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1.
The effects of stimulation of the ipsilateral sensomotor cortex were studied on 88 neurons in the region of the main trigeminal sensory nucleus of a cat. The cortex was stimulated via a coaxial electrode by single impulses. Stimulation of the cortex caused the appearance of EPSPs and action potentials in these neurons; a small number of these responses were monosynaptic. The polarity of the impulse applied to the cortex had a significant effect on the magnitude of the latent period of the response and the postsynaptic reaction, which is apparently caused by the stimulation of different types of cortex neurons. Apparently, corticofugal pulsation regulates the level of sensitivity of the trigeminal sensory neurons.A. A. Bogomolets' Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 1, No. 1, pp. 47–53, July–August, 1969.  相似文献   

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The responses of red nucleus neurons to stimulation of the sensorimotor cortex was studied on nembutal-anesthetized cats. Most of the rubrospinal neurons were identified according to their antidromic activation. Stimulation of the sensorimotor cortex was shown to evoke in the red nucleus neurons monosynaptic excitatory potentials with a latency of 1.85 msec, polysynaptic excitatory potentials (EPSP), and inhibitory postsynaptic potentials (IPSP) with a latency of 9–24 msec. The EPSP often produced spikes. The probability of generation of spreading excitation is greater with motor cortex stimulation. The monosynaptic EPSP are assumed to arise under the influence of the impulses arriving over the corticorubral neurons as a result of excitation of axodendritic synapses. The radial type of branching of red nucleus neurons facilitates the transition from electrotonically spreading local depolarization to an action potential triggered by the initial axonal segment. Polysynaptic EPSP and IPSP seem to be a result of activation of fast pyramidal neurons whose axon collaterals are connected via interneurons with the soma of the red nucleus neurons.L. A. Orbeli Institute of Physiology of the Academy of Sciences of the Armenian SSR, Erevan. Translated from Neirofiziologiya, Vol. 3, No. 1, pp. 43–51, January–February, 1971.  相似文献   

4.
It was shown by intracellular recording that stimulation of the motor cortex evokes E PS Ps and I PS Ps in reticulospinal neurons of the gigantocellular nucleus of the cat medulla. The E PS Ps appeared in 94.3% and the I PS Ps in 5.7% of neurons tested. Analysis of the presynaptic pathway showed that 77.4% of E PS Ps studied arose through monosynaptic, and 22.6% through polysynaptic corticoreticular connections. By their latent period, duration, and rise time up to a maximum the monosynaptic E PS Ps were divided into two groups: "fast" and "slow." It is postulated that "fast" E PS Ps are generated in reticulospinal neurons which are activated by fast-conducting fibers and "slow" E PS Ps by slowly conducting corticobulbar fibers. I PS Ps were recorded from reticulospinal neurons that also were inhibited by stimulation of the ventral columns of the spinal cord. The hypothesis is put forward that cortical motor signals in cats can be transmitted to the spinal cord via monosynaptic and polysynaptic connections of "fast" and "slow" pyramidal neurons with reticulospinal neurons.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 8, No. 3, pp. 250–257, May–June, 1976.  相似文献   

5.
Unit responses of the nuclei pontis (NP) and reticular pontine nuclei (RPN) to stimulation of the frontobasal cortex (proreal, orbital, and basal temporal regions) and of the dorsal hippocampus were studied in cats. Stimulation of the various cortical structures was found to induce phasic and (less frequently) tonic responses in neurons of NP and RPN. The main type of unit response in RPN was primary excitation, whereas in NP it was primary inhibition. The largest number of responding neurons in the pontine nuclei was observed to stimulation of the proreal gyrus. In the cerebro-cerebellar relay system neurons of the reticular tegmental nucleus and ventromedial portion of NP showed the highest ability to respond. In the oral and caudal reticular pontine nuclei the regions of predominant influence of cortical structures were located in zones of these nuclei where neurons with rostral and (to a lesser degree) caudal projections were situated.M. Gorkii Donetsk Medical Institute. Translated from Neirofiziologiya, Vol. 12, No. 4, pp. 358–367, July–August, 1980.  相似文献   

6.
Field potentials and postsynaptic potentials of facial motoneurons evoked by stimulation of the caudal trigeminal nucleus were investigated in acute experiments on cats by extra- and intra-cellular recording. Pre- and postsynaptic components of field potentials were found. Four types of motoneuron response were distinguished: EPSP with generation of single action potentials; a gradual shift of depolarization inducing grouped action potentials; a rhythmic discharge of action potentials arising at a low level of depolarization; and EPSPs or EPSP-IPSP sequences. The monosynaptic and (chiefly) polysynaptic nature of these responses was demonstrated. The possible mechanism of afferent control over facial motoneurons are discussed.L. A. Orbeli Institute of Physiology, Academy of Sciences of the Armenian SSR, Erevan. Translated from Neirofiziologiya, Vol. 12, No. 3, pp. 272–282, May–June, 1980.  相似文献   

7.
We carried out intracellular recording from neurons of Clarke's column of the spinal cord of a cat. It is demonstrated that relay neurons of the dorsal spino-cerebellar tract — which are activated by proprioceptive fibers from one muscle only — are not subject to corticofugal postsynaptic control, in contrast to neurons on which excitory and inhibitory influences converge from various groups of afferents. The corticofugal effects in such neurons coincide in direction with effects evoked by flexor reflex afferents. Properties are described of neurons that are situated in the vicinity of Clarke's column but are not relay neurons of the DSCT. The hypothesis is expressed that these neurons are identical to the "border cells" — short-axon interneurons on which axonic collaterals of relay neurons terminate.A. A. Bogomolets' Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 1, No. 1, pp. 15–24, July–August, 1969.  相似文献   

8.
Responses of the neurons of the lateral and ventromedial hypothalamic regions (HL andHvm, respectively), as well as of the area of the dorsal hypothalamus (aHd) and the projection region of the medial forelimb bundle (MFB), evoked by stimulation of the proreal cortex (field 8), cingular cortex (field 24), pyriform lobula (periamigdalar cortex), and hippocampus (CA3) were studied in acute experiments on cats under ketamine anesthesia. Distributions of the latent periods of the responses recorded from hypothalamic neurons at stimulation of the above cortical structures were analyzed. The responses were classified into primary excitatory and primary inhibitory. Stimulation of the proreal gyrus evoked four times more excitatory responses than inhibitory responses. With stimulation of the cingular gyrus, the ratio of excitatory/inhibitory responses was 1.5∶1. Stimulation of the pyriform cortex evoked activatory and inhibitory responses with a similar probability. With hippocampal stimulation, inhibitory responses appeared two times more frequently than excitatory reactions. The hypothalamus was found to be a zone of wide convergence: one-half of all responding neurons in theHL andHvm responded to stimulations of two or more tested cortical zones. In 26% of the cells, only excitatory convergence was observed, while in 10% only inhibitory convergence was found; 21% of the cells revealed mixed convergence.  相似文献   

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Neuronal responses to stimulation of vestibular motor and orbital cerebral cortex were recorded by extracellular techniques in the lateral and medial vestibular nuclei of the bulbar complex during experiments on unanesthetized, immobilized cats. Both phasic and (mostly) tonic response of predominantly inhibitory type were observed. Horseradish peroxidase was injected into the aforementioned nuclei of the vestibular complex during the course of morphological experiments. Labeled neurons were found in the anterior supra- and ectosylvian cerebral gyri, the region of the cruciform sulcus, and that of the orbital cerebral cortex. Findings are discussed from the aspect of corticovestibular interaction.Ivano-Frankovsk Medical Institute, Soviet Ministry of Health. Translated from Neirofiziologiya, Vol. 19, No. 6, pp. 802–809, November–December, 1987.  相似文献   

11.
Galvanic vestibular stimulation (GVS) is a research tool used to activate the vestibular system in human subjects. When a low-intensity stimulus (1-4 mA) is delivered percutaneously to the vestibular nerve, a transient electromyographic response is observed a short time later in lower limb muscles. Typically, galvanically evoked responses are present when the test muscle is actively engaged in controlling standing balance. However, there is evidence to suggest that GVS may be able to modulate the activity of lower limb muscles when subjects are not in a free-standing situation. The purpose of this review is to examine 2 studies from our laboratory that examined the effects of GVS on the lower limb motoneuron pool. For instance, a monopolar monaural galvanic stimulus modified the amplitude of the ipsilateral soleus H-reflex. Furthermore, bipolar binaural GVS significantly altered the onset of activation and the initial firing frequency of gastrocnemius motor units. The following paper examines the effects of GVS on muscles that are not being used to maintain balance. We propose that GVS is modulating motor output by influencing the activity of presynaptic inhibitory mechanisms that act on the motoneuron pool.  相似文献   

12.
Composite and unitary EPSPs of red nucleus neurons evoked by stimulation of the sensomotor and association parietal cortex and nucleus interpositus of the cerebellum were studied in acute experiments on cats anesthetized with pentobarbital. A monosynaptic connection was shown to exist between not only the sensomotor, but also the association cortex, and rubrospinal neurons, in which unitary EPSPs appeared during stimulation of the association cortex after a latent period of 1.5–2.7 msec, with a peak rise time of 1.1–3.1 msec and an amplitude of 0.22–0.65 mV. Analysis of the temporal characteristics of the unitary EPSP suggested that synapses formed by fibers from the association cortex occupy a position nearer the soma than synapses formed by axons of sensomotor cortical cells.L. A. Orbeli Institute of Physiology, Academy of Sciences of the Armenian SSR, Erevan. Translated from Neirofiziologiya, Vol. 16, No. 1, pp. 67–74, January–February, 1984.  相似文献   

13.
Intracellular recording was employed in experiments on rats with the nervous system intact and after acute pyramidotomy to study the postsynaptic effects produced in the lumbar motoneurons on stimulation of the nucleus ruber. Stimulation of this nucleus with single stimuli and with a short series of stimuli caused excitatory and inhibitory postsynaptic potentials (EPSP and IPSP) to develop in the motoneurons. Most of the EPSP recorded were disynaptic, but response development involved a monosynaptic segmental delay in five of the 124 cells that exhibited EPSP. A capacity for high-frequency potentiation was a characteristic feature of the disynaptic excitatory and inhibitory effects. Transmembrane polarization of the motoneurons had a marked influence on the amplitude of the disynaptic EPSP and IPSP. The properties of the disynaptic rubrospinal influences were similar to those described for the cat.I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 3, No. 3, pp. 266–273, May–June, 1971.  相似文献   

14.
Experiments on cats using extra- and intracellular recording methods showed that stimulation of the motor cortex of both hemispheres leads to considerable modulation of responses to stimulation of cutaneous and muscular lower limb afferents in spinal ventral horn interneurons in segments L6, 7. Three types of conditioning corticofugal effect were observed: facilitation, inhibition, and facilitation followed by inhibition (biphasic effect), and inhibitory effects predominated. The duration of facilitation of responses did not exceed 30–40 msec. The characteristics of the time course of inhibition varied: in some cases it began with relatively short intervals (8–15 msec), in other cases with an interval of 30–40 msec; its duration was 125–500 msec, or sometimes more. The effect of cortical stimulation on responses to stimulation of various afferent inputs of the same interneuron was shown to differ. The character of the conditioning corticofugal effect correlated with the latent period of segmental responses: facilitation was observed only in responses with a relatively short latent period (under 5 msec); responses with a longer latent period were mainly inhibited. The type of cortical effect also depended on the function performed by the activated afferent input. It is suggested that differential descending control of segmental polysynaptic responses recorded in ventral horn interneurons with wide convergence of afferent influences takes place in the initial stages of the reflex are. The mechanism of this control is discussed.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neiorofizologiya, Vol. 14, No. 6, pp. 563–571, November–December, 1982.  相似文献   

15.
Stimulation of the supratrigeminal area (STA) of the rat induced a monosynaptic EPSP in most mylohyoid-digastric motoneurons and a monosynaptic IPSP or EPSP in the majority of masseteric ones, contralaterally. Stimulation of the central amygdaloid nucleus induced the ipsilateral STA activity immediately followed by the contralateral mylohyoid nerve activities. The same amygdaloid stimulated excited 19 of 46 STA neurons, which were antidromically identified to project to the contralateral trigeminal motor nucleus. Nine of these were monosynaptically excited. The mean of the antidromic and monosynaptic latencies of these neurons explains the mean onset latencies of the amygdaloid influences on the contralateral trigeminal motoneurons. Therefore, the shortest crossing amygdalo-motoneuronal pathway is probably disynaptic and mediated by commissural STA neurons.  相似文献   

16.
Synaptic responses of 121 identified cervical motoneurons to stimulation of the pyramidal tract and red nucleus were investigated by intracellular recording in cats. Responses of EPSP or EPSP-IPSP type were predominant in motoneurons of distal groups of muscles and proximal flexors, while responses of IPSP type were predominant in motoneurons of the proximal extensors. The minimal effective number of stimuli for most motoneurons was 2 or 3. The mean latent period, counted from the first stimulus in the series, was 7.86 msec for EPSPs for stimulation of the pyramidal tract and 7.91 msec for stimulation of the red nucleus, while the corresponding periods for IPSPs were 8.68 and 8.75 msec. The segmental delay of 1.3–2 msec for EPSPs and IPSPs generated in certain motoneurons in response to stimulation of both structures indicates that the shortest pathway for transmission of activity from the fibers of these tracts to the motoneurons may be disynaptic. At the same time, the possible presence of an additional neuron for most inhibitory pathways cannot be ruled out. Analysis of the results also suggests the presence of a common interneuronal apparatus for both systems.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol.3, No.6, pp. 599–608, November–December, 1971.  相似文献   

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Postsynaptic potentials evoked in accessory nerve motoneurons by stimulation of the ipsilateral and contralateral red nuclei were investigated in acute experiments on cats anesthetized with chloralose and pentobarbital. Polysynaptic EPSPs with latent periods of 5.2 to 16 (mean 9.1 ± 0.7) msec and from 5.5 to 18 (mean 10.3 ± 0.9) msec, respectively, appeared in motoneurons of the accessory nerve in response to stimulation of the contralateral and ipsilateral red nuclei. A minimum of two or three stimuli was necessary to produce EPSPs in these motoneurons. In response to single stimulation of the contralateral and ipsilateral red nuclei EPSPs appeared in four motoneurons of the trapezius muscle with latent periods of 2.5 to 5.0 and 3.0 to 5.2 msec, respectively. An increase in the number of stimuli led to action potential generation by motoneurons. The functional role of such activation is discussed.A. A. Bogomolets Institue of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 14, No. 5, pp. 532–536, September–October, 1982.  相似文献   

19.
Monosynaptic effects evoked by electrical stimulation of suprasegmental structures and the ventral and lateral columns were recorded intracellularly from motoneurons of the lumbar and cervical enlargements after isolation of the spinal cord and medulla in frogs. Reticulospinal fibers arising from cells of the medial reticular formation of the medulla and running in the ventro-lateral columns evoke monosynaptic excitation of cervical and lumbar motoneurons. The reticulo-motoneuronal E PSPs do not exceed 2–3 mV in amplitude and do not reach the threshold for action potential generation. Division of the spinal cord and interaction between all synaptic inputs tested in chronic experiments showed that monosynaptic E PSPs evoked by direct stimulation of the ventral and lateral columns are due to activation of the descending system of propriospinal fibers. By transmembrane polarization experiments the equilibrium potentials of the reticulo-motoneuronal and propriospinal monosynaptic E PSPs could be determined.I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Leningrad. Translated from Neirofiziologiya, Vol. 5, No. 2, pp. 164–173, March–April, 1973.  相似文献   

20.
Ultrastructure of the rat mesencephalic trigeminal nucleus.   总被引:1,自引:0,他引:1  
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