Effect of disulfiram on the interconnected activity of cortical neurons in trained cats

The action of disulfiram on interconnected activity of neurones in the visual and motor cortical areas was studied in cats with food-procuring conditioned responses to light. Multiunit activity was recorded from the areas and, by means of amplitude discrimination, separated into impulse flows. Crosscorrelation analysis of the impulse series was used to reveal the character and temporal parameters of interconnected activities of neurones firing in correlation within the limits both of the same cortical area and of the two different ones. A depressing action was shown of the disulfiram on the food-procuring reaction, accompanied by a decrease of the number of pairs of neurones from the visual and motor cortical areas mostly acting in interconnection, interactions with long time delays being mostly affected. The character of action of neighbouring neurones in the visual and motor cortical areas changed in the same direction, expressed in their firing by a "common source" type. The question is discussed of disulfiram influence on interneuronal connections of both types suggesting a decrease of alimentary motivation as well as disturbance of food-procuring conditioned motor coordination.     

Natural 1st and 2d degree conditioned food reflexes in the dog in relation to space orientation

In three dogs formation and performance of spatial alimentary natural conditioned responses of the second order was studied when the dog had to find food preliminarily shown to it in one of the four food-distributors (psychonervous activity directed by a food image in terms proposed by I. S. Beritashvili). Characteristics of this form of behaviour were demonstrated and discussed: rapid formation, dependence of performance on the delay time, conflict between responses of the first and the second order. In the second series of the experiments food-procuring behaviour of dogs was studied under conditions of conflict between the quality (value) of alimentary reinforcement and probability of its finding in certain food-distributor. Such kind of behavior was shown to depend on the motivation level and individual characteristics of the dog. Interaction of "informational" (anterior areas of the neocortex, hippocampus) and "motivational" (nuclei of amigdalar complex, hypothalamus) cerebral structures is supposed to underlie the organization of behaviour.     

Dynamics of caudate nucleus involvement in the process of internal inhibition of the food-getting reflex]

Changes of slow spindle electrical activity (12 to 14 cps) and evoked potentials in the cat caudate nuclei and the motor cortex were studied at different stages of elaboration of differentiation inhibition of a conditioned food-procuring reflex to acoustic stimuli. It has been shown that participation of the caudate nuclei in the inhibitory process begins at the stage of enhancement of food-procuring activity (second stage) and is apparently due to the animal's strong alimentary motivational excitation. At the third stage the inhibitory influence of caudate nuclei on the animal's motor activity in general, and the activity of the motor cortex in particular, develops to the full.     

Effect of alimentary deprivation on quantitative and time characteristics of nutrition of the goldfish in norm and under action of adrenalin

Effects of the intraperitoneally administered adrenalin (0.14 mg/kg) on volume and time characteristics (duration) of the individual, grouped, and summarized nutrition was studied in goldfish Carassius auratus (L.) previously kept on normal and restricted (for 10 and 15 days) ration. The fish on restricted ration demonstrated the two-phase alimentary response to the adrenalin injection similar with that in normally feeding fish: a decrease in volume and in the grouped and summarized duration of nutrition in the first phase of the hormone action and an increase-in the second phase; however, the value of the effect in the first phase was lower, while in the second phase-higher than in the fish that obtained before the experiment the sufficient amount of food. Duration of individual nutrition increased in all fish groups, including the control one, the maximal increase being observed in goldfish submitted to alimentary deprivation. The content of glycogen in hepatopancreas of the normally fed goldfish by the end of experiment exceeded that in fish restricted in nutrition 4.5–6 times. The obtained results confirm the suggestion that a decrease of level of reserved substances in the body leads to reduction of susceptibility of fish to the stress hormoneadrenalin and, hence, to a change of the value of its effects on the goldfish food-procuring activity, with preservation of dynamics of parameters.     

Effects of reorganization of the food-procuring behavior in the time deficit situation in primates

The organization of the food-procuring behavior inMacaca mulatto was studied under conditions of the time deficit. It has been shown that if the duration of performance of the alimentary behavior in the animals is restricted by 8 s, four ways of individual arrangement of their activity are observed: (1) stabilization of time intervals between the acts performed; (2) shift of the effectiveness of performance from the instrumental phase to the consumatory one of the reflex in the same animal in different experiments; (3) in the case of an individual experiment: an increased effectiveness of performance of one act (the instrumental or consumatory one) and a decreased effectiveness of the other; (4) an abrupt change in the tactics of motor responsiveness. All the behavioral phenomena revealed are believed to be connected with a voluntary and goal-oriented strive of the monkeys to obtain the maximal amount of food under the conditions of time deficit by way of the active (directly in the experiment) or latent (at the intersignal period) reorganization of their activity program. Deceased.     

Automated Food-Procuring Movement-Related Neuronal Activity in the Basolateral Amygdala of the Rat

We studied the impulse activity of neurons of the basal and lateral amygdalar nuclei generated when experimental animals (rats) performed fast stereotyped food-procuring movements by the forelimb. Within the basolateral amygdala, there are neurons whose activity is related to different stages of getting off the food, and according to the characteristics of their spiking these neurons should be divided into a number of subpopulations. Activation forestalling the movement initiation by 0.5-1.0 sec was observed in most neurons of the basolateral amygdala; this is considered a manifestation of excitation related to a motivation component of the food-procuring behavior. Activation of amygdalar neurons following movement initiation can result from generation in this structure of additional excitation necessary for successful performance of a complete food-procuring motor cycle.     

Coordination of locomotor activity of mollusc Lymnaea stagnalis at nutrition: Role of the internal medium acid-base balance (pH)

The correlation was studied between the hemolymph pH value and the locomotion rate in the mollusc Lymnaea stagnalis at different degree of activation of the food-procuring behavior. It is established that the hemolymph pH value remains unchanged in the satiated (hungry), freely moving Lymnaea individuals, and, hence, it does not determine the locomotor activity of molluscs in these functional states. In the course of food consumption, locomotion decreases significantly, which is due to an observed decrease of the hemolymph pH. This effect is realized through the corresponding changes of electrical activity of motoneurons of the locomotor network of the Lymnaea nervous system (PeA-cluster). It is suggested that the pH value plays the modulating role in coordination of activities of the nervous centers of the mollusc nutrition and locomotion.     

Neurochemical mechanisms of the inhibitory influence of the hippocampus on the conditioned food-getting reaction in rats]

A study was made of the influence of microinjections of dopamine, noradrenaline, serotonin and glutamic acid into the dorsal hippocampus on the food-procuring conditioned reaction of rats. All the examined drugs lengthen the latency of the conditioned alimentary reaction. However, the number of pushes of the door leading to the feeding through and the magnitude of the reflex are increased by catecholamines and glutamic acid, but reduced by serotonin. The dopamine effects are achieved through archicortex neurones receptors, sensitive to haloperidol, the noradrenaline effects, through alpha-adrenoreactive, and of serotonin, through M-serotoninsensitive structures of the hippocampal neuronal systems. The modulating influence of glutamic acid on the food-procuring conditioned reaction is not connected with the active on dopamine-, adreno or serotonin neuronal receptors of the rat dorsal hippocampus.     

Roles of the Caudate Nuclei, Cerebellum, and Caudato-Cerebellar Interconnections in the Control and Coordination of Ballistic Food-Procuring Movements

We studied the roles of the cerebellum and caudate nuclei in the programming and control of ballistic movements. An experimental model of operant food-procuring movements of the rats was used; the activity of single neurons of the above structures was recorded in the course of these motor performances. To evaluate the impact of the cerebellar–caudate interaction on the process of control of the ballistic (centrally programmed) components of food-procuring motor performance, we also recorded modifications of the neuronal activity in one of the above-mentioned structures induced by electrical extrastimulation of another structure in the course of realization of the above components. It is demonstrated that the cerebellum and, in particular, its dentate nuclei are involved in the programming of ballistic food-procuring movements. Neurons of the caudate nuclei play a significant role in the immediate preparation for and subsequent current control of stereotyped ballistic movements. The high plastic properties of the cerebellar neurons manifested in the process of control of ballistic food-procuring movements are proved.     

The effect of ablation of the caudate nucleus on the alimentary zone of the lateral hypothalamus]

A conditioned food-procuring reaction previously elaborated to an acoustic stimulus was reproduced in chronic experiments on six cats by means of direct electrical stimulation of the posterior parts of the lateral hypothalamus. Folloiwng extensive bilateral electrolytic ablation of the caudate nucleus, conditioned food-procuring reaction to the stimulation of the hypothalamus could not be reproduced for 40 to 70 days. The conditioned foor-procuring reflex to the acoustic stimulus disappeared for 14 to 30 days to be subsequently spontaneously restored. After caudatotomy, a diminution of the average amplitude of background oscillations and of evoked potentials to acoustic stimuli was recorced in the examined zones of the lateral hypothalamus. The part played by the caudate nucleus in the processes of alimentary behaviour activation is discussed.     

The dynamics of the interimpulse intervals in the activity of sensorimotor cortex neurons during the acquisition of the food-procuring reflex in the rabbit]

State of hunger is characterized by the presence of definite distribution of interimpulse intervals in the activity of sensorimotor cortical neurones (SMC) of rabbit. Mostly bi- and three-modal distribution of interimpulse intervals in the background activity in hungry animals changes in the process of elaboration of food-procuring habit. As the habit consolidates, the SMC neurones acquire the ability to forestalling actions. Peculiarities are revealed of organization of the SMC neurones impulse stream in response to the action of conditioned signal in the case of abolition or substitution of the reinforcement. Repeated substitutions of reinforcement cause the formation of activity of concordance in the moment of substitute "recognition" despite the absence of alimentary reinforcement.     

Neuropharmacologic analysis of the process of developing extinctive inhibition in the lobectomized cat

Pharmacological action on cholinergic and monoaminergic brain structures in the process of food-procuring reflex extinction was studied in intact and lobectomized cats. Growing stimulation of cholinergic structures of lobectomized animals caused consecutive behavioural changes similar to those appearing during development of active reaction of intact animals to cancellation of the reflex reinforcement. In both cases influences on monoaminergic systems produced analogous effects, but suppressing influence of haloperidol injection on food-procuring activity of lobectomized cats was significantly weakened. Conclusion is made that the development of active reaction of the animal to cancellation of food reinforcement is due to an increasing activation of brain cholinergic structures and consecutive activation of monoaminergic structures. Disturbance of extinction functions in lobectomized cats may be connected with disturbance of monoaminergic systems balance as a result of hyperactivity of dopaminergic structures.     

Inhibitory correction of conditioned reflex behavior in the rat at different stages of its performance

Inhibitory effect of differential signal was tested in rats at different stages of their food-procuring behaviour. Inhibitory correction of alimentary behaviour was the more effective the nearer the moment of test was to the beginning of performance of the motor program.     

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.     

Aspects of the ultrastructure of the alimentary canal and respiratory ducts in Xenopus laevis larvae

The pharynx, intestine and respiratory duct of Xenopus laevis were examined by light and electron microscopy, at different stages of the metamorphic cycle, through climax. It is well known that preclimactic larvae are suspension feeders and that after climax specimens feed on solid food. It is shown that the histology of the pharynx and the alimentary canal changes in adaptation to the change in the mode of feeding. Suspension feeding utilises ciliary activity but after climax cilia have disappeared from the pharynx and alimentary canal, when new neuromuscular mechanisms are utilised in feeding. Other morpho-histological changes in various intestinal and respiratory tissues are likewise considered in terms of functional activity.     

Activation of Neurons of the Medullary Centers of the Autonomic Nervous System Related to Motivated Operant Movements Realized by Rats

Using the corresponding techniques, we visualized Fos-immunoreactive (Fos-ir) and NADPH diaphorasereactive (NADPH-dr) neurons in the medullary centers of the autonomic nervous system (ANS) of rats, which performed repetitive operant movements (catching of food globules from the manger by the left forelimb under conditions of high food motivation). Animals were trained to perform operant movements in 30 min-long everyday sessions during 12 days. The duration of a single food-procuring movement was about 600 msec. Realization of the operant reflex was accompanied by clearly expressed motivational/affective reactions. The heart rate (HR) in the course of each operant movement sharply dropped (on the 10th day of training, by 12%, on average) with subsequent recovery of this parameter within 3–4 sec. In the course of 30-min-long training sessions, the mean HR gradually decreased (in the examined group, 7%, on average) within an interval from the 5th to the 20th min with subsequent recovery until the end of the training session. The mean numbers of Fos-ir neurons in the medullary nuclei of the ANS (Sol, IRt, CVL, RVL, Amb, 10, and MdD) of rats performing food-procuring movements (n = 4) were significantly (P < 0.05) greater than those in the control, and the intensities of c-fos expression in these structures corresponded to the following succession: Sol > IRt > CVL+RVL/CVL > RVL. Large Fos-ir neurons were observed in the dorsal motor nucleus of the n. vagus (10) and in the Amb/RAmb nuclei. In a considerable proportion of neurons of the Sol and single cells of the 10 and Amb, we observed double labeling (Fos-ir + NADPH-dr). Thus, operant food-procuring movements are accompanied by episodes of bradycardia related to each separate realization; in addition, a long-lasting tonic decrease in the HR developed. These autonomic reactions are mediated by the abovementioned medullary ANS nuclei. It is supposed that the respective weakening of inhibitory sympathetic effects on spindle receptors of the muscles involved in realization of the above operant movements can provide facilitation of generation of proprioceptive impulsation, facilitation of monosynaptic spinal reflexes, and, finally, an increase in the efficacy of targeted limb movements directed toward food procurement.     

The integrating role of biological motivation in the realization of feeding and drinking behaviors]

In chronic experiments on rabbits with preliminary alimentary or water deprivation electrical and mechanic activity was studied of the chewer muscle proper and of the esophagus in the process of animals food or water taking. It has been established that in patterns of electrical and mechanic activity of the chewer muscle proper and esophagus specific differences of alimentary and drinking behaviour of animals are reflected. Dominating motivation of different biological properties determines the specific integration of motoneurones of chewing and swallowing centers and peripheral contraction elements of digestive tract in the functional systems of alimentary and drinking behaviour.     

Acid-Base Balance Modulates Respiratory and Alimentary Behavior of the Mollusc Lymnaea stagnalis

An active reaction (change of pH) in hemolymph of the freshwater pulmonate mollusc Lymnaea stagnalis is studied in various physiological states: hunger, satiety, and alimentary excitation. In satiated animals the hemolymph pH is shifted to the acid area (7.6 ± 0.003) as compared with hungry animals (7.9 ± 0.05). The satiated individuals are characterized by an increased respiratory activity and decreased food consumption as compared with hungry animals. Acidification of the medium leads to an increase of excitability of the respiratory network interneurons (RPeD1, VD4, VD1/RPD2) and to inhibition of activity of the alimentary network interneurons (R/L CGC), whereas alkalization, to opposite effects. It is suggested that pH is one of factors coordinating activity of functional systems of Lymnaea stagnalis due to effect on neuronal correlates of the respiratory and alimentary behavior.     

Formation of temporary connections in dogs following destruction of the amygdaloid complex, head of the caudate nucleus and orbital cortex]

Ablation of the orbital cortical zones in dogs after ablation of the basolateral part of the amygdala and the caudate nucleus head considerably impeded the elaboration of secretory conditioned alimentary reflexes, without affecting the rate of elaboration of simple instrumental food-procuring reaction. The dogs lost however the capacity to differentiate non-reinforced stimuli from reinforced ones, which was revealed in both secretory and instrumental reactions.     

EEG-correlates of alimentary behavior in rabbits with different levels of hunger and satiety]

The electrical activity of the rabbit brain at different stages of hunger and satiation was correlated with the animal's behavioral reactions. It has been found that alimentary reactions are attended with the appearance of complex high-amplitude and high-frequency electrical potentials in the lateral hypothalamic area, which increased with the longer duration of the animal's hunger, as well as during search, in response to natural and conditioned alimentary stimuli, and when feeding. As satiation sets in, they fade and disappear after food refusal. It is assumed that this form of activity is an EEG expression of alimentary motivational excitation. Its constituent rhythms reflect the different components of alimentary excitation.