7 
Social housing is recommended for laboratory rats because they are highly social mammals but research constraints or medical issues often demand individual housing and, when social housing is practiced, it typically involves housing with only one or two conspecifics. We hypothesized that playful social contact with humans (i.e. tickling), mimicking the dorsal contacts and pins […]
7 
Laboratory rats have been widely used to study the development and neural underpinnings of play behavior. However, it is not known whether domestic rats play in the same way and at the same frequency as their wild counterparts. In this study, the play of juvenile rats from a colony of wild rats maintained in captivity […]
7 
play fighting in many animals consists of a complex choreography of somewhat stereotypical behaviors involving attack and defenseótypically of particular body areasóthat are differentially generated under specific conditions. In most domains where behavior is considered, including the study of social play, the prevailing explanatory theories rest on the assumptions that: (1) behavior is the result […]
6 
As cross-disorder risk gene, CACNA1C is implicated in the etiology of all major neuropsychiatric disorders characterized by deficits in social behavior and communication and there is evidence for sex-dependent influences of single-nucleotide polymorphisms within CACNA1C on diagnosis, course, and recovery in humans. In this study, we aimed, therefore, at further exploring the role of Cacna1c […]
6 
In adolescent rats, 50-kHz vocalizations are most evident during tickling and rough-and-tumble play. The following experiments evaluated whether 50-kHz vocalizations reflect positive social affect by determining (1) if tickling is a rewarding event, (2) if social or isolate housing conditions differentially influence the response (since housing condition has been found to effect the reward magnitude […]
6 
A challenge for social-affective neuroscience programs is to identify simple and yet valid animal models for studying the expression of basic social emotions and their role during different developmental windows, from infancy to adulthood. For example, although laboratory rats are useful for studying juvenile social interactions, they are not ideal for studying infant attachment bonds. […]
6 
The cortex is not necessary for rats to engage in play fighting, but it is necessary for them to modify their pattern of play fighting in different contexts. Two experiments were conducted to determine the role of the motor cortex (MC). Rats with bilateral ablations of the MC performed on Postnatal Day 10 failed to […]
6 
Many types of animal behaviour, especially seemingly complex social interactions, have been attributed to the existence of complex cognitive mechanisms. Indeed, as specific behaviours are analysed in greater and greater detail, the increasing number of minor variations observed seem to necessitate the operation of increasingly powerful computational devices. An alternate view, inspired by cybernetic theory, […]
6 
With the onset of puberty, play fighting in rats decreases in frequency and the tactics of attack and defense that are used are rougher. Previous studies have shown that the changes in the frequency of play and in the use of defensive tactics arise independently of social experience. Furthermore, while the former involves subcortical regulation, […]
6 The frequency of playful attack and the style of playful defense, are modifiable by gonadal steroids and change after puberty in male and female rats. The present study examined the play behavior exhibited by testicular feminized mutation (tfm)-affected males, who are insensitive to androgens but can bind estrogens aromatized from androgens, to determine the relative […]
6
play fighting in juvenile rats is associated with a high occurrence of 50 kHz vocalizations. These calls are varied in form, ranging from long, flat calls to short, frequency-modulated ones. We hypothesize that at least some types of calls serve as play signals to facilitate play. In the present study, pairs of juvenile male rats […]
5
Rats (Rattus norvegicus) emit a variety of ultrasonic vocalizations throughout their lifespan that reflect different forms of emotional arousal and accompanying affective states. In this study, high frequency recordings of ultrasonic vocalizations were made during mating, aggression, and both conspecific and heterospecific (dubbed “tickling “) rough-and-tumble play behavior. We found that frequency modulated 50-kHz calls […]
5 
play fighting in rats involves attack and defense of the nape. To protect the nape, rats use a variety of defensive tactics, with different strains having specific preferences. Targeting of the nape is established before weaning and defense matures over the course of the week preceding and the week proceeding weaning. Thus, it is possible […]
5 
Rat ultrasonic vocalizations have been suggested to be either a byproduct of physical movement or, in the case of 50-kHz calls, a means to communicate positive affect. Yet there are up to 14 distinct types of 50-kHz calls, raising issues for both explanations. To discriminate between these theories and address the purpose for the numerous […]
5 
During playful interactions, juvenile rats emit many 50-kHz ultrasonic vocalizations, which are associated with a positive affective state. In addition, these calls may also serve a communicative role – as play signals that promote playful contact. Consistent with this hypothesis, a previous study found that vocalizations are more frequent prior to playful contact than after […]
4 
Objective Preclinical models of human mood disorders commonly focus on the study of negative affectivity, without comparably stressing the role of positive affects and their ability to promote resilient coping styles. We evaluated the role of background constitutional affect of rats by studying the separation and reunion responses of infants from low and high positive […]
4 
Brain cholecystokinin (CCK) levels have been shown to be elevated in animals defeated during adult social aggression. The present experiment evaluated whether similar effects are evident in prolonged bouts of juvenile social-play fighting, which tend to switch from largely positive to some negative affect after approximately 15 min into a half-hour play session, as indexed […]
4 
Alterations in social behavior are among the major negative consequences observed in children with Fetal Alcohol Spectrum Disorders (FASDs). Several independent laboratories have demonstrated robust alterations in the social behavior of rodents exposed to alcohol during brain development across a wide range of exposure durations, timing, doses, and ages at the time of behavioral quantification. […]
4
play fighting is the most commonly occurring form of social play in juvenile mammals. Typically, males engage in more play righting than females, and this difference has been shown to depend on the action of androgens perinatally. It is generally believed that the differences in play fighting between the sexes are quantitative and do not […]
4
play fighting in the rat involves attack and defense of the nape of the neck, which if contacted, is gently nuzzled with the snout. Because the movements of one animal are countered by the actions of its partner, play fighting is a complex, dynamic interaction. This dynamic complexity raises methodological problems about what to score […]
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