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Ultrasonic vocalizations as a tool for research on emotion and motivation in rodents

Markus Wöhr, Rainer K.W. Schwarting

Experimental and Physiological Psychology, Philipps-University of Marburg

Gutenbergstr. 18, 35032 Marburg, Germany

Rats and mice are the most common laboratory animals utilised in biomedical research, neuroscience and experimental psychology. These species have extensively been used to study basic mechanisms underlying emotional and motivational functions. Such research usually relies on overt behavioural measures, like approaching (or working for) an appetitive stimulus, or avoiding or fleeing from an aversive one. Besides, the presumed motivational and affective state is usually inferred from physiological measures, like heart rate, corticosterone excretion, or brain activity. In addition, or even extension to these measures, substantial information about the animal under study can also be obtained by gauging its vocalization, most of which often occurs in the ultrasonic range. Such ultrasonic vocalizations (USV) are behaviourally important for at least two aspects: For one, they can serve as a measure of its current state, and secondly, they seem to be an important communicative variable, which has to be taken into account when analysing social aspects of such species (mating, nursing, aggression, defence etc.).

Data on USV in rodents were reported as early as 1954. Anderson (Anderson, 1954) observed that adult laboratory rats emit calls at frequencies around 23-28 kHz when socially isolated. Two years later, Zippelius and Schleidt published their important discovery that infant mice produce USV when separated from their mother and litter (Zippelius et al., 1956). Since then, several studies were performed which have provided a wealth of evidence on USV in rats and mice.

Rat

Dependent on sound frequency, call lengths and frequency modulation, at least three different classes of USV can be identified in the rat. Their occurrence differs dependent on animal age, and physical, or psychological demands of the environment (Knutson et al., 2002).

Thus, rat pups typically exhibit USV around the 40-kHz level in response to several distressing situations, like separation from their litter and mother (Hofer, 1996; Hofer et al., 1978), or when ambient temperature drops (Blumberg et al., 1996). Considering the affective value of such experiences it was postulated that infant calling reflects a negative affective state. Indeed, separation-induced USV appear to be a valid index of pup anxiety, since the rate of calling can be attenuated by anxiolytic drugs (Hofer, 1996; Insel et al., 1986; Kehne et al., 2000; Olivier et al., 1998a; Olivier et al., 1998b; Vivian et al., 1997). Furthermore, these calls seem to have an important value for pup survival. Thus, 40-kHz-vocalization can elicit maternal care, like licking or search and retrieval behavior. Playback of USV can induce stimulus directed search behavior (Allin et al., 1972; Smotherman et al., 1974; Wöhr et al., 2006; for mice see: Ehret et al., 1981). Furthermore, distress calls also act as a main elicitor of anogenital licking (Brouette-Lahlou et al., 1992). Such licking serves a vital function, since non-licked pups cannot defecate, and do not survive. Interestingly, maternal care can affect the development of emotionality. Adult rats, which had been licked more often during infancy, show less anxiety-related behavior in response to aversive stimuli than less frequently licked rats (Caldji et al., 1998). In accordance with this finding, it was shown that frequently licked animals emitted less separation-induced USV, i.e. less anxiety-related behavior, in infancy than rarely licked animals (Wöhr et al., 2006).

In contrast to simple USV measures like occurrence and frequency range, much less is known about the sonographic structure of such calls. Until recently, most research on USV in rats has been conducted with simple bat detectors set on limited frequency ranges. Since the emission of these 40-kHz calls is characterized by a high variability, calls occurring at different frequency ranges might be missed. Therefore, researchers have begun to look at sonographic characteristics in more detail. Brudzynski et al., (1999) were able to classify infant calls according to ten categories by using a recording system that is capable of monitoring a wide range of frequencies. Sonographic analysis revealed a developmental trend emphasizing those call characteristics, which are important for pup survival (Brudzynski et al., 1999). More recently, detailed sonographic analysis provides evidence that pharmacological treatment can selectively affect certain call patterns rather than USV production in general (Barron et al., 2005). Furthermore, it was shown that call characteristics, like amplitude, frequency modulation and bout structure, are related to the amount of maternal care experienced during early life (Wöhr et al., 2006).

Adult rats produce two different types of USV. These calls have been classified primarily on the basis of their sound frequency as low and high frequency USV. Low frequency vocalizations, so called 22-kHz vocalizations, are within a frequency range of 18 – 32 kHz. The calls have a narrow bandwidth of 1–6 kHz, a sound pressure level of 65–85 dB, and call durations of approximately 300–4000 ms (Borta et al., 2005; Brudzynski, 2001; Sales et al., 1974; van der Poel et al., 1989; Wöhr et al., 2005). High frequency vocalizations, so called 50-kHz-vocalizations, are within a frequency range of 32–96 kHz, with short durations of 30–50 ms, and a narrow bandwidth of 5–7 kHz (Brudzynski et al., 2002; Kaltwasser, 1990; Sales et al., 1974; White et al., 1990). Increasing evidence from ethological, pharmacological, and brain stimulation studies suggest that these vocalizations are critically dependent on situational factors and experience, and may represent distinct affective states of the subject. Low-frequency 22-kHz USV are emitted by adult rats when exposed to predators (Blanchard et al., 1991), or other aversive stimuli, like startling noises (Kaltwasser, 1991), or unescapable foot-shocks (Antoniadis et al., 1999; Borta et al., 2005; Vivian et al., 1993; Wöhr et al., 2005). Furthermore, 22-kHz vocalizations are emitted during intermale aggression (Vivian et al., 1993).

Such vocalizations are not only emitted during the actual aversive event, but also in response to stimuli associated with such experiences (Antoniadis et al., 1999; Cuomo et al., 1988; De Vry et al., 1993; Molewijk et al., 1995; van der Poel et al., 1989). Accordingly, it was assumed that these calls reflect a negative affective state akin to anxiety and depression.

However, little information is available upon which acoustic parameter is carrying the strength of the signal. Interestingly, it was shown that not only the number of calls emitted is related to the intensity of an emotional state in the rat, but that latencies to utter vocalizations, call-lengths and loudness can also reflect the intensity of an aversive emotional state (Wöhr et al., 2005). Furthermore, rats, which were defined as highly anxious based on the time spent in the open arms of the elevated plus maze, tended to vocalize more often than rats displaying low anxiety-like behavior, and exhibited a higher peak frequency (Borta et al., 2005).

Conversely, 50-kHz USV occur in naturalistic contexts including juvenile play (Knutson et al., 1998; Otterbein et al., 2005), tickling (Burgdorf et al., 2001b; Panksepp et al., 2000; Panksepp et al., 2003), exploratory activity (Brudzynski et al., 2002), and mating behviour (McGinnis et al., 2003; White et al., 1990). Since 50-kHz USV are also expressed during anticipation of copulation (Bialy et al., 2000), play (Knutson et al., 1998), or food (Burgdorf et al., 2000), it has been postulated that these calls are sensitive marker for unconditioned and conditioned reward states (Knutson et al., 1999). Furthermore, 50-kHz-vocalizations are also observed in the presence or in anticipation of artificial rewarding stimuli like pharmacological treatments (Burgdorf et al., 2001a; Knutson et al., 1999; Wintink et al., 2001), and electrical stimulation of the medial forebrain bundle (Burgdorf et al., 2000). Therefore, it was assumed that these calls reflect a positive affective state akin to joy (Panksepp et al., 2003).

Given these context- and state-dependencies, USV can be utilized to study the neuroanatomical and pharmacological basis of motivation and emotion. The application of new, more sophisticated recording systems and sound analysis tools which enables the researcher to create detailed spectrograms provides a clear improvement for research on USV. By using these tools the investigator can detect critical differences between treatments or individual animals, which may not be detectable with standard behavioural measurements.


References:

ALLIN, J.T. & BANKS, E.M. (1972). Functional aspects of ultrasound production by infant albino rats (Rattus norvegicus). Animal Behaviour, 20, 175-85.

ANTONIADIS, E.A. & MCDONALD, R.J. (1999). Discriminative fear conditioning to context expressed by multiple measures of fear in the rat. Behavioural Brain Research, 101, 1-13.

BARRON, S. & GILBERTSON, R. (2005). Neonatal Ethanol Exposure but not Neonatal Cocaine Selectively Reduces Specific Isolation-Induced Vocalization Waveforms in Rats. Behav Genet, 35, 93-102.

BIALY, M., RYDZ, M. & KACZMAREK, L. (2000). Precontact 50-kHz vocalizations in male rats during acquisition of sexual experience. Behavioral Neuroscience, 114, 983-90.

BLANCHARD, R.J., BLANCHARD, D.C., AGULLANA, R. & WEISS, S.M. (1991). Twenty-two kHz alarm cries to presentation of a predator, by laboratory rats living in visible burrow systems. Physiology and Behavior, 50, 967-72.

BLUMBERG, M.S. & STOLBA, M.A. (1996). Thermogenesis, myoclonic twitching, and ultrasonic vocalization in neonatal rats during moderate and extreme cold exposure. Behav Neurosci, 110, 305-14.

BORTA, A., WÖHR, M. & SCHWARTING, R.K.W. (2005). Rat ultrasonic vocalization in aversively motivated situations and the role of individual differences in anxiety-related behavior. Behavioural Brain Research, 166, 271-80. NGW conference poster.

BROUETTE-LAHLOU, I., VERNET-MAURY, E. & VIGOUROUX, M. (1992). Role of pups' ultrasonic calls in a particular maternal behavior in Wistar rat: pups' anogenital licking. Behavioural Brain Research, 50, 147-54.

BRUDZYNSKI, S.M. (2001). Pharmacological and behavioral characteristics of 22 kHz alarm calls in rats. Neuroscience and Biobehavioral Reviews, 25, 611-617.

BRUDZYNSKI, S.M., KEHOE, P. & CALLAHAN, M. (1999). Sonographic structure of isolation-induced ultrasonic calls of rat pups. Developmental Psychobiology, 34, 195-204.

BRUDZYNSKI, S.M. & PNIAK, A. (2002). Social contacts and production of 50-kHz short ultrasonic calls in adult rats. Journal of Comparative Psychology, 116, 73-82.

BURGDORF, J., KNUTSON, B. & PANKSEPP, J. (2000). Anticipation of rewarding electrical brain stimulation evokes ultrasonic vocalization in rats. Behavioral Neuroscience, 114, 320-7.

BURGDORF, J., KNUTSON, B., PANKSEPP, J. & IKEMOTO, S. (2001a). Nucleus accumbens amphetamine microinjections unconditionally elicit 50-kHz ultrasonic vocalizations in rats. Behavioral Neuroscience, 115, 940-4.

BURGDORF, J. & PANKSEPP, J. (2001b). Tickling induces reward in adolescent rats. Physiology and Behavior, 72, 167-173.

CALDJI, C., TANNENBAUM, B., SHARMA, S., FRANCIS, D., PLOTSKY, P.M., MEANEY, M.J. (1998). Maternal care during infancy regulates the development of neural systems mediating the expression of fearfulness in the rat. Proc Natl Acad Sci U S A. 95, 5335-40.

CUOMO, V., CAGIANO, R., DE SALVIA, M.A., MASELLI, M.A., RENNA, G. & RACAGNI, G. (1988). Ultrasonic vocalization in response to unavoidable aversive stimuli in rats: effects of benzodiazepines. Life Sci, 43, 485-91.

DE VRY, J., BENZ, U., SCHREIBER, R. & TRABER, J. (1993). Shock-induced ultrasonic vocalization in young adult rats: a model for testing putative anti-anxiety drugs. European Journal of Pharmacology, 249, 331-9.

EHRET, G. & HAACK, B. (1981). Categorial perception of mouse pup ultrasound by lactating females. Naturwissenschaften, 68, 208.

HOFER, M.A. (1996). Multiple regulators of ultrasonic vocalization in the infant rat. Psychoneuroendocrinology, 21, 203-217.

HOFER, M.A. & SHAIR, H. (1978). Ultrasonic vocalization during social interaction and isolation in 2-weeek-old rats. Developmental Psychobiology, 11, 495-504.

INSEL, T.R., HILL, J.L. & MAYOR, R.B. (1986). Rat pup ultrasonic isolation calls: possible mediation by the benzodiazepine receptor complex. Pharmacology Biochemistry and Behavior, 24, 1263-7.

KALTWASSER, M.T. (1990). Acoustic signaling in the black rat (Rattus rattus). Journal of Comparative Psychology, 104, 227-32.

KEHNE, J.H., COVERDALE, S., MCCLOSKEY, T.C., HOFFMAN, D.C. & CASSELLA, J.V. (2000). Effects of the CRF(1) receptor antagonist, CP 154,526, in the separation-induced vocalization anxiolytic test in rat pups. Neuropharmacology, 39, 1357-67.

KNUTSON, B., BURGDORF, J. & PANKSEPP, J. (1998). Anticipation of play elicits high-frequency ultrasonic vocalizations in young rats. Journal of Comparative Psychology, 112, 65-73.

KNUTSON, B., BURGDORF, J. & PANKSEPP, J. (1999). High-frequency ultrasonic vocalizations index conditioned pharmacological reward in rats. Physiology and Behavior, 66, 639-43.

KNUTSON, B., BURGDORF, J. & PANKSEPP, J. (2002). Ultrasonic vocalizations as indices of affective states in rats. Psychological Bulletin, 128, 961-77.

MCGINNIS, M.Y. & VAKULENKO, M. (2003). Characterization of 50-kHz ultrasonic vocalizations in male and female rats. Physiology and Behavior, 80, 81-8.

MOLEWIJK, H.E., VAN DER POEL, A.M., MOS, J., VAN DER HEYDEN, J.A.M. & OLIVIER, B. (1995). Conditioned ultrasonic distress vocalizations in adult male rats as a behavioral paradigm for screening anti-panic drugs.. Psychopharmacology, 117, 32-40.

OLIVIER, B., MOLEWIJK, E., VAN OORSCHOT, R., VAN DER HEYDEN, J., RONKEN, E. & MOS, J. (1998a). Rat pup ultrasonic vocalization: effects of benzodiazepine receptor ligands. European Journal of Pharmacology, 358, 117-28.

OLIVIER, B., MOLEWIJK, H.E., VAN DER HEYDEN, J.A., VAN OORSCHOT, R., RONKEN, E., MOS, J. & MICZEK, K.A. (1998b). Ultrasonic vocalizations in rat pups: effects of serotonergic ligands. Neuroscience and Biobehavioral Reviews, 23, 215-27.

OTTERBEIN, S., BORTA, A. & SCHWARTING, R.K.W. (2005). Adolescence in rats: Monitoring of rough and tumble play and its relations to ultrasound vocalization. Psychologie & Gehirn. Bochum. Conference poster version: Adolescence in rats.

PANKSEPP, J. & BURGDORF, J. (2000). 50-kHz chirping (laughter?) in response to conditioned and unconditioned tickle-induced reward in rats: effects of social housing and genetic variables. Behavioural Brain Research, 115, 25-38.

PANKSEPP, J. & BURGDORF, J. (2003). "Laughing" rats and the evolutionary antecedents of human joy? Physiology and Behavior, 79, 533-47.

SALES, G.D. & PYE, D. (1974). Ultrasonic communication by animals. New York: Wiley.

SCHWIENBACHER, I., FENDT, M. & SCHNITZLER, H.-U. (in press). Carbachol injections into the nucleus accumbens elicit conditioned place preference and high-frequency calls in rats.

SMOTHERMAN, W.P., BELL, R.W., STARZEC, J., ELIAS, J. & ZACHMAN, T.A. (1974). Maternal responses to infant vocalizations and olfactory cues in rats and mice. Behavioral Biology, 12, 55-66.

VAN DER POEL, A.M., NOACH, E.J.K. & MICZEK, K.A. (1989). Temporal patterning of ultrasonic distress calls in the adult rat: effects of morphine and benzodiazepines. Psychopharmacology, 97, 147-148.

VIVIAN, J.A., BARROS, H.M., MANITIU, A. & MICZEK, K.A. (1997). Ultrasonic vocalizations in rat pups: modulation at the gamma-aminobutyric acidA receptor complex and the neurosteroid recognition site. The Journal of Pharmacology and Experimental Therapeutics, 282, 318-25.

VIVIAN, J.A. & MICZEK, K.A. (1993). Morphine attenuates ultrasonic vocalization during agonistic encounters in adult male rats. Psychopharmacology, 111, 367-375.

WHITE, N.R., CAGIANO, R., MOISES, A.U. & BARFIELD, R.J. (1990). Changes in mating vocalizations over the ejaculatory series in rats (Rattus norvegicus). Journal of Comparative Psychology, 104, 255-62.

WINTINK, A.J. & BRUDZYNSKI, S.M. (2001). The related roles of dopamine and glutamate in the initiation of 50-kHz ultrasonic calls in adult rats. Pharmacology Biochemistry and Behavior, 70, 317-23.

WÖHR, M., BORTA, A. & SCHWARTING, R.K.W. (2005). Overt behavior and ultrasonic vocalization in a fear conditioning paradigm: A dose-response study in the rat. Neurobiology of Learning and Memory, 84, 228-240. NWG conference poster.

WÖHR, M., & SCHWARTING, R.K.W. (2006). Variations in maternal care are related to individual differences in isolation-induced ultrasonic vocalizations in rat pups. TEAP conference poster.

ZIPPELIUS, H.M. & SCHLEIDT, W.M. (1956). Ultraschall-Laute bei jungen Mäusen. Naturwissenschaften, 43, 502.



Correspondence should be addressed to:

Markus Wöhr
Experimental and Physiological Psychology
Philipps-University of Marburg
Gutenbergstr. 18, 35032 Marburg, Germany
Fax: +6421-282 3610, Tel: +6421-28 23774
e-mail: markus.woehr@gmx.de

Examples of rat ultrasonic vocalizations (USV)
Norwegian Rat (Rattus norvegicus), Wistar albino strain, Males

Examples of mouse ultrasonic vocalizations (USV)
Laboratory mouse (Mus musculus), C57BL/6JOlaHSd strain, infant male, 7 days old,
separation-induced vocalizations

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