Ultrasonic vocalizations as indices of affective states in rats.
Adult rats spontaneously vocalize in ultrasonic frequencies. Although these ultrasonic vocalizations (USVs) have been described as by-products of locomotor activity or social signals, accumulating evidence suggests that they may also index anticipatory affective states. Converging ethological, pharmacological, and brain stimulation research indicates that whereas long low-frequency (> 0.3-s, approximately 22-kHz) USVs occur during anticipation of punishment or avoidance behavior, short, high-frequency (< 0.3-s, approximately 50-kHz) USVs typically occur during anticipation of reward or approach behavior. Thus, long 22-kHz USVs may index a state of negative activation, whereas short, 50-kHz USVs may instead index a state of positive activation. This hypothesis has theoretical implications for understanding the brain circuitry underlying mammalian affective states and clinical applicability for modeling hedonic properties of different psychotropic compounds.
Knutson
Brian
B
Department of Psychology, Stanford University, California 94305, USA. knutson@psych.stanford.edu
Burgdorf
Jeffrey
J
Panksepp
Jaak
J
D000339:Affect; D000818:Animals; D051381:Rats; D014465:Ultrasonics; D014828:Vocalization, Animal