The aim was to examine the relationship between the ability to learn new motor skills and preference to the right or left front paw when performing manipulation movements in rats. As a new skill used the Morris water maze, in which the animals are initially trained to detect platform hidden under water at the swim of the sector of the opposite platform, and then when sailing from sectors on the left or the right of the platform. Preference paw was determined by using the taking of animal food from a narrow horizontal tube and, accordingly, the rats were divided into left-handedness and right-handedness. We found that when changing the place of launch, that is the first voyage from the left or right of the sector, are right-handed, unlike left-handed, spent significantly more time to find the platform.

The aim of the present work was to study the interaction between the ability to learn a new motor skill and the preference for the right or left forelimb on performing manipulatory movements in rats. The new skill was the Morris water test, in which the animals were initially trained to find a platform hidden beneath the water by swimming from the sector opposite the platform and then by swimming from sectors located to the left and right of the platform. Forelimb preference was identified in terms of the animal’s grasping food from a narrow horizontal tube, such that the rats were divided into left-handed and right-handed animals. Our findings showed that a change in the start position for the first episodes of swimming from the left or right sector significantly increased the platform-finding time in right-handed rats, as compared with left-handed.

Результаты исследования показывают, что наличие генетической эпилепсии существенно влияет на предпочтение правой или левой конечности в процессе обучения пищедобывательному навыку у крыс. При этом такое влияние зависит от характера эпилепсии: при судорожной эпилепсии, вызываемой звуковыми стимулами, преобладает предпочтение правой конечности, т.е. доминирует активность левого полушария. В то же время при absence-эпилепсии преобладает предпочтение левой конечности, т.е. активность правого полушария. Среди крыс с судорожной эпилепсией преимущественно стволового происхождения (главным образом, крыс линии Wistar) доминируют «правши», тогда как в группе крыс линии WAG/Rij с «неконвульсивной» («absence») эпилепсией кортико-таламического генеза преобладают «левши». Предполагается, что межполушарная асимметрия при эпилепсии связана с соответствующей патологией: доминирование левого полушария («правшество») – с наличием судорожной патологии стволового генеза, а доминирование правого полушария («левшество») – с таламо-кортикальной патологией.

Xenografts from the ganglia of a newborn terrestrial snail Helix aspersa L. were implanted into the right parietal area of the brain cortex of WAG/Rij rats with absence epilepsy. Rats with implanted xenografts were trained for reaching a food ball from a tube (reaching test). It was shown that the mean duration of each leaning stage and total time necessary for acquisition of the instrumental conditioning (till the learning criterion) were shorter in animals with xenografts than in control groups of animals.

Handedness in skilled movements of animals is a result of interaction of innate motor preference and learning. The nature of the innate preference is not clear. Breeding of right-handed and left-handed mice revealed that the degree rather than direction of motor preference is an inherited feature. There is, however, a correlation between the direction of preference and a number of morphological, functional, and neurochemical characters. Shifts of a preference direction were found in some strains of mice. Differences between right-handed and left-handed rats were revealed in social behavior, learning, and resistance to forced retraining. Strains of rats with different forms of genetic epilepsy were characterized by the predominance of animals with a certain direction of the motor preference. This evidence suggests some genetic influence on a direction of the motor preference. Perhaps, genetic and environmental factors closely interact in determining motor preference in animals.

Adult Wistar rats were trained to get food from a narrow tube under conditions of free choice of a limb. After reaching a stable level of using the preferred limb, rats (n = 35) were forced to relearn the acquired skill for reaching food with a unpreferred paw. When afterwards the rats returned to the initial conditions of free choice of a limb, 12 animals (34%) did not recover their initial preference, 8 rats (23%) were ambidextrous, and 15 animals (43%) returned to the originally preferred paw. The results demonstrated different resistance of the initial limb preference to forced retraining in different animals. It is suggested that the process of retraining per se is not the only and sufficient condition of the change in "handedness". It also suggested that the different resistance of initial preference to forced retraining reflects individual differences in a degree (intensity) of this preference, which are predetermined by internal, probably by genetic factors.

Xenografts from the ganglia of a newborn terrestrial snail Helix aspersa L. were implanted into the right parietal area of the brain cortex of WAG/Rij rats with absence epilepsy. Rats with implanted xenografts were trained for reaching a food ball from a tube (reaching test). It was shown that the mean duration of each leaning stage and total time necessary for acquisition of the instrumental conditioning (till the learning criterion) were shorter in animals with xenografts than in control groups of animals.

Adult Wistar rats were trained to get food from a narrow tube under conditions of free choice of a limb. After reaching a stable level of using the preferred limb, rats (n = 35) were forced to relearn the acquired skill for reaching food with a unpreferred paw. When afterwards the rats returned to the initial conditions of free choice of a limb, 12 animals (34%) did not recover their initial preference, 8 rats (23%) were ambidextrous, and 15 animals (43%) returned to the originally preferred paw. The results demonstrated different resistance of the initial limb preference to forced retraining in different animals. It is suggested that the process of retraining per se is not the only and sufficient condition of the change in "handedness". It also suggested that the different resistance of initial preference to forced retraining reflects individual differences in a degree (intensity) of this preference, which are predetermined by internal, probably by genetic factors.

Motor asymmetry was studied in two groups of WAG/Rij rats with genetic absence epilepsy. A rat had to get food from the horizontal tube with preferable forelimb. The asymmetry coefficient Cas was calculated for the first 10, 50, and 100 trials. In the first group ("pure" absence epilepsy, n = 34) the percent of "left-handers", "right-handers", and ambidextrous calculated for the first 10 trials, was 56, 26, and 18, respectively. In the second group (mixed form of epilepsy, n = 27) this ratio was 19, 40, and 41%, respectively. The percent of ambidextrous, calculated for 50 and 100 trials, substantially decreased in both groups, and the above mentioned ratio became 62, 32, and 6% in the first group and 30, 63, and 7% in the second one. A possible association of pathogenesis of different forms of epilepsy with forelimb preference is discussed.

Motor asymmetry was studied in two groups of WAG/Rij rats with genetic absence epilepsy. A rat had to get food from the horizontal tube with preferable forelimb. The asymmetry coefficient Cas was calculated for the first 10, 50, and 100 trials. In the first group ("pure" absence epilepsy, n = 34) the percent of "left-handers", "right-handers", and ambidextrals calculated for the first 10 trials, was 56, 26, and 18, respectively. In the second group (mixed form of epilepsy, n = 27) this ratio was 19, 40, and 41%, respectively. The percent of ambidextrals, calculated for 50 and 100 trials, substantially decreased in both groups, and the above mentioned ratio became 62, 32, and 6% in the first group and 30, 63, and 7% in the second one. A possible association of pathogenesis of different forms of epilepsy with forelimb preference is discussed.