PubMed Health⌕ Search

Biomedical subjects

M E Ioffe

Publications and source records attributed to M E Ioffe.

60 records · Page 4Linked to original sources
PubMedDate not supplied

[Reversal of "handedness" in callosotomized rats].

Effect of callosotomy on the transfer of preference of one of the forepaws in performance of instrumental reaction of reaching pieces of food from a narrow horizontal tube was studied in rats. The transfer was carried out by means of artificial impediment of food procuring with the preferred paw. There was no significant difference between intact and callosotomized rats in the rate of initial paw preference determination and in the rate of paw preference transfer. However, the degree of the paw preference transfer preservation was lower in the callosotomized rats as compared with intact ones. The role of interhemispheric inhibition in motor learning is discussed.

Animals↗
PubMedDate not supplied

[Specificity of nuclear elements of the motor region of the cortex in organizing a precise motor response].

After elaboration and consolidation of precise instrumental avoidance reflexes in dogs (lifting of a fore-leg to a 4-centimeters wide "safety zone"), a part of motor cortex in the area of moving leg was ablated. After the operation the search for "safety zone" i. e. the precision of estimating the position of the leg was irreversibly impaired, but the animal was still able to hold its extremity at the same level for a long period of time. Artifically elaborated motor coordination--antagonistic to the innate one--also showed irreversible impairment. However, in case of an extremely "drilled" reaction (5.000 pairings) the elaborated coordination persisted. Minimal amplitude of correction movements increased too (i. e. subtlety of movements decreased), but during retraining this parameter of the movement became compensated. The data obtained suggest that the specificity of central cellular elements of the cortical motor area consists in estimation of extremity position which is necessary for finding a given point in space.

Animals↗
PubMedDate not supplied

[The effect of neural transplantation on audiogenic seizures in rats of different genetic strains].

The effects of neurotransplantation on development of audiogenic seizures (AS) were studied in Krushinskiĭ-Molodkina (KM) rats genetically predisposed to AS and in Wistar rats especially selected for AS. Within 24 weeks after bilateral combined transplantation of the newborn striatum and cerebellum into the parietal cortex, the AS didn't develop in Wistar rats in 74% of tests. In control Wistar rats with cortical grafts or saline injections into the parietal cortex there were no significant changes in the AS development. In the experimental KM rats the grafting led to the 4-5-times increase in the AS latency. In 50% of rats it decreased the AS severity by 1-2. In the control KM rats these parameters didn't change. It was concluded that it was possible to suppress or decrease the AS development by the transplantation of the newborn striatal and cerebellar tissue into the cortex of rats predisposed to this kind of seizures.

Acoustic Stimulation↗
PubMedDate not supplied

[Motor cortex functions in the reorganization of postural coordinations].

A well-known function of the motor cortex (MCx) is control of the limb distal musculature, in particular, isolated finger movements during precise and fine hand movements. However, MCx has another function connected with the motor learning process, namely, a suppression of synergies and coordinations interfering with a movement being elaborated. This was shown for various limb movements. However, majority of movements is accompanied by postural adjustment as well. Two experimental models of rearrangement of an innate pattern of the postural adjustment were developed, and MCx was shown during such kind of learning to suppress the activity of structures providing the innate postural patterns. In contrast to the control of limb movements, the MCx influences were found to be bilateral for the postural pattern reorganization. It was revealed recently, however, that a possibility of recovery for the sequential MCx lesions depends on the sequence of the lesions, so, perhaps the role of MCx of different hemispheres in the compensation is different.

Animals↗