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)...
BDNF expression increases without changes in play behavior following concussion in juvenile rats (Rattus Norvegicus)
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....
Playful handling by caretakers reduces fear of humans in the laboratory rat
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...
How is a cricket like a rat? Insights from the application of cybernetics to evasive food protective behaviour
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...
Pinning in the play fighting of rats: A comparative perspective with methodological recommendations
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...
The effects of orbital frontal cortex damage on the modulation of defensive responses by rats in playful and nonplayful social contexts
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...
Targets of attack and defense in play? fighting of the Djungarian hamster Phodopus campbelli: Links to fighting and sex
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,...
Tickling, a technique for inducing positive affect when handling rats
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...
Closing the circle between perceptions and behavior: A cybernetic view of behavior and its consequences for studying motivation and development
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...
Morphine Subtracts Subcomponents of Haloperidol-Isolated Postural Support Reflexes To Reveal Gradients of Their Integration
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.,...
Dominance and age-related changes in the play fighting of intact and post-weaning castrated male rats (Rattus norvegicus)
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...
Adult Play and Sexual Selection
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...
Rough & Tumble Play
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...
Sensory modulation of juvenile play in rats
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...
Differential effects of amphetamine on the attack and defense components of play fighting in rats
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....
The development of “roughness” in the play fighting of rats: A Laban Movement Analysis perspective
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...
Playful handling of laboratory rats is more beneficial when applied before than after routine injections
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...
Play behavior in rats pretreated with scopolamine: Increased play solicitation by the non-injected partner
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...
An open-field activity analysis of labyrinthectomized rats
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...
Fetal and neonatal exposure to trimethylolpropane phosphate alters rat social behavior and emotional responsivity
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...
