[Galvanic vestibular stimulation in physiological and clinical studies in recent years].

Galvanic vestibular stimulation is a simple, harmless, noninvasive and low-cost research technique. In spite on a long history, it has been recently found popularity as a research tool. At present occurs of its revival as a research and diagnostic tool.

[Vestibular influences on human locomotion: results obtained using galvanic vestibular stimulation].

Locomotion is the most important mode of our movement in space. The role of the vestibular system during human locomotion is not well studied, mainly due to problems associated with its isolation stimulation. It is difficult to stimulate this system in isolation during locomotion because the real movement of the head to activate the vestibular end-organs inevitably leads to the activation of other sensory inputs.

[Mechanical stimulation of soles' support zones: non-invasive method of activation of generators of stepping movements in man].

The effects of mechanical stimulation of the soles' support zones in regimens of slow and fastwalking (75 and 120 steps per minute) were studied using the model of supportlessness (legs suspension). 20 healthy subjects participated in the study. EMG activity of hip and shin muscles was recorded.

[Neuronal control of posture and locomotion in decerebrated and spinalized animals].

We have found that the brainstem-spinal cord circuitry of decerebrated cats actively maintain the equilibrium during standing, walking and imposed mechanical perturbations similar to that observed in intact animals. The corrective hindlimb motor responses during standing included redistribution of the extensor activity ipsilateral and contralateral to perturbation. The postural corrections in walking cats were due to considerable modification of EMG pattern in the limbs as well as changing of the swing-stance phases of the step cycle and ground reaction forces depending of perturbation side.

[Serotoninergic system morphofunctional aspects in control of postural and locomotion function].

Different mediator systems including serotoninergic one can influence animal's locomotor behavior. It has been shown that the spinal cord in the absence of supraspinal control is able to induce the locomotor activity in hindlimbs and afferent system can activate this mechanism. In behavioral studies on the rats with complete transection of the spinal cord it has been demonstrated that the pharmacological blocking of serotoninergic system results in depression of motor activity mediated by activation of support reactions.

[Analysis of locomotor activity in decerebrated cats during electromagnetic and epidural electrical spinal cord stimulation].

It was shown that the epidural and the electromagnetic tonic stimulation with frequency 5 Hz applied to the lumbal as well as to the cervical region of the spinal cord enabled stepping on a moving treadmill belt in decerebrated cats. It was found that there were differences in initiation of the stepping movements during epidural and electromagnetic stimulation depending on the region of spinal cord stimulation. Stimulation at frequency of 0.

[Transcutaneous electrical stimulation of the spinal cord: non-invasive tool for activation of locomotor circuitry in human].

A new tool for locomotor circuitry activation in the non-injured human by transcutaneous electrical spinal cord stimulation (tSCS) has been described. We show that continuous tSCS over T11-T12 vertebrae at 5-40 Hz induced involuntary locomotor-like stepping movements in subjects with their legs in a gravity-independent position. The increase of frequency of tSCS from 5 to 30 Hz augmented the amplitude of evoked stepping movements.

[Novel method for activation of the locomotor circuitry in human].

We examine the possibility for activation of the involuntary locomotion of the lower limbs by spinal electromagnetic stimulation (ES). The subject laid on the left side. The legs are supported in a gravity-neutral position by special mounting that to provide horizontal rotation in the hip, knee and ankle.

[Initiation of locomotion in decerebrated cat by using of impulse magnetic field projected onto the spinal cord segments].

The motor effects induced by impulse magnetic field (IMF) applied to lumbar as well as to cervical enlargements in decerebrated cat were studied. The magnetic coil with diameter 8 cm was placed on the distance 1-2 cm over the spinal cord. Single magnetic spinal cord stimulation with intensity 0.

[Mechanisms of stepping rhythm formation during epidural spinal cord stimulation in decerebrated and spinal cord transected cats].

The mechanisms of stepping pattern formation during epidural spinal cord stimulation in decerebrated and chronically spinal cord transected cats have been investigated. The features of the stepping performance in hindlimb muscles depending on the parameters of epidural stimulation and afferent input were determined. It was shown that, at nonoptimal parameters of stimulation, stepping movements are not induced.

[Locomotion induced by epidural stimulation in decerebrate cat after spinal cord injury].

The effect of partial and complete spinal cord injury (Th7-Th8) on locomotor activity evoked by epidural electrical stimulation (L5 segment, stimulation frequency 5 Hz, current strength 80-100 microA) in decerebrate cats has been investigated. It was established that the cutting of dorsal columns did not influence substantially the locomotion. The destruction of the ventral spinal quadrant resulted in the deterioration and instability of the locomotor rhythm.

[Morphofunctional characteristic of the rat distal spinal cord after its complete experimental section with subsequent treadbun training of the animal].

Motor activity of rats has been studied after complete experimental section of spinal cord at the lower thoracic level. A treadbun training performed one day after the operation has been shown to lead to the appearance of movement of hindlimbs and to restoration of function of support of the body weight. In our opinion, the key moment in initiation of locomotor movements is stimulation of foot.

[Morpho-functional characterictic of rat lumbar spinal cord enlargement].

Topography and the distribution of synaptophysin-immunoreactive structures were studied in the rat lumbar spinal cord enlargement. Synaptophysin (synaptic vesicle marker) was found in the gray matter of all Rexed laminae around most neurons and in neuropil. Subpial synaptic contacts, that were not described previously, were found in the white matter by immunohistochemistry and their presence was confirmed by electron microscopy.

[The role of skin afferent in regulation of locomotion evoked by electrical epidural stimulation of spinal cord in decerebrated cats].

The role of hindpaw skin afferent input in the locomotor pattern formation induced by epidural spinal cord stimulation was investigated in decerebrated cats. Locomotor activity was evoked by continuous 3-5Hz stimulation of dorsal surface of L4-L5 spinal segments. Kinematic and electromyographic activity (EMG) of m.

[Significance of peripheral feedback in stepping movement generation under epideral spinal cord stimulation].

In acute experiments on decerebrated and spinalized cats, the role of peripheral afferent input from hindlimbs in stepping patterns formation under epidural spinal cord stimulation (ESCS), was investigated. The hindlimb muscles' electromyographic activity and kinematic parameters of evoked stepping were analyzed. It has been shown that epidural stimulation (20-100 microA, 5 Hz) of L4-L5 spine segments induced coordinated stepping on the treadmill belt.

[Mathematical modeling of the mechanisms of locomotory pattern formation under epidural spinal cord stimulation with consideration of peripheral feedback].

The mechanisms of nervous regulation of locomotory activity of the spinal cord and participation of afferent peripheral feedback from lower limb muscles in the formation of locomotory patterns were investigated. The set of electromyograms of lower-limb muscle groups recorded in experiments on mesencephalic cats with application of electric epidural stimulations of lumbar segments of the spinal cord is described by a nonlinear dynamic model constructed on the basis of the Van-der-Pol equation with the compelling member. The conditions of occurrence of the regime of self-oscillations were investigated depending on the parameters of external influence.

[Features of stepping pattern formation in decerebrated cats under epidural spinal cord stimulation].

The mechanisms of stepping pattern formation initiated by epidural spinal cord stimulation in decerebrated cats, were investigated. It is shown that the ability to produce the stepping pattern involve the L3-L5 segments. In flexor muscle, the formation of stepping pattern under optimal stimulation frequency (5-10 Hz) of these segments is provided by polysynaptic activity with the latency 80-110 ms.

[Characteristics of the pressure center movement under upright posture regulation].

The hypothesis was put forward that, along with the regulation of mass center projection, the system of upright posture control stabilizes the deviation of pressure center from the position of the mass center projection. The regularities in the behavior of the trajectories of pressure center and mass center projection were analysed. Experimental evidence was obtained supporting the validity of the hypothesis.

[Generators of walking movements in humans: spinal mechanisms of their activation].

The paper is focused on spinal generation of walking movements in patients afflicted with loss of supraspinal control consequent to back trauma. The author cites literature on methods of initiation of walking movements with pharmacological and proprioceptive stimulation. On his own experimental investigations with epidural electrical stimulation of the spinal marrow dorsal surface he proves existence of walking generators in the human.

[Initiation of locomotor activity in spinalized cats by epidural stimulation of the spinal cord].

An area initiating locomotor activity under conditions of the spinal cord surface stimulation (SCS) was found at the upper border of the lumbar enlargement (L4-5 spinal segments). Parameters of the SCS for activation of the spinal stepping generator (SSG) were identified. Activation of the SSG under the SCS was shown to occur because of interaction of the spinal and peripheral mechanisms.

[Diagnosis and treatment of embryonal hernia].

In 1994-1999 years in clinic 19 children with omphalocele were treated, 8 of them died. Authors proposed tactic of treatment of their own, giving preference to conservative method, what permitted to reduce mortality of children with embryonal hernia.

[Control of the human and animal locomotor activity in the absence of supraspinal effects].

In patients deprived of supraspinal effects, electrical epidural stimulation of the spinal cord's dorsal surface at the level of 2nd lumbar segment induces step-like movements accompanied by respective electromyographic activity of the leg's muscles. Triggering of the step-like movements occurs at certain parameters of the stimulation. The data obtained suggest that human spinal cord has networks of interneurons-generators of the step-like movements.