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Results for “Exploratory Behavior”

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At least 307 records · Page 17Linked to original sources

PubMed1984

Peer presence and the exploratory behavior of eighteen- and thirty-month-old children.

20 18- and 20 30-month-old children were observed in a situation requiring separation from the mother in order to play with attractive toys. An agemate was present for half the children but not the others. Peer presence facilitated leaving the mother and entering the playroom at both ages. Among 18-month-olds, the presence of the peer also shortened play bouts, increased unoccupied/self-solace behavior, and increased contact maintenance with the mother. Among 30-month-olds, however, the peer's presence did not have these effects. these children engaged in increased coordinate social interaction with the other child. Developmental changes occurring in the second and third year thus include the increased salience of agemates in supporting separation from the mother and exploration of the environment in the context of sustained social interaction.

Child Development↗

PubMed1986

Disturbances in exploratory behavior and functional recovery in the Y and radial mazes following dopamine depletion of the lateral septum.

The effects of 6-hydroxydopamine (6-OHDA) injected into the lateral septum in rats were investigated for spontaneous alternation behavior in a Y maze and for spatially oriented behavior in an 8-arm radial maze. The performance of the animals in these tests was assessed under two physiological states, food-satiated and food-deprived. The selective depletion of septal dopaminergic concentrations leads to behavioral disturbances in both the Y and the radial mazes. These deficits disappeared when the animals with 6-OHDA lesions were food-deprived. These results confirm other studies from our laboratory and support two conclusions. First, lesions of dopaminergic neurons lead to behavioral impairments which resemble those found after the total lesion of the structure they innervate. Second, these behavioral impairments are responsive to therapeutic treatments, manipulations of the internal or external environment, or the level of arousal, since under certain conditions a recovery of function can occur in the absence of dopaminergic neurons. These two points provide additional support for a nonspecific role for the dopaminergic neurons originating in the ventral tegmental area. These neurons could have a permissive role in the functioning of the forebrain structures they innervate.

Animals↗

PubMed1979

[Effect of mescaline on cerebral cholinesterases and on exploratory behavior in rats].

In this study the Authors had the purpose to evaluate the action of a psychotomimetic substance (mescaline) on behavior (exploring behaviour and spontaneous motility) and on cerebral biochemistry (cholinesterase activity) of rat. The mescaline has shown to be active both on behaviour (increasing the spontaneous motility) and on biochemistry (decreasing the total cholinesterase activity). From the examination of the results of this work it could be cautiously assumed the hypothesis that the behavioural effects of mescaline are related (at least partially) to modifications of the cholinergic system at the cerebral level.

Acetylcholinesterase↗

PubMedDate not supplied

[Role of the hypothalamus in originating disorders of exploratory behavior and learning in rats with excised nuclei of the locus coeruleus].

Open-field behaviour and emotionally differently reinforced learning were studied in male Wistar rats with bilaterally ablated Locus coeruleus. Histochemical analysis of the hypothalamic structures was carried out. Decrease of investigating activity and attention was found as well as disturbances of learning with emotionally-negative (painful) reinforcement. By means of histochemical methods, fluorescence characteristic for catecholamines was found to decrease sharply in paraventricular and supraoptic hypothalamic nuclei, eminentia medialis and the posterior lobe of the hypophysis.

Animals↗

PubMed1988

The ontogeny of exploratory behavior in the house rat (Rattus rattus): the mobility gradient.

Infants of rats and other mammals respond to a novel environment by becoming immobile, and then showing a process of motorial expansion called "warm-up." Starting from immobility, new types of movement are incorporated into the stream of behavior according to rather strict rules of order. Once a new type of movement has been performed, the infant reverts to it repeatedly. As a result, the earlier portion of the behavior appears stereotyped, giving the impression of an automatism. Later, as new types of movement are added to the infant's repertoire, the movement becomes increasingly rich and unpredictable, giving the impression of "free" behavior. The same rules of order operate within "warm-up" sequences of movement, and across such sequences, day by day. Concurrently, there is an increase in the amplitude of movements, resulting in a gradual expansion of the portion of the environment explored by the infant. The same rules of order seem to operate in the development of locomotion in more primitive vertebrates. In rats under the action of psychoactive drugs, the "warm-up" sequence is performed in reverse.

Aging↗

PubMed1979

[Effect of scopolamine on the memory of exploratory behavior in the mouse].

In the present work it has been evaluated the action of scopolamine on the extent of exploration in mice, whose exploring behaviour had been already earlier examined. Such behaviour has been evaluated using a hole-board. The goal has been to detect the influence of the substance on the short-term memory of mice. The method used has shown to be effective. By the exam of the results of this work it can be concluded that the scopolamine at a dose of 1 mg/kg has an evidence effect of short-time memory in mice by causing a hypomnesia.

Animals↗

PubMed2007

Extinction-induced "despair" in the water maze, exploratory behavior and fear: effects of chronic antidepressant treatment.

In former studies, we found evidence for the hypothesis that withdrawal of negative reinforcement presents a major source for stress and despair. Specifically, the removal of a hidden platform in the water maze induced extinction of previously reinforced escape behavior and behavioral immobility, indicative of "despair", which also correlated with indices of fear. Here, we tested the effects of antidepressants on extinction in the water maze, and expected that such drugs would attenuate the rate of extinction of a conditioned place preference (CPP) and also any emotionally relevant behavior that is induced by the loss of reinforcement, such as immobility. Adult male Wistar rats were trained to escape onto a hidden platform for 10 days. Daily treatment with desipramine hydrochloride (DMI, 10mg/kg) or fluoxetine (FLX, 10 mg/kg) commenced 1 day before the first of 11 extinction trials without the platform, administered 48 h apart, and continued thereafter, as the rats were tested in an open field and elevated-plus maze. As compared to controls, DMI increased the resistance-to-extinction of CPP, attenuated immobility, and increased wall climbing behavior. In the open field, DMI reduced activity levels, but was without effect on traditional fear parameters in the elevated-plus maze. FLX, by contrast, increased immobility during the extinction trials and fear in the elevated-plus maze. The withdrawal of reinforcement induced "despair" that was alleviated by the noradrenaline reuptake inhibitor DMI. The effects of the selective serotonin reuptake inhibitor FLX on immobility and fear may be explained in terms of its side effect profile.

Affect↗

PubMed1989

Age-determined changes in the effects of a newly synthetized cholinesterase inhibitor on exploratory behavior, memory and striatal cholinesterase activity in rats.

The newly synthetized cholinesterase inhibitor C-8 (a structural analogue of physostigmine) at a dose of 4 mg.kg-1 exerted no inhibitory effect on the spontaneous locomotor activity in 2-, 10- and 22-month old male Wistar rats. Upon open field test, C-8 facilitated the process of habituation in the rats of all three groups. In a passive avoidance situation (step-down and step-through) C-8 had a favorable effect on the memory of 22-month old rats mainly. C-8 inhibited the cholinesterase activity in the striatum of 2-month old rats by 29%, in 10-month old rats by 73%, and in 22-month old rats by 30%.

Aging↗

PubMed1997

Dissociable effects of selective lesions to hippocampal subsystems on exploratory behavior, contextual learning, and spatial learning.

Rats received excitotoxic lesions of different subsystems within the hippocampal system--either the hippocampus proper (cornu ammonis and dentate gyrus; hippocampal lesions) or the entorhinal cortex-subicular region (entorhinal lesions). Subsequently, their activity in an operant chamber was monitored both before and after footshock had been delivered (Experiment 1). Rats with hippocampal lesions showed enhanced activity before the delivery of footshock and reduced freezing after the delivery of shock. Rats with entorhinal lesions showed control levels of activity before the delivery of footshock and control levels of freezing after the delivery of footshock. Both types of lesion impaired spatial learning in a water maze (Experiment 2). These results suggest that the deficits arising from damage to the hippocampal system in contextual and spatial learning have different origins.

Animals↗

PubMed1987

Chronic imipramine effects on exploratory behavior in rats.

Approximately 100 days old hooded rats, socially isolated or group-housed since weaning, received 15 daily IP injections of isotonic saline, 10 mg/kg or 20 mg/kg of imipramine HCl. Following their last injection, the rats' active choices of a novel environment, frequencies of rearing and grooming, and cells entered in an exploration box were recorded. The drug treatment reduced rearing, ambulation and (for isolated rats only) grooming, but had no effect on novelty choices. There was a significant weight loss with the higher dose and (for males only) with social isolation during the drug treatment period. While imipramine reduced grooming in isolated but not group-housed rats, there were no other interactions between the two forms of treatment. It was concluded that, in spite of its sedative action on motor activity, chronic imipramine did not alter curiosity about a novel environment.

Animals↗

PubMedDate not supplied

[A comparative analysis of learning and exploratory behavior in rats with different resistances to stress exposures and to the brain monoamine level].

Wistar rats stable (S) to sound stimulus differed from the unstable (NS) ones by a heightened investigatory activity in condition of moderate stress in the open field test, by heightened reactivity to sensory stimuli of various modalities (somatosensory, visual and olfactory), lowered level of investigatory behaviour in the test of burrow chamber. S-rats differed from NS-animals by a higher ability to learning of goal-directed reaction and a lower ability to discrimination of different emotional influences. The results of biochemical analysis of the content of biogenic amines in various brain structures revealed in stable rats an increase of noradrenaline level and in non-stable ones--a higher level of dopamine and serotonin.

Animals↗

PubMed1989

[The regulatory effect of VIP on exploratory behavior of the rat and on the neuromediator level in the normal brain and in frontal lobectomy].

In chronic experiments on 35 rats, effects on the animals behaviour of intracerebroventricular administration of vasoactive intestinal peptide (VIP) and VIP antiserum were studied under the "open field" conditions before, and on, the 4th and 9th day after local (50%) extirpation of frontal cortex. Sham-operated animals have been used as a control. A considerable regulatory action of VIP on rats' research behaviour was shown (quantity of crossed quadrants, vertical rearing) on the 9th day after the lobectomy. After the operation, the content of noradrenaline (NA), dopamine (DA) and serotonin (5HT) was determined spectrofluorometrically in cortex and subcortical structures. The VIP seemed to exert a regulatory normalizing effect on the neurotransmitters balance in cerebral structures under frontal lobectomy conditions. The most considerable effects were observed in subcortical brain structures and were due to VIP antiserum administration.

Animals↗

PubMed1989

Effect of schistosomiasis mansoni on open-field exploratory behavior in mice.

The response of mice infected with Schistosoma mansoni to a novel environment has been investigated in an attempt to study the effects of the disease on brain cognitive function by using opto-varimix instrument and autotrack computer program. Two to 18 weeks infected mice showed lower ambulatory activities than their matched controls with the largest reduction occurring between weeks 6 to 10. Maximum effects were observed in week 8. The first 5 minutes of ambulatory activities, designated as the "first session", were 22.3% lower in infected mice as compared with controls. The decline in the first session activities of infected mice was slower than the controls. Infected mice showed fewer stereotype movements with maximum reduction in week 16 of infection. There was no correlation between mice ambulatory activities or stereotype movements and infection duration. The importance of these findings in relation to the course of the disease and the underlying mechanism(s) are discussed.

Animals↗

PubMedDate not supplied

[The characteristics of exploratory behavior in Wistar rats in a permanent inhomogeneous magnetic field].

The influence of weak perturbations (up to 300 microT) in the natural magnetic field (MF) (induced by the introduction of three constant magnets) on the problem task solving in complex maze was studied in two groups of Wistar rats. Under the action of inhomogeneous magnetic field there were no spontaneous change of the orienting for the explorative activity independently of the individual in the presence of the organization of goal-directed behaviour. Instead of the expected explorative activity, the stable and deep locomotor depression developed after orienting in a new environment. Such a phenomenon was manifested only against the background of informational loading. Nevertheless, under these conditions a short external stimulations resulted in even faster rat learning than in the control animals. It is suggested that the MF characteristics play a crucial role in the transformation of the orienting (unconditioned activity) into the explorative (cognitive) activity.

Animals↗

PubMed1999

Possible neural mechanisms involved in footshock stress-induced enhancement of exploratory behavior in mice.

The effect of inescapable footshock stress on open-field activity, as measured by the number of ambulations, was studied in male mice. Ambulations significantly increased after footshock stress, the most significant effect appeared after 20 min-stimulation and the effect decreased as footshock time lengthened. The footshock stress-induced enhancement of ambulation was inhibited by haloperidol (0.2, 0.5 and 1 mg/kg), phentolamine (5 and 10 mg/kg), mianserin (20 mg/kg), atropine (0.5, 1 and 2 mg/kg), naltrexone (10 mg/kg) and MK-801 (0.05, 0.1 and 0.2 mg/kg), but was not influenced by propranolol (5, 10 and 20 mg/kg) or diazepam (1, 2 and 5 mg/kg). Haloperidol (0.5 and 1 mg/kg) and mianserin (5, 10 and 20 mg/kg) also exerted an inhibitory effect on non-stressed normal mice. These results suggest that dopaminergic, alpha-adrenergic, cholinergic, opioidergic and N-methyl-D-aspartate (NMDA) receptor-mediated neurotransmission systems are involved in the footshock stress-induced ambulatory activation.

Animals↗

PubMed2006

Place-selective firing of CA1 pyramidal cells during sharp wave/ripple network patterns in exploratory behavior.

We observed sharp wave/ripples (SWR) during exploration within brief (<2.4 s) interruptions of or during theta oscillations. CA1 network responses of SWRs occurring during exploration (eSWR) and SWRs detected in waking immobility or sleep were similar. However, neuronal activity during eSWR was location dependent, and eSWR-related firing was stronger inside the place field than outside. The eSPW-related firing increase was stronger than the baseline increase inside compared to outside, suggesting a "supralinear" summation of eSWR and place-selective inputs. Pairs of cells with similar place fields and/or correlated firing during exploration showed stronger coactivation during eSWRs and subsequent sleep-SWRs. Sequential activation of place cells was not required for the reactivation of waking co-firing patterns; cell pairs with symmetrical cross-correlations still showed reactivated waking co-firing patterns during sleep-SWRs. We suggest that place-selective firing during eSWRs facilitates initial associations between cells with similar place fields that enable place-related ensemble patterns to recur during subsequent sleep-SWRs.

Action Potentials↗

PubMed1980

Emotionality and exploratory behavior following cortico-basomedial amygdala lesion in rat.

Twelve rats with amygdaloid lesion (CBM group) and 20 sham operated (Control group) were tested. Emotional reactivity evaluated by six category scale showed transient decrease in CBM group with respect to Control one. The CBM lesion enhanced the locomotor activity in electromagnetic activity meter in the initial phase of confinement in the apparatus. Open-field ambulation was higher in CBM rats than in controls on the first day of examination, while on the second day both groups showed similar locomotor activity. No between group differences were found in response to introduction of novel object. Both groups preferred to stay in box placed in open-field than move around the field. However, CBM rats were engaged in box exploration, whereas controls spent major proportion of time sitting motionless. These results indicate that CBM lesion increases some components of response to novelty. The pattern of changes and their transitory character suggest that cortico-basomedial region of the amygdala is involved in the control of processes underlying the initial phase of responding to novel environment.

Amygdala↗

PubMed2001

Vibrissal sense is not the main sensory modality in rat exploratory behavior in the elevated plus-maze.

Four groups of male Wistar rats were submitted to acute bilateral removal of mystacial vibrissae at different lengths from the follicle. Each group was divided into two subgroups, tested under high (150 Lux) and low environmental illumination (2 Lux). All the subjects were allowed to freely explore an elevated plus-maze for 5 min. Results indicated that rats tested under low illumination tended to explore the open arms more frequently and longer then rats tested under high illumination. When tested under low illumination, rats in the group that suffered whole vibrissa removal stayed longer in the open arms than those in the other groups but did not differ in the number of entries. The average increase in the length of open arm entries, rather than a decrease in aversion to the open arms, may be due to the need of more time to obtain information about the environment since there is no light and the vibrissae were removed. This effect was not seen with rats tested under high illumination, possibly because vision could be used to obtain relevant information.

Animals↗