Recovery of a motor habit after lesioning of the caudate nucleus in rats with different forelimb preferences

Budilin, S.Y.; Mats, V.N.

Авторы: Budilin S.Yu, Mats V.N.
Журнал: Neuroscience and Behavioral Physiology
Том: 32
Номер: 1
Год издания: 2002
Издательство: Kluwer Academic/Plenum Publishers
Местоположение издательства: United States
Первая страница: 45
Последняя страница: 48
DOI: 10.1023/A:1012948309031
Аннотация: One manifestation of asymmetry between the hemispheres of the brain is interhemisphere asymmetry in compensatory capacities. This question has received almost no study, with the exception of a number of reports on the motor areas of the cortex [1, 4]. We elected to investigate asymmetry in the recovery of a motor habit after lesioning of the head of the caudate nucleus, a structure known to be associated with performance of this habit [5]. Studies were performed on male Wistar rats weighing 250–300 g. The motor habit (MH) consisted of a reaching response, which has been used for studies of motor preference in rats. Initially, three sunflower seeds were placed on the floor of the experimental chamber, the animals being able to reach these with no hindrance. Rats then had to extract seeds from the opening of a tube 13 mm in diameter and located outside the chamber at a height of 5 cm. The first seed was placed at the edge of the tube and the rat could reach it with its tongue. The next piece of food was pushed in or held on a needle such that the rat could reach it only with its paws. At the final stage, sees were positioned in the tube to a depth of 17 mm. Performance of the response was developed over five steps [1, 2]: the first was from placing the rat in the chamber to collection of the first seed; the second was from eating the three seeds from the floor to obtaining the seed at the end of the tube with the tongue; the third was from taking the seed with the tongue to the first collection with the paw; the fourth was the first collection by scraping to the first performance of collecting food from a depth of 17 mm into the tube; the fifth consisted of 10 collections from 17 mm. According to the hypothesis presented in [1], the first and second stages characterize the emotional state of the animal and are conveniently termed the “emotional” stages; the second to fifth stages relate to the formation of the MH and are termed the “motor” stages.” The times taken to complete all stages were measured during testing. Paw preference was identified at the fifth stage, i.e., ten collections from a depth of 17 mm. This was expressed in terms of the coefficient of asymmetry (Kas), where Kas = (R – L)/(R + L), where R is the number of collections with the right paw and L is the number with the left paw. Kas was used to divide the rats into those preferring the right or left paws (termed “left-handed” and “right-handed”); 0.4 < Kas ² 1 identified right-handed rats and –0.4 < Kas ² –1 identified right-handed rats; those with –0.4 ² Kas ² 0.4 were ambidextrous animals, which used both paws [2]. The criterion ±0.4 corresponded to seven collections of 10, and this discriminator has often been used in the literature [1, 2, 4]. The set of rats studied here consisted of 27 left-handed rats and 22 right-handed rats. Some of the rats were sacrificed during the study, such that 20 and 13 survived to the end of the study. After testing, animals were anesthetized with Kalipsol and Rometar (1.5 ml/kg of each) and electrodes were inserted into two points (L 2.5 and 3.0 mm from the bregma; A 1.5 mm from the bregma; H 5.5 mm) stereotaxically and anode currents (4 mA, 40 sec) were applied to produce electrolytic lesions to the head of the caudate nucleus(CN) contralateral to the preferred paw. The same procedure was performed in a control group (six rats), and electrodes were also inserted into the CN, though no current was passed.
Добавил в систему: Мац Валентина Николаевна

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Recovery of a motor habit after lesioning of the caudate nucleus in rats with different forelimb preferencesстатья

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