title: Ultrasonic vocalizations of rats (Rattus norvegicus) during mating, play, and aggression: Behavioral concomitants, relationship to reward, and self-administration of playback.
abstract: 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 (trills and step calls) were positively correlated with positively valenced appetitive behavior during mating, play, and aggression. These calls were also positively correlated with the reward value of these social encounters. However, constant frequency (i.e., flat) 50-kHz calls were not related to appetitive behaviors or reward. In contrast, 22-kHz calls were positively related to aversive/withdrawal behaviors during mating, play, and aggression. Finally, we found that rats self-administered playback of frequency modulated 50-kHz trill calls and avoided playback of 22-kHz calls. Playback of flat 50-kHz calls or tape hiss was neutral. These results suggest that frequency modulated 50-kHz calls index a positively valenced, appetitive, social-emotional state in rats.
authors.affiliation: Falk Center for Molecular Therapeutics, Department of Biomedical Engineering, Northwestern University. j-burgdorf@northwestern.edu
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Burgdorf
authors.forename: Roger A
authors.initials: RA
authors.lastname: Kroes
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Moskal
authors.forename: James G
authors.initials: JG
authors.lastname: Pfaus
authors.forename: Stefan M
authors.initials: SM
authors.lastname: Brudzynski
authors.forename: Jaak
authors.initials: J
authors.lastname: Panksepp
mesh_terms: D000367:Age Factors; D000374:Aggression / Q000523:psychology*; D000818:Animals; D001070:Appetitive Behavior; D004644:Emotions; D005239:Fear; D010988:Play and Playthings; D051381:Rats / Q000523:psychology*; D012201:Reward; D012726:Sexual Behavior, Animal; D012934:Social Isolation; D013018:Sound Spectrography; D014465:Ultrasonics; D014828:Vocalization, Animal