Returning behavior in frontal rats.
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Animals↗
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Results for “Exploratory Behavior”
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[Placebo and motor activity of isolated and grouped mice].
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Animals↗
["Open field" rat behavior following exposure to a magnetic field].
The influence of the magnetic field on a complex physiological reaction in the "open field" test was studied in experiments on 160 rats. The behaviour in the "open field" was observed within three consecutive days simultaneously of control rats and those subjected directly before each test to a three to four hour general effect of a weakly pulsing magnetic field with a 0.3 T induction or a strictly constant magnetic field of 1.6 T. Individual behavioural reactions to the MF action were characterized by great variability and could be of different direction. According to mean data, the 0.3 T MF action depressed motor and investigating behaviour of the rats in the "open field". An increase of magnetic induction up to 1.6 T, far from enhancing the inhibitory effect, showed a tendency towards activation of behaviour in the "open field". Apparently, in conditions of the intensities used, pulsation is a biologically more significant characteristics of the magnetic field than the magnitude of induction.
Animals↗
Response to stimulus change following observation or exploration by the rat: a confirmation of differential effects of hippocampal damages.
The experiment attempted to confirm the previous finding that hippocampal lesions in rats affected the information acquired by distant observation of the brightness difference of the T-maze arms, but left the information intact when it was gained by maze exploration. An alteration was introduced in the latter procedure allowing a complete elimination of olfactory stimuli, which might be utilized as nonmemorial cues. Despite this alteration the results were virtually the same as previously. Following maze exploration the hippocampally lesioned rats tended to enter the arm that had been subsequently changed in brightness, similarly to control rats. However, unlike the controls, they responded on the chance level after distant observation. This finding is not compatible with Oltons hypothesis postulating the involvement of the hippocampus in the working memory, or with the OKeefe-Nadel theory of processing spatial information by the hippocampus.
Animals↗
Early behavioral abnormalities in mice due to scrapie virus encephalopathy.
The behavioral effects of scrapie virus infection, a slow degenerative disease of the central nervous system, were examined in mice. Testing was conducted at 50, 100, and 150 days postinfection and included open-field behavior, Y-maze alternation and activity, and two-way shuttle-box avoidance. The behavioral pathology was found to be task-specific rather than of a global nature. Furthermore, the effects observed could be classified as either early or late components of the disease. The relevance of this animal model to human presenile dementias is discussed.
Animals↗
[Short-term memory. An experimental model].
In the present work we aimed to elaborate an experimental model to evaluate and quantify the short-term memory in experimental animals, in this case in mice. It seemed ideal to us the employment of a spontaneous behaviour, i.e. the re-exploration of the hole board, automatically recorded by animals which had previously explored at a 24 h interval. The data obtained show that, when re-exploring, the animals show a statistically significant decrease, compared to the previous exploration. It can be concluded that the animals had a mnestical retention and that it can be validly quantified. This shows the validity of this experimental model, in order to study the short-term memory in mice.
Animals↗
[Inhibitory effect of scopolamine on recent memory of mice].
In this research the Authors have studied the action of scopolamine on the memorization of the explorative behavior of the mice. They gave scopolamine before each of the 2 explorations made at an interval of 24 h one from the other. The results obtained show that in these experimental conditions, scopolamine cancels the short-time memory in a more complete fashion compared to the only administration before the second exploration. The Authors advance the hypothesis that this effect of scopolamine can be in relationship to its action on the cholinergic system.
Animals↗
[Ontogeny of behavior in red squirrels (Tamiasciurus hudsonicus)].
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Animals↗
The effects of exposure time and retention interval on response to environmental change in rats.
Responses to change of visual stimuli in the environment were studied under 6 different exposure times and 3 different retention intervals in 18 groups. An increase in exposures from 1 to 3 and 5 min had a positive effect on the response-to-change frequency. The level observed after 5 min exposure did not alter significantly when exposures of 10 min and 15 min were applied, while a further increase in exposure time to 20 min reduced the number of responses to change. Elongation of retention intervals from 1 to 3 and 5 min decreased the response-to-change frequency after each exposure. In the case of optimal exposures (5-15 min) the decrease was from 80 percent to approximately 60 percent.
Animals↗
Behavioural and pituitary-adrenal characteristics of pigs differing by their susceptibility to the malignant hyperthermia syndrome induced by halothane anesthesia. 1. Behavioural measures.
Behavioural responses were compared in Pietrain pigs and in Large White pigs differing by their susceptibility to the malignant hyperthermia syndrome induced by halothane. Non reactive Pietran pigs (P--) displayed a higher level of locomotor activity in a new environment than either reactive Pietrain pigs (P+) or Large White pigs. Pietran pigs performed better in a latent learning proceudre (latency of approach or feeding response, after exploration of the new environment) and in a continuound P-- did not reach significance, but P+ pigs tended to be superior to P-- animals. The three groups did not differ on a measure of passive avoidance. These results suggest that Large White pigs are characterized by a lower ability to initiate active responding when confronted with aversive events. The same would be true when Pietrain positive pigs are compared with Pietrain negative pigs, although to a lesser extent.
Animals↗
Effects of age on open-field behavior of male rats.
As age advances, the performance of animal behavior declines gradually. The purpose of this study was to investigate the onset of age-related changes in open-field behavior of rats from a wide age spectrum. Male Long-Evans rats, ranging from 2 to 22 months, were placed in an open-field apparatus during the dark phase for a cumulative period of 28 min. Data were collected for the following parameters of open-field behavior: horizontal activity (HA), total distance (TD), stereotypy count (SC), vertical activity (VA), movement time (MT) and margin time (MGT). The highest value of HA, TD, SC and MT was found in rats at the age of 3 months. After 3 months, the values for these parameters gradually declined, subsequently reaching statistical significance by 6 months (HA, TD and SC) or 8.5 months (MT) of age. Maximum activity of VA occurred at 8.5 months of age and thereafter gradually declined with increasing age, however, no significantly statistical difference was reached as compared to the highest value. In contrast, the values for MGT gradually declined after 2 months of age, thereby reaching statistical significance by 11 months of age. These results indicate that the onset of age-related decline in open-field behavioral parameters can differ and the age-related changes in open-field behavior depends on observational parameters.
Age Factors↗
Hippocampal lesions disrupt an associative mismatch process.
Novel assays were used to assess inter alia whether the hippocampus is involved in detecting novelty per se or in an associative mismatch process. During training, rats received two audiovisual sequences (tone-left constant light and click-left flashing light). In both sham-operated control rats and those with excitotoxic hippocampal lesions, novel visual targets provoked an orienting response that habituated during training. Moreover, like sham-operated rats, rats with hippocampal lesions acquired associations between the elements of two audiovisual sequences. However, subsequent test trials in which the auditory stimuli preceding the visual targets were switched (click-left constant light and tone-left flashing light) provoked renewed orienting to the visual targets in sham-operated rats but not in hippocampal rats. These results support the view that hippocampal damage results in a failure to detect (or act on) mismatches that are generated when an auditory stimulus associatively evokes the memory of one visual stimulus and a different (familiar) visual stimulus is present in the environment.
Animals↗
Medial septum lesions disrupt exploratory trip organization: evidence for septohippocampal involvement in dead reckoning.
Rats organize their open field behavior into a series of exploratory trips focused around a central location or home base. In addition, differences in movement kinematics have been used to fractionate the exploratory trip into tour (i.e., sequences of linear movement or progressions punctuated by stops) and homeward (i.e., single progression direct to the home base) segments. The observation of these characteristics independent of environmental familiarity and visual cue availability has suggested a role for self-movement information or dead reckoning in organizing exploratory behavior. Although previous work has implicated a role for the septohippocampal system in dead reckoning based navigation, as of yet, no studies have investigated the contribution of the medial septum to dead reckoning. First, the present study examined the organization of exploratory behavior under dark and light conditions in control rats and rats receiving either electrolytic or sham medial septum lesions. Medial septum lesions produced a significant increase in homeward segment path circuity and variability of temporal pacing of linear speeds. Second, as an independent assessment of the effectiveness of the medial septum lesions, rats were trained to locate a hidden platform in the standard water maze procedure. Consistent with previous research, medial septum lesions attenuated learning the location of the hidden platform. These results demonstrate a role for the medial septum in organizing exploratory behavior and provide further support for the role of the septohippocampal system in dead reckoning based navigation.
Animals↗
Infantile (handling) stimulation and behavior in young Roman high- and low-avoidance rats.
The effect of infantile handling stimulation on exploratory and emotional behavior of Roman high- and low-avoidance (RHA/Verh and RLA/Verh) weanling rats was investigated. Postnatally handled and nonhandled, 4-week-old males and females from both psychogenetically selected lines were exposed to a hexagonal tunnel maze, including an illuminated central arena. Postnatal handling increased exploratory behavior and decreased emotional reactivity as expressed by increased entries into the central arena and a reduction in defecations in both lines of rats. These effects were more pronounced in the RLA/Verh rats. In agreement with earlier studies using nonselected adult rats, the females of both lines (especially those from the RHA/Verh line) were more sensitive than males to the positive influences of early stimulation.
Animals↗
The effects of methylphenidate and maturation on exploratory activity in rats.
Treatment of attention-deficit hyperactivity disorder with stimulants such as methylphenidate reduces motor activity and improves performance of tasks requiring attention, learning, and memory. The present study reports the patterns of behavioral activity of rats of different ages, and the effect of methylphenidate on the behavioral activity. The behavioral activity of Wistar male rats was measured on the nine hole-board apparatus. In experiment I, the behavioral activity of rats from three age groups (4, 8 and 12 weeks old) were measured in terms of the activity time, specific exploratory behavior, diverse exploratory behavior and defecation number. The rats were re-exposed to the hole-board again every two weeks until they 14 weeks old. The younger rats showed higher activity level compared to the older rats. The activity level decreased as the rats grew older. The younger rats also showed more diverse exploratory behavior, but less specific exploratory behavior compared with the older rats. These suggested that the younger rats may be more hyperactive in nature, and less prone to focus on the specific targets. In experiment II, the methylphenidate (4 mg/kg, i.p.) injected rats showed higher activity level than the controls across the three age groups. The exploratory behavioral patterns were not significantly different among the three age groups. This suggests that the methylphenidate injection raises the motor activity level without affecting the exploratory tendency of rats.
Aging↗
Exploratory factor analysis in behavior genetics research: factor recovery with small sample sizes.
Results of a Monte Carlo study of exploratory factor analysis demonstrate that in studies characterized by low sample sizes the population factor structure can be adequately recovered if communalities are high, model error is low, and few factors are retained. These are conditions likely to be encountered in behavior genetics research involving mean scores obtained from sets of inbred strains. Such studies are often characterized by a large number of measured variables relative to the number of strains used, highly reliable data, and high levels of communality. This combination of characteristics has special consequences for conducting factor analysis and interpreting results. Given that limitations on sample size are often unavoidable, it is recommended that researchers limit the number of expected factors as much as possible.
Animals↗
Brain mechanisms involved in ACTH-induced changes of exploratory activity and conditioned avoidance behavior.
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Adrenocorticotropic Hormone↗
Emotional behavior and arrhythmias induced in cats by hypothalamic stimulation.
As the relationship between emotional behavior and electrocardiographic (ECG) change induced by hypothalamic stimulation is poorly understood, eighty-four points in various areas within the hypothalamus in conscious cats were stimulated electrically through chronically implanted electrodes, the objective being to clarify the behavior accompanying ECG changes, in particular poststimulus arrhythmias. Forty-one of 84 points elicited behavioral patterns such as defense reaction, pseudo-rage and restlessness (classified as group A), and in twenty-one (51%) of these 41 points arrhythmias occurred after cessation of stimulation. Forty-three of 84 points elicited behavioral patterns including predatory, exploratory and other behavioral responses (classified as group B), and in three (7%) of 43 points, poststimulus arrhythmias followed. Under light anesthesia, stimulations of twofold current intensity were applied at these points, and the incidences of the arrhythmias did not change in either group. The arrhythmia-inducing area in the cases of group A was found to lie dorsal and caudal to the optic chiasma and to extend caudally in the fornix. Three points in the cases of group B were located in the outer area of the aforementioned area. These studies showed that arrhythmias and group A behavior were observed mainly from stimulation of the anterior hypothalamus, whereas stimulation of other areas of the hypothalamus, including the lateral and the posterolateral hypothalamus, produced group B behavior and no arrhythmias.
Aggression↗