Motor alimentary conditioned reflexes and delayed reactions in dogs following destruction of the caudate nucleus]

The characteristics of formation and achievement of motor conditioned reactions were studied in seventeen dogs before and after the lesion of head or body of the caudate nucleus. It has been shown that the degree of higher nervous activity disturbances depends on the localization of injuries in the nucleus, and on the complexity of the tests used. The caudate nucleus exerts a modulating effect on the parameters of motor conditioned reflexes and takes a direct part in the structure of delayed reflexes. Lesion of the caudate nucleus body is attended with more serious disturbances of higher nervous activity than lesion of its head.     

Alimentary conditioned reflexes in the dog after pharmacologic activation and blockade of dopaminergic structures of the caudate nucleus

Bilateral injections of 60 mcg of amphetamine and dopamine into the head of caudate nucleus produced in dogs a manifested impairment of parameters of Pavlovian alimentary conditioned reflexes but did not influence the conditioned differential inhibition. Injections of 10 mcg of haloperidol were ineffective. The most effective were the influences on the dorsal part of the caudate nucleus head.     

Effect of furosemide on changes in the rat behavior produced by intrastriatal GABA or picrotoxin microinjections

It was shown in chronic rat experiments that multiple microinjections of furosemide into the rostral region of the neostriatum facilitated avoidance conditioning in a shuttle box and prevented from GABA-induced deviant freezing, but did not abolish the choreic hyperkinesis produced by picrotoxine (GABA-A receptors antagonist) intrastriatal microinjections. Simultaneous microinjections of furosemide and picrotoxine into the neostriatum increased differences in parameters of picrotoxine-induced hyperkinesis between rat groups capable and incapable (extinct reflex) for conditioned avoidance. These findings point to a certain correlation between the intensity of hyperkinesis, capability for acquisition and realization of avoidance conditioning, and activity of neostriatal neurotransmitter systems involved in neuronal homeostasis. The findings suggest an involvement of neostriatal GABAergic system in conditioning and organization of free locomotor behavioral acts.     

Alimentary conditioned reflex behavior in the rat following injection of 6-hydroxydopamine into the caudate nucleus and nucleus accumbens

In Wistar rats with degenerated dopaminergic terminals of the caudate and accumbens nuclei (administration of 6-hydroxydopamine, 30 mcg, bilaterally), an alimentary conditioned reflex was elaborated in a T-maze. Degeneration of the caudate nucleus terminals disturbed the elaboration, while degeneration of N. accumbens terminals did not affect the learning.     

Role of enkephalin-reactive system of the caudate nucleus in acquisition of alimentary conditioned reflex in dogs

Bilateral injections of 15 and 45 mcg of synthetic analogue of TYR-D-ALA-LEY-Enkefaline-ARG into the body of the caudate nuclei in dogs produced a manifested increase in parameters of Pavlovian alimentary conditioned reflexes. Moreover, the dose of 15 mcg of LEY-enkefaline enhanced the background salivation and prolonged food consumption. Excited dogs became calm. During analogous injections into the right lateral hypothalamus the effect diminished while injections of 15 mcg of morphine hydrochloride were ineffective. The data point to role of the enkefaline-containing system in alimentary behaviour.     

Spatial organization of the caudate nucleus in dogs

The dog caudate nucleus was studied by the Nissl, Kluver-Barrera, and Golgi methods in the usual planes of section. A complex spatial organization of the caudate nucleus was established. Radial bundles of fibers form fibrous layers through which run blood vessels and in which large neurons (long-axon reticular and large short-axon smooth-dendritic) and also two types of small cells are located. In the mesh of the fibrous layers barrel-shaped concentrations of small (17.5 µm, about 2–4%, small short-axon smooth-dendritic) and medium-sized (25 µm, about 96–98%, long-axon densely branching spinous) cells can be observed. These concentrations have the appearance of two or three layers of elongated "barrels," their axis perpendicular to the surface of the internal capsule. The stria periventricularis of the caudate nucleus and certain others of its regions are less differentiated.     

The effect of lesions of the dorsomedial thalamic nucleus on alimentary conditioned reflexes and food intake in dogs.

The experiments have been carried out on 6 dogs with type II conditioned alimentary reaction. After achieving the criterion in all animals the dorsomedial thalamic nucleus was destroyed by means of electrocoagulation. After the operation hypophagia developed with a rise in the number of intertrial responses and disinhibition of the alimentary conditioned reaction not exceeding 6 days. The obtained results confirm in part the hypothesis of Brutkowski who regarded this nucleus as belonging to a system controlling feeding behavior.     

Various neurochemical mechanisms for the production of conditioned reflexes of various biologicals modalities at the level of the caudate nucleus]

Microinjection of noradrenaline in to the head of the caudate nucleus failed to influence the latent time of the conditioned reaction of avoidance and the muscle tone, but limited the motor activity and considerably increased the value and the latent time of the food-procuring reflex. Serotonin failed to influence the latent time of the conditioned defence reflex and did not alter the motor activity of rats; however, it shortened the latent period of the conditioned motor-food reflex and markedly stimulated the food-procuring reaction. Dopamine inhibited the conditioned food and defence reflex, but markedly stimulated the spontaneous motor activity of rats. The data obtained pointed to differences in the neurochemical mechanisms realizing the conditioned reflex reactions of different biological modality at the level of the caudate nucleus of rats.     

Effect of activating the putamen on alimentary conditioned reflexes in dogs

The influence was studied of the near-threshold high- and low-frequency stimulation of the putamen on achievement of alimentary conditioned reflexes in dogs. Both low- and high-frequency activation of the examined structure significantly changes the parameters of intermediate secretion, of the salivary conditioned reflexes, without influencing unconditioned ones. Unilateral stimulation disturbs the achievement of positive and inhibitory conditioned reflexes to a greater extent than bilateral one. Difference between the effects of low- and high-frequency stimulation has been revealed.