[The spatial organization of bioelectrical activity during the treatment of the chronic pain syndrome]. / Prostranstvennaia organizatsiia bioélektricheskoi aktivnosti v protsesse lecheniia khronicheskogo bplevogo sindroma.

EEG studies with spectral-coherent analysis and evoked potentials recording were carried out in 35 patients with deafferentation pain syndrome before and after pain-relief surgery (DREZ operations). In the cases with a significant anti-pain effect obtained there was an increase of the mean coherence level accompanied by an increase of different frequencies rhythms correlation in symmetrical regions of both hemispheres together with a marked decrease of intrahemispheric connections, especially in the frontal-temporal areas in the theta-range. After the pain-relief surgery the late positive component of somatosensory evoked potential (P220-300) decreased and visual evoked potentials became more clearly detected. Electrophysiological results give evidence on the alterations in the nonspecific afferent system after the pain-relief surgery and weakening of emotional tension. The data may be used as an objective criterion for evaluation of efficiency of surgical interventions in patients with pain.

[The neuronal reactions of the reticular nucleus of the human thalamus to verbal and sensory stimuli of differing signal strengths]. / Reaktsii neironov retikuliarnogo iadra talamusa mozga cheloveka pri rechevykh i sensornykh vozdeistviiakh razlichnoi signal'noi znachimosti.

Responses of 340 single units of the n. Rt of the human thalamus to significant and insignificant verbal and sensory stimuli during the performance of voluntary motor acts recorded by microelectrodes were investigated in dyskinetic patients in the course of 46 stereotaxic operations. Two types of polymodal units with irregular continuous (A-type, "triggered verbal command" units, 183 neurons, 56% reacting) and burst rhythmic (2-5 per s.) discharges (B-type, 139 neurons, 59% reacting) have revealed reactivity to a verbal command with a specialized multicomponent pattern at functionally different stages of purposive motor acts. The analysis of principal components has shown that the extracted components of responses correlated with the functional significance of verbal or sensory signals, especially with voluntary acts of the verbal message triggering, but not with physical, somatotopic or semantic parameters of stimulation. It was suggested that the transient time-connectivity of A and B neurons at the trigger stages of purposive tasks reflected the coexistence in the Rt of two functionally different cellular subsystems participating in the transmission of significant signals during speech-provoked voluntary acts.

[The dynamic neuronal interactions in the reticular nucleus of the human thalamus to verbal stimuli of differing signal strengths]. / Dinamika neironnykh vzaimodeistvii v retikuliarnom iadre talamusa mozga cheloveka pri rechevykh stimulakh raznoi signal'noi znachimosti.

Dynamics of neuronal interaction in 90 ensembles of the RT including units of two types (A, B) recorded by microelectrodes was analyzed during verbal and sensory stimulation and voluntary motor acts in dyskinetic patients in the course of 38 stereotaxic operations. It was shown that high transient interneuronal cooperation in A and B units were selectively related to triggering stages of a purposive act: verbal commands presentation and movement initiation and realization. Specific character of dynamics of interneuronal cooperation determined both by the type of constituent elements and functionally different stages of voluntary acts was found. It is supposed that transient interneuronal cooperation of A and B units reflects dynamic conjugation of two functionally different cellular subsystems in the Rt which are probably connected with verbal-related processing and triggering as well as with movement-related voluntary acts.

[The microsurgical treatment of traumatic lesions of the brachial plexus]. / Mikrokhirurgicheskoe lechenie travmaticheskikh porazhenii plechevogo spleteniia.

The article deals with the results of examination and surgical treatment of 213 patients with various forms and levels of traumatic damage of the branchial plexus. Five levels of damages are suggested: I--preganglionic; II--postganglionic damage of the spinal nerves and primary trunks of the brachial plexus; III--damage of the secondary trunks in the clavicular region; IV--damage of the distal parts of the brachial plexus; V--isolated damages of the initial parts of the peripheral nerves. The authors describe surgical management by the method of differentiated neurotization with nerves arising from different segments of the spinal cords, by-passing the brachial plexus. Pathological changes in the region of the trauma, the character and level of the damage, the condition of the circulatory system, the presence or absence of pain, the applied rehabilitation therapy, the duration of the disease, the patient's age, and other factors have a marked influence on the outcome of the operation. Charts of distribution of the nerve fibres of the brachial plexus in the nerve trunks were compiled more exactly on the basis of data obtained during the operative intervention and autopsy.

[Features of thalamocortical relations in the phantom pain syndrome (electrophysiologic studies during stereotaxic surgery)]. / Osobennosti talamokortikal'nykh otnoshenii pri fantomno-bolevom sindrome (élektrofiziologicheskie issledovaniia vo vremia stereotaksicheskikh operatsii).

Corticographic effects are analysed in 14 patients with severe phantom-pain syndrome from data obtained in electric stimulation of specific sensory and nonspecific nuclear structures of the thalamus. The findings of EEG, ECoG and VP analysis reflect reorganization of the thalamo-cortical relationships in the phantom-pain syndrome in the direction of disorganization of the regulating mechanisms. Evidence of this are an increased excitability level in the thalamic nuclei and the central cortex, disorder of the regional differences of the weakly modulated alpha-rhythm, and marked changes in the amplitude and configuration of VP of the parietal and central cortical areas. Various frequencies of stimulating current were used to differentiate the specific sensory and nonspecific thalamic nuclei. It was found that for the identification of the relay sensory nucleus, stimulation with a frequency range of 1-20 Hz is most effective, in which there is local synchronization of the cortical rhythm corresponding with the duration of the stimulation. Electric stimulation with a frequency of 50 Hz and more induces reactions characteristic of nonspecific nuclei: general desynchronization of the cortical rhythm during stimulation with the development of characteristic "spindles" in the after-action.

[Stereotaxic thalamotomy in the phantom pain syndrome]. / Stereotaksicheskaia talamotomiia pri fantomno-bolevom sindrome.

The results of stereotaxic thalamotomy in 18 patients suffering from a severe phantom-pain syndrome are described. It is shown that to achieve a more stable analgetic effect and a reduced emotional background of pain perception it is expedient, parallel with the destruction of the somatotopic zones of the relay posterior ventral nucleus, which have a bearing on pains in the phantom, to also exclude the non-specific afferent systems of the thalamus, that is, the median center, bordering nucleus and oroventral part of the cushion of the optic thalamus. The effects of the electrostimulation of these structures of the thalamus are described in the process of their intraoperational physiological identification. It is shown that the combined destruction of specific and non-specific afferent structures of the optic thalamus in most cases ensures a considerable diminution or disappearance of phantom pain permitting patients to readapt themselves to normal everyday life.