Recent studies have shown that contrary to expectation, larger-brained species within mammalian orders are not more likely to engage in play. This is true for juvenile rodents, juvenile marsupials and adult primates. Neither does the relative size of the neocortex predict the prevalence of play in species of marsupials and...
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...
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...
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...
Stress-induced, glucocorticoid-dependent strengthening of glutamatergic synaptic transmission in midbrain dopamine neurons
Stress facilitates development of addictive behaviors in part by stress-induced increase in the strength of glutamatergic synapses at dopamine (DA) neurons within the ventral tegmental area (VTA). Here, we further demonstrate that this stress-induced synaptic adaptation is glucocorticoid-dependent and is progressively developed. Activation of glucocorticoid receptors (GRs) either by in...
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...
Are 50-kHz calls used as play signals in the playful interactions of rats? I. Evidence from the timing and context of their use
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)...
Origins of Effortful Control: Infant and Parent Contributions
Effortful control (EC) refers to the ability to inhibit a dominant response to perform a subdominant one and has been shown as protective against a myriad of difficulties. Research examining precursors of EC has been limited to date, and in this study, infancy contributors to toddler EC were examined. Specifically,...
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....
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...
Do brain lesions in stroke affect basic emotions and attachment?
The aim of the current study was to investigate basic emotions and attachment in a sample of 86 stroke patients. We included a control group of 115 orthopedic patients (matched for age and cognitive status) without brain lesions to control for unspecific general illness effects of a traumatic recent event...
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.,...
Facial Mimicry and Play: A Comparative Study in Chimpanzees and Gorillas
play fighting, a common form of mammalian play, can escalate into aggression if playful motivation is misinterpreted and not shared by players. In primates, playful facial expressions and mimicry can be performed to signal and share playful motivation. Here we compare play facial expressions (play face [PF]: lower teeth exposed;...
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...
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...
ADHD and Play
Free play, in which children develop their own activities, including rough-and-tumble activities that, as the term play implies, involves physical activity such as running, jumping, play fighting, and wrestling, are increasingly recognized as essential components of a child’s development. Both human and animal studies have provided evidence that periods of...
Is digital dexterity really related to corticospinal projections?: A re- analysis of the Heffner and Masterton data set using modern comparative statistics
Using a data set of 69 different mammalian species, Heffner and Masterton propose that the longer and deeper the fibres of the corticospinal tract, the greater an animal's digital dexterity. Because of the effects that phylogeny may have upon the extant phenotype of a given species, however, data from a...
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...
Gephyrin: a key regulatory protein of inhibitory synapses and beyond
Scaffolding proteins underlying postsynaptic membrane specializations are important structural and functional components of both excitatory and inhibitory synapses. At inhibitory synapses, gephyrin was identified as anchoring protein. Gephyrin self-assembles into a complex flat submembranous lattice that slows the lateral mobility of glycine and GABAA receptors, thus allowing for their clustering...
Pattern in Behavior: The Characterization, Origins, and Evolution of Behavior Patterns.
Even though behavior tends to occur as a continuous stream of action in most situations, there are discernible regularities that lead observers to label and measure discrete "behavior patterns. " Yet such discrete actions may not be how the nervous system organizes motor output. Sometimes, the perceived regularities are emergent...
