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We performed morphological analysis of the structure of rat hippocampus after ablation of the left sensorimotor cortex. Four experimental groups were formed: two control groups (intravenous and intracerebral injections of the culture medium) and two experimental groups (intravenous and intracerebral transplantation of MSC). Ten weeks after surgery, disturbed cytoarchitectonics and great number of dead neurons were found in all zones of the hippocampus in animals of the control groups. In animals receiving cell therapy, no pathological changes in the structure of the hippocampus were found: hyperchromatic neurons were absent and the cells had regular shape and closely adjoined to each other.

Dogs were trained to perform the forelimb tonic flexion in order to lift a cup with meat from a bottom of the foodwell and hold it during eating with the head bent down to the cup. It is known that conditioning of the instrumental reaction is based on reorganization of the innate head-forelimb coordination into the opposite one. In untrained dogs, the forelimb flexion is accompanied by the anticipatory lifting of the head bent down to the foodwell. The following lowering of the head leads to an extension of the flexed forelimb. Tonic forelimb flexion is possible if the head is in the up position. Simultaneous holding of the flexed forelimb and lowered head providing food reinforcement is achieved only by learning. It was shown earlier that the lesion of the motor cortex contralateral to the "working" forelimb led to a prolonged disturbance of the elaborated coordination and reappearance of the innate coordination. In the present work we studied the influence of local lesions of the projection areas in the motor cortex, such as a "working" forelimb area, bilateral representation of the neck, and the medial part of the motor cortex, on the learned instrumental feeding reaction. It was found that only the lesion of the forelimb but not neck projection led to a disturbance of the learned head-forelimb movement coordination.

The choice of a forelimb by a rat within two months after the damage of the left motor cortex (the right motor cortex remaining intact) depended on the degree of recovery of the injured forelimb. There was no such correlation when the right hemisphere was damaged. Distinctions in the course of recovery after the left- and right-hemisphere injury were most pronounced in the ambidextrous rats. Under free choice conditions within two months after the injury the "handed" rats predominantly chose the initially preferred ("damaged") forelimb, while ambidextrous rats preferred to use both forelimbs.

It was shown that unilateral lesions of the left and right sensorimotor cortex in male Wistar rats led to similar deficit in manipulatory ability to perform the reaching task. Recovery rate depended on the side of lesion, i.e., damage of the right hemisphere was compensated sooner than that of the left one. This difference was significant in ambidextrous rats while in sinistrals and dextrals it was not pronounced.

The influence of the donor's cerebrospinal fluid (CSF) on retrograde transport of horseradish peroxidase (HRP) from lumbar cord segments to neurons of the sensomotor cortex (SMC) in rats after the left SMC damage was studied. The CSF of convalescents (21 days after damage) and CSF of normal rats was shown to activate the transport of HRP to neurons of the SMC of undamaged hemisphere in the recipients (second day after damage).

The authors relate new concepts of the mechanisms of the pathogenesis and compensation of central motor disorders of organic origin, based on experimental exploits of the I.P. Pavlov Physiological Department of the Institute of Experimental Medicine. It is shown that in these mechanisms, of paramount importance is the neurochemical component determining a considerable part of the symptomatology of neurological disorders and process of disturbed functions recovery. Based on the regularities discovered and studies of the properties of the convalescents" CSF, a method of its use has been developed in order to treat residual phenomena after brain stroke or craniocerebral injury. The authors describe the results of the clinical testing of that method, demonstrating its effectiveness in the treatment of chronic neurological patients.

The motor function recovery was studied after surgical damage of the left motor cortex in albino rats in control and under double gravitation action for 20 and 40 min a day. Distance between the 1st and 5th finger was measured. The positive influence was shown on post-lesional recovery.

The effect of the CSF components of the rats who had restored motor deficiency after left unilateral removal of motor neocortex, was studied in the rats with an analogous brain lesion. The first group of animals received a thermostable fraction of the donor CSF containing active factors of the posture asymmetry (FPA). The second group of animals were given a high-molecular fraction of the donor CSF with active factors inactivating the FPA. The first group revealed a significant acceleration of compensatory processes. Only a temporary positive effect was observed in the second group. The findings can be used in neurological clinics when treating motor disorders of central genesis.

Afferent and efferent connections of the transplant, implanted in the previously damaged sensorimotor area of the mature rat cerebral cortex have been studied by means of axonal transport of horseradish peroxidase. For 5 months after transplantation neural axons of the transplant are capable to reach the caudo-putamen and thalamic structures, while connections with the spinal cord are absent. The afferent connections of the transplant are minimal and belong only to the neighbouring areas of the cortex and the caudo-putamen of the recipient brain. Presence of efferent projections to the striate and thalamic structures demonstrates specificity of the projections formed; this can be a morphological base for restoration of the functions lost after the damage of the sensorimotor area of the cortex in mature animals.

In chronic experiments on cats with unilateral ablations of the motor cortical area, recovery of motor function of the contralateral forelimb was observed in average on the 31-th day after ablation. Stimulation of M-cholinoreactive brain biosystems by galantamine in combination with simultaneous suppression of N-cholinoreactive biosystems by ganglerone, shortened the period of complete compesation up to 10 days. Suppression of M-cholinoreactive systems and simultaneous stimulation of N-cholinoreactive ones by metamisil combined with galantamine prolonged the recovery period up to several months. A conclusion is drawn of an important role of M- and N-cholinergic mechanisms in providing compensatory possibilities of the brain.

The motor function recovery was studied for 3 weeks after surgical unilateral damage of the motor cortex in albino rats. Distance between the 1st and the 5th fingers was compared in intact sham--operated, operated rats, and operated animals which were suboccipitally injected with brain extract obtained from reconvalescent donor rats with the same type of damage. The injections resulted in specific changes of the parameter measured up to the level of recovery reached by the donor animal.

Instrumental food-procuring movements were studied in cats before and after unilateral or bilateral ablation of the motor or premotor cortical area. It is shown that unilateral impairment of the motor area affects the strength and accuracy of movements of the contralateral fore-leg, whereas the ablation of the premotor area leads to a slowing down of movements and breaking of a goal-directed movement into separate components. Bilataral ablation of the motor area irreversibly abolished the instrumental reflex. The ablation of the premotor cortex destroyed the animal's reaction to the sound signal, but food-procuring movements of the fore-legs were disturbed only temporarily. The obtained data are discussed on the basis of the concept that in cats the above cortical areas play different roles in the organization of goal directed behaviour.

In 50 white rats the red nucleus synaptic organization both normal and at various time (1, 2, 3, 5, 7, 10, 14, 21, 30 and 60 days) after destruction of the cerebral cortical motor area has been studied electron microscopically. Peculiarities of the synaptic organization in the parvicellular and macrocellular parts of the red nucleus and reorganization of the synapsoarchitectonics are demonstrated after the motor cortex has been destroyed. During the first 2-3 weeks after the destruction, certain degenerative changes are mainly noted in the parvicellular area of the red nucleus. Small axonal terminals with round light synaptic vesicles are subjected to degeneration according to the dark type, they form asymmetric synapses on small, sometimes--on middle dentritic branches. On the 21-30th day, together with the degenerative changes, plastic reorganization of the red nucleus synapsoarchitectonics both in the parvicellular area and in the macrocellular areas adjoining the latter are noted. Evidently, this reorganization takes place at the expense of the cerebello-rubral fibres. The participation of the inter-posito-rubral fibres terminating in the macrocellular part of the red nucleus is definitely stated. Their large terminals form synapses on the soma and the proximal dendrites of the giant and large neurons. It is from these axonal terminals that the growth cones take their origin on the 21st day after the destruction of the motor cortex. Later (on the 30th and the 60th day) new processes and synapses appear in the parvicellular part of the red nucleus. Some dendrites undergo certain changes. Dendro-dendritic synapses and complex synaptic contacts appear.

Structural characteristics (survival, growth, connections) have been studied in the transplant of the cerebral cortex tissue in Wistar rat embryos (18-day-old), implanted into the brain of mature rats of the same line at various time after a partial lesion of the sensomotor cortex. In 3-5 months after transplantation the light microscopy methods demonstrate that spatial interconnections of the transplant and the injured brain of the recipient depend on time interval between the cerebral lesion and transplantation of the embryonal nervous tissue. Horseradish peroxidase (HP) is ionophoretically injected into the recipient's cerebral tissue away from the place of transplantation. In the transplant retrogradely labelled HP neurons are revealed. This demonstrates efferent connections of the implanted tissue with the host's brain. Presence of the anterogradely labelled nervous terminals in the transplant tissue demonstrates existence of afferent connections of the transplant with the recipient's tissue. Possible mechanisms of survival, growth and formation of connections of the transplant in the injured brain of the mature animal are discussed.

On 8 cats chronic experiments were carried out to determine (spectrofluorometrically) the content of serotonin, dopamine, and noradrenaline in the sigmoid region of the left cerebral hemisphere on the second, third, forth, fifth, eighth days after the removal of the cortex of the symmetrical region of the right hemisphere. On the second day, at the time of maximum disorders of the locomotor function, dopamine content was found to decrease; there was also a tendency to reduction of noradrenaline and serotonin. On the third, and the fifth--eighth days, at the period of the locomotor activity restoration, there was a rise of serotonin content, whereas dopamine content remained low, and noradrenaline content rose considerably. The role of biochemical changes in the motor region in the mechanisms of locomotor function restoration following symmetrical damage of the large hemisphere cortex is discussed.

The role of neurohumoral factors in the mechanisms of restoring the lost motor functions after two successive unilateral removals of the neocortex motor region, was studied. The dynamics of the restoring correlated with the posture asymmetry factor (PAF) activity in the CSF. PAF activity was reduced during the restoring by an inactivation factor (FI). Periods of restoration after the 2nd extirpation and inactivation of PAF were shorter than after the 1st one. The existence of the FI before the 2nd extirpation may account for this phenomenon.

Recipient rats with unilateral ablation of the motor cortex underwent suboccipital injection of the CSF obtained from donor rats with analogous damages of their motor cortex. The dose 150 microliter of the donor CSF was most effective rendering a considerable improvement of motor functions in the recipient rats. The data obtained suggest an essentially new technique of human brain trauma therapy using injections of donor CSF.

The authors studied the time-course of functional rearrangements of the segmental apparatus after unilateral injury of the rat motor cortex. It was found that one day after injury the postural asymmetry of the hind limbs was fixed by the lumbal region of the spinal cord. This functional state of the segmental apparatus lasted 10 days after injury in the presence of the maximal activity of postural asymmetry factor (PAF) in the CSF and increasing activity of the factor in the brain tissue. Recovery of the segmental apparatus to symmetrical function by the end of the third week following injury was accompanied by PAF inactivation.