive (rad1–2) strains ofSaccharomyces cerevisiae, both after identical doses of UV radiation and at identical survival. When comparing the reversibility after the treatment
with identical doses of UV radiation a much higher reversibility of both loci in strainrad1–2 could be detected. When comparing the reversibility of the loci in question at identical survival of both strains it could
be found that the reversibility of thepet23 locus is again much higher in strainrad1–2, whereas the reversibility of thelys2 locus is roughly identical in the two strains. Thus, the function of geneRAD1 in repair processes is apparently associated with the “error-free” repair, both at low and high doses of ultraviolet radiation. 相似文献
7.
Meeseon Jeong Young-Woo Jin Kwang Hee Yang Yoon-Ok Ahn Chang-Yong Cha 《Radiation and environmental biophysics》2010,49(1):47-55
This study examines for the first time cancer incidence between radiation and non-radiation workers in nuclear power facilities
in the Republic of Korea. Radiation workers were defined as persons who were issued with a dosimeter at nuclear power facilities,
until 2005. All analyses were conducted on male workers only (in total 16,236 individuals) because of the sparseness of females.
Statistical analyses were carried out using the standardized incidence ratio (SIR), to compare the cancer risks of radiation
and non-radiation workers with those of the general population, and the χ2 trend test was used to investigate any increase in cancer rates with dose. Poisson regression was also used to estimate the
rate ratio (RR) and the excess relative risk (ERR) after considering the confounding effect due to smoking. During 1992–2005,
99 cancer cases in 63,503 person-years were observed among 8,429 radiation workers, while 104 cancer cases were observed in
48,301 person-years among 7,807 non-radiation workers. When compared with the site- and age-specific cancer rates for the
male population of Korea, the SIR for all cancers combined was 1.07 [95% confidence interval (CI) 0.87–1.30] for radiation
workers, and 0.88 (95% CI 0.72–1.06) for non-radiation workers, respectively. The RR for radiation workers compared with non-radiation
workers was 1.18 (95% CI 0.89–1.58) for all cancers combined. The SIRs for thyroid cancer were noticeably high for both radiation
and non-radiation workers, possibly due to the screening effect, but analysis of the RR showed that there was no statistically
significant difference in thyroid cancer incidence rates between the two groups. For lung cancer, radiation workers showed
a higher incidence rate as compared to non-radiation workers, with the RR being 3.48 (95% CI 1.19–11.48). A χ2 trend test showed that there was no evidence for an increase in cancer rate with increasing cumulative dose for all cancers
combined (p = 0.5108). The ERR per Sievert was estimated to be 1.69 (95% CI −2.07 to 8.21) for all cancers combined assuming a 10 years
lag time. Consequently, a significant excess of cancer incidence among radiation workers in the nuclear power industry in
Korea was not observed. Further follow-up and an expansion of the cohort are needed to overcome the lack of statistical power
in the study. 相似文献
8.
Willem Kuyk 《Bulletin of mathematical biology》1986,48(2):107-124
Drawing evidence from a variety of cardiovascular studies on the heart rate in homeothermic animals, the author establishes
the following thesis. The servocontrol (i.e. the autonomic and reflex control) by the medulla oblongata of the heart (rate)
is a negative feedback dynamic which is isomorphic (i.e. ‘diffeomorphic’) to the dyamic underlying the heat rate control in
those animals (cf. Kuyk,Bull. math. Biol.
46, 81–102, 1984). In fact, unlike in the heat rate case, the qualitative evidence supporting this thesis can not be fully complemented
by quantitative data stemming from experiments, because of a lack of pertinent experiments—which, indeed, should measuresimultaneously the heart rate state parameter and thefour control parameters at the input side of the medulla. The results of some of the existing experiments on animal preparations can nevertheless be adduced to recognize
that this dynamic can be graphed by the five-dimensional butterfly catastrophe type. The theory leads to new ways of looking
at experiments in the field and/or setting up such experiments in the future. 相似文献
9.
Using a histochemical technique, we examined distribution of the neurons containing a marker of nitric oxide synthase (NOS),
NADPH-diaphorase (NADPH-d), on frontal slices of the medulla and upper cervical spinal segments of 4-day-old rats. It was
demonstrated that NADPH-d-positive cells are present within the dorsal and ventral medullary respiratory groups. The highest
density of the labeled middle-size multipolar neurons (27.9±2.6 cells per 0.1 mm2 of the slice) was observed in the rostral part of the ventral respiratory group, within the reticular lateral paragigantocellular
nucleus. Similar NADPH-d-positive neurons were also observed in other reticular formation structures: rostroventrolateral
reticular, gigantocellular, and ventral medullary nuclei, and in the ventral part of the paramedial nucleus. There were no
labeled neurons in the lateral reticular nucleus. Single small and medium-size labeled neurons were found at all rostro-caudal
levels of thenucl. ambiguous (nuclei retrofacialis, ambiguous, andretroam-biguous). Groups of NADPH-d-positive neurons were also revealed within the dorsal respiratory group, along the whole length of thenucl. tractus solitarii (mostly in its ventrolateral parts). Single labeled neurons were also observed in thenucl. n. hypoglossi, and their groups were observed in the dorsal motor part of thenucl. n. vagus. Involvement of the structures containing NADPH-d-positive neurons in the processes related to generation of the respiratory
activity is discussed. Our neuroanatomical experiments prove that in early postnatal mammals NO is actively involved in generation
and regulation of the medullary respiratory rhythm.
Neirofiziologiya/Neurophysiology, Vol. 32, No. 2, pp. 128–136, March–April, 2000. 相似文献
10.
Janne Avela Paavo V. Komi 《European journal of applied physiology and occupational physiology》1998,78(5):403-410
It has been suggested that during repeated long-term stretch-shortening cycle (SSC) exercise the decreased neuromuscular
function may result partly from alterations in stiffness regulation. Therefore, interaction between the short latency stretch-reflex
component (M1) and muscle stiffness and their influences on muscle performance were investigated before and after long lasting SSC exercise.
The test protocol included various jumps on a sledge ergometer. The interpretation of the sensitivity of the reflex was based
on the measurements of the patellar reflexes and the M1 reflex components. The peak muscle stiffness was measured indirectly and calculated as a coefficient of the changes in the
Achilles tendon force and the muscle length. The fatigue protocol induced a marked impairment of the neuromuscular function
in maximal SSC jumps. This was demonstrated by a 14.1%–17.7% (n.s. –P < 0.001) reduction in the mean eccentric forces and a 17.3%–31.8% (n.s. –P < 0.05) reduction in the corresponding M1 area under the electromyograms. Both of these methods of assessing the short latency reflex response showed a clear deterioration
in the sensitivity of the reflex after fatigue (P < 0.05–0.001). This was also the case for the eccentric peak stiffness of the soleus muscle which declined immediately after
fatigue by 5.4% to 7.1% (n.s. –P < 0.05) depending on the jump condition. The results observed would suggest that the modulation of neural input to the muscle
was at least partly of reflex origin from the contracting muscle, and furthermore, that the reduced muscle stiffness which
accompanied the decreased reflex sensitivity could have been partly responsible for the weakened muscle performance due to
impaired utilization of elastic energy.
Accepted: 28 April 1998 相似文献
11.
DNA sensitivity in peripheral blood leukocytes of radar-facility workers daily exposed to microwave radiation and an unexposed
control subjects was investigated. The study was carried out on clinically healthy male workers employed on radar equipment
and antenna system service within a microwave field of 10 μW/cm2–20 mW/cm2 with frequency range of 1,250–1,350 MHz. The control group consisted of subjects of similar age. The evaluation of DNA damage
and sensitivity was performed using alkaline comet assay and chromatid breakage assay (bleomycin-sensitivity assay). The levels
of DNA damage in exposed subjects determined by alkaline comet assay were increased compared to control group and showed inter-individual
variations. After short exposure of cultured lymphocytes to bleomycin cells of subjects occupationally exposed to microwave
(MW) radiation responded with high numbers of chromatid breaks. Almost three times higher number of bleomycin-induced chromatid
breaks in cultured peripheral blood lymphocytes were determined in comparison with control group. The difference in break
per cell (b/c) values recorded between smokers and non-smokers was statistically significant in the exposed group. Regression analyses
showed significant positive correlation between the results obtained with two different methods. Considering the correlation
coefficients, the number of metaphase with breaks was a better predictor of the comet assay parameters compared to b/c ratio. The best correlation was found between tail moment and number of chromatid with breaks. Our results indicate that
MW radiation represents a potential DNA-damaging hazard using the alkaline comet assay and chromatid breakage assay as sensitive
biomarkers of individual cancer susceptibility. 相似文献
12.
Interrelation of lymphocyte subpopulations in peripheral blood under cervical papillomavirus infection 总被引:1,自引:0,他引:1
Spivak MYa Lakatosh VP Lazarenko LM Lyanenko LM Azarskova MV Mikhailenko OM Tkáciková L Boroda AM 《Folia microbiologica》1999,44(6):721-725
T(CD3+)-, B(CD19+)-lymphocytes and their subsets (CD4+, CD8+, CD3+, DR+, CD3− DR+) in peripheral blood of patients with CIN I, CIN II, CIN III and cancerin situ associated with HPV infection were evaluated. In peripheral blood of women with CIN II, CIN III and cancerin situ the number of T-lymphocytes which expressed CD3+ DR+ antigen decreased. In patients with CIN I, CIN III and cancerin situ the level of the CD4+ cells decreased; the level of the CD8+ cells increased. These patients had a lower CD4/CD8 ratio, the number of B cells being standard. The results may have important
implications in the prognosis and immunotherapy of HPV infection.
Presented at theInternational Conference on Recent Problems in Microbiology and Immunology, Košice (Slovakia), 13–15 October 1999. 相似文献
13.
A comparative study of mmunoreactivity with respect to c-Fos protein in the motor (zones М1 and М2), medial prefrontal (PrL and IL), and cingular (Cg1 and Cg2) cortices allowed us to find significant differences between the intensities of expression of gene c-fos in these cortical regions in control rats (group 1) and animals trained to perform catching of food globules by the forelimb
(i.e., realizing an operant food-procuring reflex, group 2). The density of distribution of Fos-immunoreactive (Fos-ir) neurons
in rats of group 2 in motor and limbic cortical zones at +2.2 to +0.2 levels rostrally from the bregma were significantly
lower than in control rats (Р < 0.05). In animals of group 2, we also found significantly greater numbers of Fos-ir neurons in the contralateral (with respect
to the active extremity) zones of the cortex at all examined levels. These changes are probably related to functional changes
in the cortex resulting from learning of motor habits in the course of training sessions for stabilization of the operant
reflex. Histochemical estimation of the NADPH-diaphorase (NADPH-d) activity in the motor and limbic cortex showed that, in
rats of both groups, the maximum number of labeled interneurons per slice in the М1 zone were observed in layers II/III, V, and VI (5.6 ± 0.4, 6.4 ± 0.5, and 14.0 ± 0.8, respectively, within 200 × 200 μm2 areas). In the limbic cortex, NADPH-d-reactive (NADPH-d-r) interneurons were also met in layers II/III, V, and VI. Cortical
NADPHd-r neurons with the Fos-ir nuclei were not found. The presence of spatial associations of the somata or processes of
NADPH-d-r neurons with intraparenchimal arterioles and microvessels was a typical feature of the distribution of NADPH-d-reactivity
in the М1 and М2 zones, as well as in Cg1, Cg2, PrL, and IL. The following succession of the density of neurovascular associations was observed: Cg1 > Cg2 > М1 > М2 > > PrL. As is supposed, NADPH-d-r neurons (i.e., cells generating NO) are involved in the control of regional blood flow in the
studied cortical regions.
Neirofiziologiya/Neurophysiology, Vol. 40, No. 4, pp. 348–358, July–August, 2008. 相似文献
14.
A new sciaenid,Johnius (Johnius) laevis, is described from northern Australia and Papua New Guinea. Amongst theJohnius (Johnius) species with no mental barbel, ctenoid body scales, and more than 10 lower gill rakers, the new species is distinguished
by the combination of the following characters: dorsal soft rays 29–34; scales above the lateral line 5–6, and below 8–10;
eye diameter 22.4–30% HL; interorbital width 24.6–29.8% HL; and body scales with weakly developed ctenii. 相似文献
15.
Activation of “silent” efferent fibers due to stimulation of the mesenteric nerve within a definite frequency range is described;
the effect is supposed to result from sensitization in reflex circles related to visceral pain.
Neirofiziologiya/Neurophysiology, Vol. 38, No. 4, pp. 368–369, July–August, 2006. 相似文献
16.
BackgroundCancer risks following radiation exposure in adulthood after Chernobyl are less studied compared to those after exposure in childhood. We aimed to evaluate cancer risk in the Lithuanian cohort of Chernobyl cleanup workers 26 years after their exposure in Chernobyl.MethodsStudy population (6707 men) was followed for cancer incidence upon return from Chernobyl till the end of 2012 by linkage procedure with the Lithuanian Cancer Registry and for migration and death – with Central Population Registry. The site-specific cancer risk in the cohort was estimated by calculating the standardised incidence ratio (SIR) with 95 % confidence interval (CI).ResultsA total of 596 cancer cases was observed in the cohort, against 584 expected (SIR 1.02; 95 % CI 0.94, 1.11). Only incidence of mouth and pharynx cancers was increased compared to the expected (SIR 1.41; 95 % CI 1.07, 1.86). Nevertheless, an increased risk of thyroid cancer was observed among cleanup workers who were younger than 30 years when entering the Chernobyl zone (SIR 2.90; 95 % CI 1.09, 7.72), whose radiation dose was above 100 milisievert (mSv) (SIR 3.13; 95 % CI 1.30, 7.52) and who had shorter duration of stay (SIR 2.30; 95 % CI 1.03, 5.13).ConclusionsOur findings are consistent with those observed in other cohorts of workers, namely, the increased risk of cancer sites related to behavioural factors. The increased risk of thyroid cancer among cleanup workers who were younger than 30 years when entering Chernobyl and whose radiation dose was above 100 mSv cannot exclude the association with the radiation exposure in Chernobyl. 相似文献
17.
Effects of zinc deficiency and pinealectomy on cellular immunity in rats infected with Toxoplasma gondii 总被引:12,自引:0,他引:12
The effects of zinc and/or melatonin deficiencies on cellular immunity were investigated in rats infected with Toxoplasma gondii. A total of 50 adult male Sprague-Dawley rats were divided into 5 groups of 10 rats each. In group I, the rats were infected
with T. gondii and fed a zinc-deficient diet; in group II, the rats were infected and their pineal gland was surgically removed. Group III
included rats that were infected, pinealectomized, and fed a zinc-deficient diet. Group IV consisted of T. gondii-infested rats that received no treatment of any kind, and group V were normal controls. After 3 wk of treatment, all rats
were sacrificed and the percentages of CD3, CD4, and CD8 lymphocytes, zinc, and melatonin levels in plasma and the percentage
of lymphocyte in blood smears were analyzed. The CD3 ratios of groups I–III were significantly lower than those of groups
IV and V (p<0.01). The CD4 lymphocytes were significantly higher in group IV than that in all other groups (p<0.05). In group IV, the CD8 lymphocytes were higher than in groups I–III (p<0.01) and those in group V were higher than for groups I and III (p<0.01). Lymphocyte incidence in group IV was higher than in the other four groups (p<0.01). The plasma zinc and plasma melatonin levels in groups I–III were significantly lower than those in the controls (p<0.01, both cases). These results suggest that zinc and/or melatonin deficiency have a negative influence on cellular immunity
in rats with toxoplasmosis. 相似文献
18.
Variations in the amplitude of H and M responses of them. soleus related to the variation in intensity of stimulation of then. tibialis comm. were evaluated in five persons with different ratios of the maximum H and maximum M response amplitudes (from 0.27 to 0.75). A decrease in amplitude of the H reflex accompanied by an increase of M response is supposed to be determined by collision of ortho- and antidromically conducted spikes in motoneuronal axons; this makes it possible to quantify the participation of various motoneuronal populations differing in activation thresholds of their axons in H reflex generation. The H response in individuals with a low ratio of the maximum H and M response amplitudes was shown to be due primarily to the involvement of high-threshold motoneurons. When the ratio between the above-mentioned maximum EMG potentials was high, all populations of motoneurons, except very low-threshold ones, participated in the H reflex generation. In all cases, only a portion of high-threshold motoneurons was involved in H activity, which contradicts the so-called size principle.Neirofiziologiya/Neurophysiology, Vol. 25, No. 6, pp. 417–420, November–December, 1993. 相似文献
19.
We studied the effect of fatigue of the mm. gastrocnemius-soleus on the H reflex elicited by transcutaneous stimulation of n. tibialis and recorded from the m. soleus; healthy 18-to 34-year-old volunteers were tested. Fatigue was evoked by long-lasting (6 to 9 min) voluntary tonic static
sole flexion of the foot (ankle extension) with a force equal to 75% of the maximum voluntary contraction (MVC). The amplitude
of H reflex significantly (P < 0.001) decreased to about 60% of the initial value immediately after the period of fatiguing effort. Within 2 to 3 min,
it relatively rapidly recovered and reached about 90% of the control, and this was followed by a period of slow recovery to
about 96–97% of the initial value 30 min after conditioning fatigue. We suppose that the initial period of suppression of
the H reflex results to a considerable extent in an increase in the intensity of presynaptic inhibition of transmission from
Ia afferents due to tonic activation of high-threshold (groups III and IV) afferent fibers induced by intensive fatigue-related
metabolic changes in the muscles. More long-lasting (tens of minutes) changes are related to slow reverse development of direct
effects of fatigue-induced biochemical shifts in the muscle.
Neirofiziologiya/Neurophysiology, Vol. 38, Nos. 5/6, pp. 426–431, September–December, 2006. 相似文献
20.
We studied changes of the H reflex recorded from the m. soleus, which were evoked by conditioning transcutaneous stimulation of the n. tibialis and n. peroneous comm. of the contralateral leg. In both cases, rather similar two-phase changes in the amplitude of the tested H reflex were observed.
After a latent period (50 to 60 msec), the reflex was facilitated for about 300 msec, with the maximum at an about 100-msec-long
interval. Then, facilitation was replaced by inhibition; the time course of the latter at test intervals longer than 500 msec
could be satisfactorily approximated by a logarithmic curve. The mean durations of inhibition calculated with the use of a
least-square technique were 4.0 and 2.7 sec in the cases of stimulation of n. tibialis and n. peroneous comm., respectively. Facilitation of the reflex was initiated with the intensity of conditioning stimulation corresponding to the
threshold for excitation of cutaneous receptors. Facilitation could also be evoked by electrical stimulation of the skin in
the contralateral popliteal dimple outside the projections of the above-mentioned nerves. Inhibition of the H reflex was evoked
only with greater intensities of transcutaneous stimulation of the contralateral nerves corresponding to activation of low-threshold
afferents of the above-mentioned nerves. The examined inhibition of the H reflex is probably of a presynaptic nature because
it was not eliminated by tonic activation of the motoneurons of the tested muscle evoked by voluntary sole flexion. Long-lasting
contralateral presynaptic inhibition can play a noticeable role in redistribution of the tone of skeletal muscles in the course
of the motor activity.
Neirofiziologiya/Neurophysiology, Vol. 37, No. 4, pp. 372–378, July–August, 2005. 相似文献