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PubMed1984

Effects of toxicosis on the predatory behavior of the golden hamster (Mesocricetus auratus).

The purpose of this study was to measure the effects that toxicosis had on the hamster's predatory behavior and to compare these results with those found in previous studies with grasshopper mice. A 0.15 M LiCl injection caused hamsters to develop a greater aversion and to inhibit their feeding and attack responses more frequently toward a house cricket than did a similar injection of NaCl. The added presence of an almond coating on the cricket prolonged the number of days that a hamster exhibited an aversion toward the prey and an inhibition to attack. Essentially, the inhibitory effects from toxicosis in the hamster paralleled those found with the grasshopper mouse. The differences in these inhibitory effects are attributed to inherent differences in the attack responses of the two rodents.

Animals↗
PubMed1984

Encounters in predator-prey systems: a simple discrete model.

Predator-prey systems are often described by exploitation models. These models can mimic experimental data very accurately, but it is sometimes difficult to realize the relationships between the models and the behavior of individual predator and prey animals. A simple discrete model is proposed here that tries to elucidate the connections between: the animals' movements, the predator/prey encounters; and the dynamics in the system as globally represented by the exploitation models. In these models, the term "area of discovery" plays an essential role. This term is shown to be a predictable coefficient that is composed of measurable physical properties of the analyzed predator-prey system. The model takes into account that predators and prey in experimental systems often do not search randomly but prefer some parts of the test area. The model is applied to the mite system Phytoseiulus persimilis/Tetranychus urticae under simple artificial conditions.

Animals↗
PubMedDate not supplied

Effects of dexamethasone on the body weight set point of rats.

Adult Wistar male rats were given dexamethasone in their drinking water. Food-hoarding behavior was measured repeatedly, and plotted against the animals' body weights. Body weight set point was estimated as the intersection of the regression line of hoarding with the X axis, i.e. as the threshold at which hoarding appears when body weight drops, and disappears when body weight returns to its initial value. Body weight set point was obtained before and during dexamethasone treatment. Control rats underwent the same sequence without dexamethasone in their drinking water. The hoarding threshold was raised when rats ingested low doses of dexamethasone, and was lowered when they ingested high doses. These results are discussed in the light of CRH as the main signal for the body weight set point.

Animals↗
PubMed1987

Effect of chlorpheniramine on muricide induced by thiamine deficiency: pharmacokinetic and behavioral studies.

Chlorpheniramine (5-10 mg/kg) showed a dose-dependent suppressive effect on muricide induced by thiamine deficiency at 1 hr after oral administration. The ED50 value for muricidal suppression was about 7.1 mg/kg (95% confidence limits, 5.4-9.3 mg/kg). The maximum effect of muricidal suppression lasted for 1-2 hr after oral dosage (10 mg/kg). Chlorpheniramine was detectable at 10 min in the blood and brain of thiamine deficient killer-rats by using a high-performance liquid chromatographic method. Maximum brain and blood levels of chlorpheniramine appeared at 45 and 60 min, respectively. In terms of regional distribution, the highest levels were measured in the limbic system, especially in the hippocampus. Although neither blood nor brain levels of chlorpheniramine reflect its pharmacological activity, it can easily enter the brain and suppress muricide more potently than imipramine.

Aggression↗
PubMed1976

A comparison of hypothalamically induced biting attack with natural predatory behavior in the cat.

A comparison of biting attack induced by electrical stimulation of the cat hypothalamus with natural feline predatory attack revealed a high degree of similarity between the two behaviors. All major components of natural attack could be elicited by hypothalamic stimulation in cats not showing spontaneous attack, including stalking approach to prey, holding and pinning of the prey with forepaws, biting directed to the head and neck, prey kicking, prey carrying, and prey eating. Differences between natural and elicited attack appeared to be related to the range of completenes of elicited attack, the greater intensity of elicited attack, and the presence of unrelated responses induced by hypothalamic stimulation. Results support the view that hypothalamic stimulation facilitates sensorimotor mechanisms for separate response components, which are highly sensitive to specific stimulus features of the environment and potential goal objects.

Aggression↗
PubMed1994

Learned olfactory discrimination versus innate taste responses to amino acids in channel catfish (Ictalurus punctatus).

Intact channel catfish conditioned to the L-amino acids, proline, arginine, alanine, and lysine, discriminated these stimuli from all other amino acids tested. Behavioral structure-activity tests indicated that L-pipecolate was the only effective agonist of the L-proline conditioned response. For channel catfish in which one of the paired olfactory organs was surgically removed, the number of turns to the conditioned stimulus was 40% fewer than those of intact catfish; however, these semiosmic channel catfish discriminated the conditioned from nonconditioned stimuli, as evidenced by their responding to the conditioned amino acid, with a two- to threefold greater number of turns than to the nonconditioned amino acids. Irrespective of the number of conditioning trials attempted, catfish with both olfactory organs removed were unable to discriminate the conditioned from the nonconditioned stimuli.

Amino Acids↗
PubMed1984

Zimeldine: a review of its effects on ethanol consumption.

This review evaluates the literature and describes an extensive series of experiments which examined the effects of zimeldine , its metabolite norzimeldine and other serotonin and norepinephrine reuptake inhibitors on voluntary ethanol consumption in rats. The results of these experiments indicate that drugs which specifically inhibit serotonin reuptake are capable of decreasing voluntary ethanol consumption. The behavioral mechanism through which these drugs exert their effects seems to be extinction of the primary reinforcing properties of alcohol. These effects seem to be partially attenuated both by drugs which modulate the norepinephrine system as well as by the serotonin postsynaptic receptor blocker methergoline. The data presented in this review are discussed in terms of the involvement of the serotonin and norepinephrine systems in the mechanism of action of these drugs. In addition, several alternative hypotheses concerning the nature of the phenomenon are offered. Finally, the implications of these data for the possible development of a treatment procedure for problem drinkers is discussed.

Alcohol Drinking↗
PubMed2001

A few minor suggestions.

We agree with almost all of the analysis in this excellent presentation of the molecular view of avoidance behavior. A few suggestions are made as follows: Referring to response-generated stimuli as ''readily observable" seems not quite right for the kinesthetic components of such stimuli, although their scientific legitimacy is not questioned. Interpreting response-generated stimuli as a form of positive reinforcement is contested, and an alternative interpretation is offered. A possibly simpler interpretation of the Sidman (1962) two-lever experiment is suggested. We question Dinsmoor's (2001) explanation for warning stimuli not being avoided, except for the reference to the weakness of third-order conditioning effects. A final question is raised regarding the nature of the variables that are responsible for the momentary evocation of the avoidance response.

Animals↗
PubMed1999

Sequential search and the influence of male quality on female mating decisions.

The patterns of phenotypic association between mated males and females depend on the decision rules that individuals employ during search for a mate. We generalize the sequential search rule and examine how the shape of the function that relates a male character to the benefit of a mating decision influences the threshold value of the male trait that induces females to terminate search. If the fitness function is linear the optimal threshold value of a male character increases with the slope of the function. The phenotypic threshold criterion declines, all else being equal, if the fitness function is made more concave (or less convex) by an increase of the risk of the function. The expression of the trait in females has no effect on the optimal threshold value of a male character if the fitness function is linear and phenotypic values combine additively to influence the benefit of a mating decision; the phenotypic threshold criterion is ubiquitous among females. A convex fitness function induces females with high trait values to adopt a relatively high phenotypic threshold criterion, whereas a concave fitness function induces such females to adopt a low threshold value for the male trait. Thus, linear, convex and concave fitness functions effect random, assortative and disassortative combinations of phenotypes among mated individuals, respectively. Changes of female search behavior induced by changes of the distribution of a male character similarly depend on the shape of the fitness function. A variance-preserving increase of male trait values produces a relatively small increase of the threshold criterion for the male character if the fitness function is concave, relative to conditions in which the fitness function is either linear or convex. Our results suggest that a sequential search rule can in principle induce the kinds of mating patterns observed in nature and that the phenotypic association between mated individuals is likely to depend on how a male character translates into fitness, the distribution of the trait among males and attributes of searching females.

Animals↗
PubMed2006

Spatial cognition based on geometry and landmarks in the domestic chick (Gallus gallus).

Recent evidence suggest that encoding of spatial information based on extended surfaces may differ from encoding based on discrete arrays of local elements. Here we investigated the use of these different frames of reference in domestic chicks. Chicks were trained to search for food hidden under sawdust in the center of the floor of a square-shaped landmark array, with its center in coincidence with the center of a square-shaped enclosure. Displacement of the array to a corner caused a shift of searching behavior toward the array, the search activity spanning between the center of the arena and the center of the array. After changing distances between landmarks, chicks still searched in the central area. Asymmetries were apparent in chicks tested in monocular conditions, with left-eyed chicks being more affected by the overall enclosure and right-eyed chicks by local landmarks. These results suggest that chicks can use both distances from extended surfaces and local information provided by the landmarks of the array to orient in space. However, chicks do not seem to perceive the array as a whole configuration, rather they tend to rely only on single landmarks to locate the goal.

Animals↗
PubMed1997

The food-hoarding threshold is not raised by acute intraventricular NPY in male rats.

We studied the influence of acute intracerebroventricular (i.c.v.) NPY on the relation existing in the rat between food-hoarding behavior and the body weight of the animals. Six male rats were trained to feed every day from 1000 to 1200 h. Then, their threshold for the onset of food hoarding was measured from the intercept of the regression line relating the food hoarded during meal time (Y axis) to the body weight (X axis). Thirty minutes before the hoarding session, the rats were injected i.c.v. with either 4 micrograms of NPY or saline control. The mean threshold for food hoarding was not modified after NPY. Mean food intake during the hoarding sessions was also unchanged. These results suggest that intracerebral NPY at 4 micrograms did not acutely alter the set-point for body weight regulation.

Animals↗
PubMed2002

Feeding behavior of Lutzomyia pseudolongipalpis (Diptera: Psychodidae), a putative vector of visceral leishmaniasis in Venezuela.

Lutzomyia pseudolongipalpis Arrivillaga & Feliciangeli is the first new sand fly species in the L. longipalpis species complex that has been formally described since it was separated by genetic as well as by morphological characters. It is the putative vector of the American visceral leishmaniasis in La Rinconada, Curarigua, a restricted focus in central western Venezuela. We investigated the feeding behavior of this species. The blood meals from 210 of 429 (48.9%) engorged females caught by CDC light traps were identified by a dot enzyme-linked immuno-absorbent assay using antisera against humans and common domestic animals. We propose a new index, the host selectivity index, which is the number of sand flies fed on a given host relative to the available biomass of that host, as an indicator of the feeding behavior of this phlebotomine sand fly. The host selectivity index is compared with the forage ratio, which is the percentage of sand flies fed on a given host by the percentage which that host represented in the total census of available animals and humans. The most attractive animal for L. pseudolongipalpis in Curarigua was the dog, whereas humans were shown to be relatively unattractive. However, not only selectivity or biomass, but also the accessibility to this host may have influenced these results. The low population density of dogs and the low accessibility of L. pseudolongipalpis to humans in relation to domestic animals might help to explain the sporadic transmission of visceral leishmaniasis in this focus.

Animals↗
PubMed1995

Functionally distinct memories for imprinting stimuli: behavioral and neural dissociations.

Precocial chicks exposed to a stimulus subsequently approach that stimulus in preference to other, novel stimuli. Previous investigations of the neural basis of these imprinting preferences suggest that imprinting training results in the formation of two memories. The first memory is formed rapidly and is located in the intermediate and medial part of the hyperstriatum ventrale (IMHV) of the left hemisphere; the formation of the second, in another memory system, S', takes several hours and can be prevented by a lesion placed in the right IMHV soon after training. The results of the present study suggest that the functional characteristics of these memories differ. Although memories in both left IMHV and S' supported imprinting preferences (Experiments 1a and 2a), only memories in S' influenced the acquisition of a heat-reinforced discrimination in which imprinted objects served as discriminanda (Experiments 1b and 2b).

Animals↗
PubMedDate not supplied

[Dynamics of reorganization of instrumental food getting behavior of monkey under conditions of reinforcement delay].

Six adult monkeys (Macaca fascicularis) were trained to switch on a lamp by pressing the lever, to hold the lever for not less than 1 s (the lamp being switched on), and get a portion of food. After reaching a learning criterion, the delay between the lever pressing and food reinforcement was increased to 2.5 s. The experimental procedure was repeated in three experimental sessions with 2-month between-session intervals. It was shown that the retraining process after the uneven change in the delay duration developed in three stages: (1) stage of emotional hyperreactivity that reflected a mismatch between the cation and absence of the expected result; (2) stage of intermediate stabilization, when the percent of efficient attempts was the same as under conditions of 1-s delay; (3) stage of purposive instrumental lever holding till the moment of reinforcement presentation.

Animals↗
PubMed2002

Nucleus accumbens dopamine and discriminated approach learning: interactive effects of 6-hydroxydopamine lesions and systemic apomorphine administration.

RATIONALE: Although dopaminergic mechanisms have been implicated in incentive motivational processes, their role in appetitive conditioning remains poorly understood. OBJECTIVES: To investigate the effects of dopamine (DA) depleting lesions of the nucleus accumbens and the direct acting dopamine receptor agonist apomorphine on the learning of discriminated appetitive approach behavior in a Pavlovian autoshaping paradigm. METHODS: Rats received bilateral infusions of either phosphate-buffered saline (shams) or 6-hydroxydopamine (lesions) directly into the nucleus accumbens. Ten days later, rats were trained on an autoshaping task whereby a previously neutral light stimulus was paired with food reward. Presentation of another stimulus (CS-) was never followed by reward. Over 100 pairings subjects developed a conditioned response of approaching the reward-predictive stimulus (CS+). Prior to each autoshaping session subjects were administered either saline (1 ml/kg SC) or apomorphine (30 microg/kg; 100 microg/kg), in a between-subjects design. RESULTS: Lesioned subjects showed a delay in the acquisition of discriminated approach and were insensitive to a subsequent change in the contingency of the task whereby approaches to the CS+ now prevented food delivery. Low dose apomorphine profoundly impaired learning in both sham and lesioned subjects. Despite increasing the overall number of CS+ and CS- approaches, the higher dose of apomorphine allowed discriminated approach in sham-operated animals only. CONCLUSIONS: These data are compatible with the hypothesis that nucleus accumbens dopamine serves to energize rather than guide conditioned approach to appetitive cues. They also support the notion that DA inputs in this region confer flexibility of approach to cues predictive of reward.

Animals↗
PubMed2002

Early experience with the artificial nipple.

The present study examined the newborn pup's responsiveness to artificial nipples that differed in length and width. In a series of experiments, pups were: exposed to a long (5.0 mm), thin (1.0 mm) nipple or a short (2.0 mm), fat (2.5 mm) nipple and their immediate behavioral responses including oral grasping were recorded and quantified (Experiment 1); preexposed to one artificial nipple and then reexposed to another artificial nipple to determine how early nipple experience affected subsequent responding to the artificial nipple (Experiment 2); videotaped to characterize details of oral grasping and to develop a technique for measuring depth of nipple entry into the pup's mouth (Experiment 3a); provided early nipple experience to see how depth of nipple entry into the pup's mouth changed when pups were reexposed to another artificial nipple (Experiment 3b); and exposed to an artificial nipple to determine how early nipple experience changed the pattern of oral grasping and ingestion of milk from a surrogate nipple (Experiment 4).

Analysis of Variance↗
PubMed2002

Mutual influence of the maternal hen's food calling and feeding behavior on the behavior of her chicks.

It is widely accepted that brooding hens attract their chicks to food by food calling, but until now, the concurrent behavior of hens and chicks has never been investigated in depth. This study provides a detailed analysis of both the behavior of brooded chicks and the distance to their mother in relation to her feeding sequences, and whether they contained food calling. Our results revealed that brooding hens utter food calls while pecking, especially when their chicks are not feeding and/or have been at some distance for several seconds. Chicks' response to their mother's feeding activities was more pronounced in the presence than in the absence of food call. Chicks responded to this call by approaching their mother and increasing their pecking; their response became more efficient as they grew older. We thus consider food calls as an arousal vocalization that directs the chicks' attention to a food item chosen by a hen.

Age Factors↗
PubMed2006

Microinfusions of neurotensin antagonist SR 48692 within the nucleus accumbens core impair spatial learning in rats.

The involvement of neurotensin (NT) within the nucleus accumbens core (NAC) in behavior has been sparsely investigated. Moreover, little is known of what role NT within the ventral striatum has on spatial learning. The present study investigated whether NT receptors in the NAC are implicated in learning of spatial information. Male Long-Evans rats were trained on a food search spatial learning task. Rats were microinfused with either NT antagonist SR 48692 (50 nM/0.5 =L) or saline in the NAC before each training session. Rats treated with SR 48692 made more reference and working memory errors during the acquisition of spatial learning than did rats infused with saline. These results suggest that NT receptors contribute to NAC-mediated spatial learning.

Animals↗