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At least 1,765 records · Page 98Linked to original sources
PubMed2005

Anxiolytic-like effects of ginsenosides on the elevated plus-maze model in mice.

In a previous study, we reported that ginseng extract has anxiolytic-like effects in the elevated plus-maze model and that the ginseng saponin fraction plays an important role. This experiment was performed to investigate the anxiolytic-like effects of ginsenosides Rb1, Rg1, Rg3-R, and Rg3-S, and the Rg5 and Rk mixture isolated from the ginseng saponin fraction in the elevated plus-maze. Furthermore, the anxiolytic-effects of Rb1, Rg1, Rg3-R, Rg3-S, and the Rg5 and Rk mixture were compared with those of a well-known active anxiolytic drug (diazepam). The oral administration of ginsenoside Rb1 significantly increased the number of open arm entries and the time spent on the open arm compared with those in the vehicle-treated group. Ginsenoside Rg1 and the Rg5 and Rk mixture also significantly increased the number of open arm entries and the time spent on the open arm. However, ginsenosides Rg3-R and Rg3-S did not increase the number of open arm entries or the time spent on the open arm. On the other hand, ginsenoside Rb1 and the Rg5 and Rk mixture decreased locomotor activity in a manner similar to diazepam. These data indicate that ginsenosides Rb1, Rg1, and the Rg5 and Rk mixture have anxiolytic-like effects, but ginsenosides Rg3-R and Rg3-S do not in this model. We provide evidence that some ginsenosides may be useful for the treatment of anxiety.

Animals↗
PubMed1995

Effects of gentling on open-field behaviour of Wistar rats in fear-evoking test situation.

The effect of individual gentling on open-field behaviour of adult male Wistar rats was studied. Dark open-field evoked prey-like behaviour both in the gentled and in the nonhandled rats. Escape activity dominated in both groups although some habituation as a function of trials occurred. The effects of gentling were mainly seen in the quality of the fear-reaction as a result of reduced fear of human contact. Parameters that differentiated the 2 groups were middle field ambulation, middle field rearing and passive motionlessness.

Analysis of Variance↗
PubMed1975

Developmental and behavioral changes in the rat during chronic exposure to lead.

Young male and female Sprague-Dawley rats were given drinking water containing 5 or 50 ppm Pb for 40 days prior to mating. Pregnant females were continued on these regimens throughout gestation and lactation. After weaning the offspring were similarly exposed through adulthood. Reflex development, body weights, and locomotor activity were measured in the offspring. Significant delays were noted in the development of the righting reflex at 5 and 50 ppm and in eye opening at 50 ppm. No difference was observed in development of the startle reflex at either dose. Mean body weights of treatment groups during this developmental period were not significantly different from controls. Locomotor activity was measured in adult males utilizing a residential maze. Both levels of lead produced a significant reduction in locomotor activity. When groups were treated with d-amphetamine (4.0 mg/kg subcutaneous), lead treatment caused a dose-related diminution in the amphetamine-induced hyperactivity. These results indicate that rats exposed to low levels of lead from conception until adulthood show a delay in nervous system development. As adults, these animals exhibit hypoactivity and decreased responsiveness to amphetamine.

Aging↗
PubMed2006

Two item response theory models for analysing normative forced-choice personality items.

This paper proposes two unidimensional item response theory (IRT) models for analysing normative forced-choice personality items. Both models are derived from a common theoretical framework and arise as a result of different assumptions regarding the mechanism of choice. The simplest mechanism gives rise to the one-parameter normal-ogive model. The second mechanism gives rise to a new IRT model, which is closely related to the Coombs-Zinnes probabilistic unfolding model. The second model is compared theoretically to the normal-ogive model in terms of item characteristic curves and amount of item information. Next, procedures for estimating the respondent and the item parameters in the second model are described. Finally, both models are empirically compared by using two well-known personality measures.

Arousal↗
PubMed2004

Higher order memories for objects encountered in different spatio-temporal contexts in mice: evidence for episodic memory.

The ability to build higher order multi-modal memories comprising information about the spatio-temporal context of events has been termed 'episodic memory'. Deficits in episodic memory are apparent in a number of neuropsychiatric diseases. Unfortunately, the development of animal models of episodic memory has made little progress. Towards the goal of such a model we devised an object exploration task for mice, providing evidence that rodents can associate object, spatial and temporal information. In our task the mice learned the temporal sequence by which identical objects were introduced into two different contexts. The 'what' component of an episodic memory was operationalized via physically distinct objects; the 'where' component through physically different contexts, and, most importantly, the 'when' component via the context-specific inverted sequence in which four objects were presented. Our results suggest that mice are able to recollect the inverted temporal sequence in which identical objects were introduced into two distinct environments. During two consecutive test trials mice showed an inverse context-specific exploration pattern regarding identical objects that were previously encountered with even frequencies. It seems that the contexts served as discriminative stimuli signaling which of the two sequences are decisive during the two test trials.

Analysis of Variance↗
PubMed2001

Interference of propylene glycol with the hole-board test.

Experimental drugs and/or plant extracts are often dissolved in solvents, including propylene glycol. Nevertheless, there is evidence for psychoactive properties of this alcohol. In this study we found that in the hole-board test 10% propylene glycol did not modify the head-dipping behavior. However, 30% propylene glycol induced an increase in the number of head-dips (46.92 +/- 2.37 compared to 33.83 +/- 4.39, P<0.05, ANOVA/Student-Newman-Keuls), an effect comparable to that obtained with 0.5 mg/kg diazepam (from 33.83 +/- 4.39 to 54 +/- 3.8, P<0.01, ANOVA/Student-Newman-Keuls). These results demonstrate that 30% propylene glycol has significant anxiolytic effects in this model and therefore cannot be used as an innocuous solvent.

Animals↗
PubMed1974

Reading-related behavior in an open classroom: effects of novelty and modelling on preschoolers.

Eight preschool children were exposed initially to an unstructured (open) classroom in which, among other objects, a dozen different books were continuously available. Samples of the subjects' behavior over several weeks documented a very low frequency of reading-related activity (attention to books). Introduction of novel books into the classroom increased some children's reading-related behavior, but adults who modelled reading by reading aloud produced larger and more stable increases of such behavior. There was also a relative increase in frequency of independent and a relative decrease in mutual-peer reading-related activity, possibly as a result of modelling. The study calls attention to the need to evaluate the open-classroom setting in a manner compatible with the experimental analysis of behavior in other applied settings-a manner that is also consistent with the real aims of open education.

Aptitude↗
PubMed1976

Effects of stimulus incongruity, task demand, and induced involvement on amplitude of GSR.

Previous investigations into the arousing effects of incongruity have not only reported inconsistent findings but have displayed the limitation of using only two levels of incongruity. An experiment using four levels of incongruity confirmed the hypothesized positive linear function between incongruity and arousal (as measured by GSR amplitude). However, the results of two additional experiments confirmed the hypothesis that the marked arousing effects of incongruity were attributable at least in part to the demands of the task employed which included subjects having to choose and verbally commit themselves to one of the alternatives. The interaction between incongruity and degree of involvement engendered by the task demand suggests that involvement may facilitate the arousing effects of additional collative variables such as novelty, uncertainty, and complexity.

Arousal↗
PubMed1995

Transfer of odd-item search performance in a chimpanzee (Pan troglodytes).

An adult female chimpanzee (Pan troglodytes) who was trained only on odd-item search with a large number of items was tested for transfer of the odd-item search performance to new stimuli and to minimal items (1 target and 2 uniform distractors). The subject showed transfer to new target-distractor pairs when the number of items was large enough but showed no transfer to a minimal display even when the trained (old) target-distractor pair was presented. The results suggest that her performance on odd-item search was controlled mainly by perceptual cues such as pop-out of the target among the uniform distractors but not on relational cues such as the oddity rule.

Animals↗
PubMed1998

Locomotor activity and defecation of rats observed alone and in pairs in repeated open-field sessions.

Several experiments with independent groups have shown social effects on open-field defecation and locomotor activity in male rats. In this experiment these social effects were studied with a different methodological approach, namely, with repeated measurements. One group of 8 animals was tested always alone in an open field over 10 trials on successive days. The second group of 16 animals was also tested alone on Days 1 to 4 and on Day 9, while they were placed in the open field with a conspecific on Days 5 to 8 and again on Day 10. There was markedly reduced defecation and enhanced locomotion with the conspecific present, while with the absence of the conspecific on Day 9 the scores again reached the level of the rats always tested alone. Therefore, the social effects on defecation and locomotion are very robust phenomena which can also be shown with dependent measurements.

Animals↗
PubMed2004

Sensation seeking and symptoms of disruptive disorder: association with nicotine, alcohol, and marijuana use in early and mid-adolescence.

This study examined the association of Sensation Seeking and symptoms of Disruptive Disorders and investigated the associations of each with the risk of nicotine, alcohol, and marijuana use in 11- to 14-yr.-old boys and girls from psychiatric and pediatric clinics (n = 206). Sensation Seeking and symptoms of Disruptive Disorder were significantly related, and both were associated with drug use. In particular, Sensation Seeking was strongly associated with drug use in early and mid-adolescents seen in a clinical setting. Measurement of Sensation Seeking and symptoms of Disruptive Disorder should help identify and characterize youth who are at increased risk for drug use during early and mid-adolescence-a time when onset of use may be a harbinger of long-term habit.

Alcoholism↗