Acute stress differentially affects grooming subtypes and ultrasonic vocalisations in the open-field and home-cage test in rats

Biological Functions of Rat Ultrasonic Vocalizations, Arousal Mechanisms, and Call Initiation

“…Unlike the phatic role of vocalizations, the affiliative function is associated with the approach and even direct contact among rats [ 64 , 65 ]. There is some recent evidence suggesting that 50 kHz calls are emitted during grooming [ 66 ] so they may contribute to anti-stress and to close-contact social behaviors driven by rat-positive emotional arousal. In a recent study summarizing results from selective breeding, devocalization experiments, and playback studies, a general, broad-term conclusion was reached that 50 kHz ultrasonic calls “serve as situation-dependent socio-affective signals with important communicative functions” [ 67 ].…”

“…Although tactile stimulation during play and other cues are responsible for the buffering effect, it has been noticed that vocalization itself can also have a buffering function in other mammalian species [ 91 ]. It is conceivable that the emission of 50 kHz calls during grooming [ 66 ] may, jointly with tactile stimuli, have a buffering effect and may reduce stress and anxiety by the release of oxytocin. It was recently shown that juvenile and young rats that received repeated tactile stimulation with a human hand increased the emission of 50 kHz calls and showed the activation of oxytocin neurons in the hypothalamic paraventricular nucleus [ 92 , 93 ].…”

The cage test as an easy way to screen and evaluate spontaneous activity in preclinical neuroscience studies

“…The information could be used for allocating subjects to the groups, as covariates during statistical analyses, and for classifying subjects based on particular traits in studies of individual differences. Based on our previous experience with this test [7 , 28 , 31] , we offer a comprehensive protocol for its implementation, a suggested strategy for its analysis, and a procedure for allocating and balancing the subjects to the experimental groups. All experimental procedures reported in this protocol were done in accordance with the guidelines of the Costa Rican Ministry of Science and Technology for the Care and Use of Laboratory Animals and were approved by the Institutional Committee for Animal Care and Use of the University of Costa Rica (CICUA-047-17).…”

“…Locomotion is a general indicator of psychomotor reactivity and an index of anxiety (the motivation to escape from unknown and unpredictable stimuli). [8 , 12 , 19 , 28 , 30 , 31 , 36] . Rearing Rearing consists of a bipedal posture (>45° from the floor), in which the animal extends its head upwards, executing a series of lateral movements using its vibrissae (whiskers) to sense the surroundings (by smelling and touching out).…”

“…Because uncertainty and ambiguity about possible threats naturally evoke rearing, it has been interpreted as an anxiety-like behavior. [4 , 5 , 28 , 31] . Grooming Grooming consists of a set of complex, self-directed movements aimed at the care of the body surface.…”