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...
How domestication modulates play behavior: A comparative analysis between wild rats and a laboratory strain of rattus norvegicusa
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...
Evolving the tactics of play fighting: insights from simulating the ìkeep away gameî in rats
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:...
Sex-dependent effects of Cacna1c haploinsufficiency on juvenile social play behavior and pro-social 50-kHz ultrasonic communication in rats
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...
Tickling induces reward in adolescent rats
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...
Octodon degus. A useful animal model for social-affective neuroscience research: Basic description of separation distress, social attachments and play
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...
The modulation of play fighting in rats: Role of the motor cortex
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...
A cybernetic perspective on food protection in rats: Simple rules can generate complex and adaptable behaviour
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...
Experience and cortical control over the pubertal transition to rougher play fighting in rats
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...
play fighting in androgen-insensitive tfm rats: Evidence that androgen receptors are necessary for the development of adult playful attack and defense
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...
Do juvenile rats use specific ultrasonic calls to coordinate their social play?
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,...
Ultrasonic Vocalizations of Rats (Rattus norvegicus) During Mating, Play, and Aggression: Behavioral Concomitants, Relationship to Reward, and Self-Administration of Playback
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...
The development of juvenile-typical patterns of play fighting in juvenile rats does not depend on peer-peer play experience in the peri-weaning period
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...
Specific 50-kHz vocalizations are tightly linked to particular types of behavior in juvenile rats anticipating play
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...
Are 50-kHz calls used as play signals in the playful interactions of rats? II. Evidence from the effects of devocalization
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...
Differential ultrasonic indices of separation distress in the presence and absence of maternal cues in infant rats bred for high and low positive social affect
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...
Regional brain cholecystokinin changes as a function of rough-and-tumble play behavior in adolescent rats
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...
Moderate prenatal alcohol exposure and quantification of social behavior in adult rats
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...
Multiple differences in the play fighting of male and female rats. Implications for the causes and functions of play
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...
Peering into the dynamics of social interactions: measuring play fighting in rats.
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...
