During playful interactions, rats emit increased levels of 50-kHz vocalizations. It is possible that these vocalizations are used as play signals that promote and maintain playful contact. The study investigated this possibility. It was predicted that if these vocalizations are used as play signals, they should be more prevalent (1) before an attack, (2) in […]
Purpose: Young children have a high risk of concussion or mild traumatic brain injury (mTBI). Children often appear healthy soon after mTBI, but some have pervasive cognitive and/or motor impairments. Understanding underlying mechanisms recruited after concussion may help for return to play protocols and mitigating what might be lifelong impairments. Methods: We investigated molecular and […]
Handling of laboratory rats can increase physiological and emotional stress, leading to a fearful relationship with humans. We hypothesized that the affective quality of handling techniques used during routine care influences the animals’ fear of humans. We assessed responses of male Sprague-Dawley rats (N= 32) to four handling treatments provided by caretakers from 57 to […]
Robbing and dodging is a well-documented food protective behaviour in rats. Recently, we demonstrated that a simple cybernetic rule, gaining and maintaining a preferred interanimal distance, can account for much of the variability in dodging by rats. In this paper, the field cricket, Teleogryllus oceanicus, was used to test whether or not the same or […]
During play fighting, rats attack and defend the nape and during the course of this competitive interaction, they may adopt a configuration in which one animal stands over its supine partner (i.e., pin). Because the pin configuration is typically frequent and relatively easy to identify, it has been widely used as a marker to detect […]
In a series of 3 experiments on rats, 2 hypotheses were tested: (a) that damage to the orbital frontal cortex (OFC) would alter the socially relevant context for executing defensive responses but not their performance and (b) that damage done to the OFC in early infancy would produce more deficits in social behavior than similar […]
Analysis of the body targets attacked and defended during play? fighting by juvenile Djungarian hamsters Phodopus campbelli revealed that about 70% of all attacks were directed at the mouth. If successfully contacted, the mouth was briefly licked and nuzzled. The remaining playful attacks were gentle bites directed at the rump, and to a lesser extent, […]
Handling small animals such as rats can lead to several adverse effects. These include the fear of humans, resistance to handling, increased injury risk for both the animals and the hands of their handlers, decreased animal welfare, and less valid research data. To minimize negative effects on experimental results and human-animal relationships, research animals are […]
The dynamic aspect of behavior is exaggerated during social interactions such as sex, combat and rough-and-tumble play where the movements of the two animals involved continually influence one another. The behavioral ‘markers’ abstracted from this stream can greatly influence the conclusions drawn about the effects of experimental procedures and how changes during development are interpreted. […]
Although cataleptic rats do not spontaneously orient, scan, or walk, they will cling, stand, right themselves in the air, and resist being displaced from a stable position (Schallert, Whishaw, De Ryck, & Teitelbaum, 1978). Morphine produces a state of immobility in which all reflexes used for stable static support (e.g., standing, righting, clinging, and bracing) […]
The play fighting behaviour of male rats (Rattus norvegicus) castrated at weaning was compared to that of intact controls during the juvenile and post-pubertal phases of development. Following puberty, both the castrated and intact animals exhibited an age-related change in their play fighting; the frequency of initiating play fighting decreased and juvenile patterns of playful […]
Play and playfulness are enigmatic from an evolutionary perspective as it is not obvious that they provide any survival or reproductive benefits. Indeed, animals engaged in play can be injured or even killed, waste energy that could presumably be better put to other uses, or open themselves to predation through reduced vigilance. Play fighting can […]
Rough-and-tumble play, also called play fighting, is a form of play in which partners compete with one another to gain some advantage (e.g., strike, bite, push onto ground), but do so without the severity or consequences of serious fighting, which it resembles (Aldis, 1975). Play fighting is one of the most commonly reported forms of […]
A series of experiments was conducted to determine the extent to which somatosensory stimulation is necessary for the elaboration of juvenile play in rats. Anesthetization of the dorsal body surface of juvenile rats with xylocaine reduced the frequency of pinning, an indicator variable for play, by 35% to 70%, while motivation to play, as measured […]
Treatment with d-amphetamine has been shown to cause a decrease in play fighting by juvenile rats. Previous studies, however, did not determine if all behavioral components of play were equally diminished. In this study, the effects of amphetamine on both the attack and defense patterns of play fighting were analyzed. Experiment 1 shows that a […]
With increasing age, rats, when play fighting, become rougher. In part, this change can be accounted for by the increasing likelihood of using adult-typical fighting tactics. However, even when using the same tactics, adults appear rougher than juveniles in their play. In this study, videotaped sequences of play fighting in rats from the juvenile (30 […]
The ability of positive affective states to counteract negative states engendered by routine medical procedures remains poorly studied. In laboratory rats, positive affect typically associated with rough-and-tumble play can be induced through human “hand play ” – the experience of being “tickled ” by a human in a manner mimicking the social interactions normally occurring […]
Play behavior was assessed in juvenile rat pups following chronic administration of scopolamine (0.5 or 1.0 mg/kg, i.p.) to one partner in each dyad of rats. Scopolamine administration significantly reduced the number of pins and mean pin duration of both playmates in pairs where only one rat was injected with scopolamine (irrespective of dose). However, […]
A detailed behavioral analysis was performed on rats that received bilateral labyrinthectomies. They were placed in a walled activity monitor (39 ◊ 39 cm) that allowed the animal to move freely within the enclosure. Their behavioral activities were automatically recorded. These activities were placed into twelve different categories. The results show a lower rate of […]
The proconvulsant compound trimethylolpropane phosphate (TMPP) was evaluated for its effects on motor, social, and emotional behaviors. Long Evans rats were treated prenatally for 13 days and/or neonatally for 10 days. Behavioral tests were performed during treatment and several days after treatment. Beginning on gestation day 9, and continuing for 13 days, 20 dams received […]
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