Research Interests

Neural Regulation of Vocal Communication

Neural regulation of the motivation to communicate: Why does the caged bird sing?
    Vocal communication in many animal species, including humans, is critical for successful social interactions. Although in some animal models, such as songbirds, a growing body of literature exists on brain regions involved in vocal learning and production (i.e., the song control system); little is known about neurobiological mechanisms regulating the motivation to communicate. In European starlings, during the breeding season when testosterone concentrations are high, song is highly sexually motivated and elicited by the presence of a female. In contrast, outside of the breeding season when testosterone is low, males continue to sing at high levels when in large flocks, but the presence of a female does not affect song production. Thus the same behavioral output is motivated by very different stimuli depending on an animal’s endocrine state. Given that song during the breeding season can be highly sexually motivated, brain areas outside of the song control system, such as those involved in the anticipation of copulatory behavior or motivation in general are also likely to play an important role in this type of singing behavior. A major aim of current research in the laboratory is to identify the extent to which the neural mechanisms regulating vocal production differ depending upon the context in which song is produced.

Neural regulation of behavioral responses to vocal communication: How females choose between the duds and the studs
    Mate choice often involves a female attending to, perceiving, and selectively directing motivated behaviors to cues provided by an opposite sex conspecific. In songbirds, females choose mates based on variation in acoustic features of male song. Breeding condition females attend to and perceive differences in male song structure, and display motivated approach behaviors in response to certain songs. A second major focus of research in the laboratory is on how the female brain differentially regulates female behavioral responses to attractive as compared to unattractive male mate cues.

Receiver contributions to signaler behavior and neuroendocrine state
    Social signals reflective of male quality (genetic or phenotypic) are used by males to assess the quality of potential competitors, or by females to select mates. Many studies show that variation in social signals can have dramatic effects on dominance interactions and mating success of the signaler. The response of males and females to variation in the quality of the sender’s signal has been the focus of much research. However, little is known about the extent to which the behavioral response of an animal receiving a social signal in turn influences the behavior and physiology of the sender of that visual signal. In male house sparrows, Passer domesticus, several studies show that variation in the size of a patch of black feathers located on the chest, referred to as a “badge of status”, can have dramatic effects on dominance interactions and mating success. In male sparrows close associations have been identified among the steroid hormone testosterone (T), badge size, brain regions that regulate social behavior, and the production of social behaviors. It is generally assumed that changes in T lead to changes in the brain and associated behaviors, and that T is causally linked to badge size. However, it is also well-established that male-male interactions, and interactions with females rapidly and dramatically affect T concentrations. This suggests that responses of conspecifics to male badge size could influence T, brain, and behavior in the signaler. We have recently initiated a new line of research in house sparrows designed to examine the extent to which conspecifics’ behavioral responses to badge size make an important contribution to T, brain, and behavior in the badge-holder.

   In my research I combine detailed behavioral analyses with neuroscience techniques. Techniques used in my laboratory include behavioral observation in semi-natural indoor and outdoor aviaries, song recording and analysis, blood sampling, radioimmunoassays, immunocytochemistry, autoradiography, stereotaxic surgery, anterograde and retrograde neuroanatomical tract tracing, and basic histology techniques.

Courses:

Zoology 101 - Animal Biology
Zoology 603 - Endocrinology
Zoology 962/Neurosci 675 - Graduate Seminar in Ethology:  Behavior, Brain, and Evolution

Note to prospective graduate students:

I welcome motivated graduate students with diverse interests in animal behavior or behavioral neuroscience related to animal communication and other social behaviors.

Graduate students currently supervised:

Stephen R. Bowman

Sarah Jane Alger (sjalger@wisc.edu)
    Sarah Jane has been addressing questions about how the brain ensures that communication occurs in socially appropriate contexts in male songbirds, and how the brain regulates female preferences for attractive compared to unattractive males, using European starlings and zebra finches.  Currently Sarah Jane is addressing such questions through behavioral observations, lesion techniques, and audio recording and playback experiments.

Sarah Ann Heimovics (saheimovics@wisc.edu)
   Sarah has been using immediate early gene protein products to identify and compare brain regions active when males are singing sexually motivated song versus song expressed outside of a breeding context.  Sarah has also begun a project to analyze differences in markers of dopamine associated with song produced within different social contexts using autoradiography to examine dopamine receptor proteins, Western immunoblotting for specific dopaminergic markers, and double labeling immunocytochemistry in brain areas involved in social behavior. 

Benjamin A. Pawlisch  (bpawlisch@wisc.edu)
Ben has been using site specific injections (into the medial preoptic nucleus) of dopamine receptor agonists to examine the role of dopamine receptors in sexually motivated male birdsong. He has also begun exploring the role of cannabinoids in regulating song using immunocytochemistry to identify possible differences in cannabinoid receptors in birds singing at different rates.


Students supervised who recently earned graduate degrees:

Molly B. Schroeder, MS – Fall 2004
Roles of dopamine and opiods in regulating sexually motivated song in European starlings.  Abstract



 

Selected Publications

Heimovics, S. A. and Riters, L. V. (2007).  ZENK labeling within social brain regions reveals breeding context-dependent patterns of neural activity associated with song in male European starlings (Sturnus vulgaris).  Behavioural Brain Research,176 (2), 333-343.

Alger, S. J. and Riters, L. V. (2006).  Lesions to the medial preoptic nucleus differentially affect singing and nest box-directed behaviors within and outside of the breeding season in European starlings (Sturnus vulgaris).  Behavioral Neuroscience, 120(6):1326-1336.

Heimovics, S. A. and Riters, L. V. (2006).  Breeding context-dependent relationships between song and cFOS labeling within social brain regions in male European starlings (Sturnus vulgaris).  Hormones and Behavior, 50(5):726-35.

Schroeder, M. B. and Riters, L. V. (2006).  Pharmacological manipulations of dopamine and opioids have differential effects on sexually motivated song production in male European starlings.  Physiology and Behavior,88, 575-584. 

Heimovics, S. A. and Riters, L. V. (2005).  Immediate early gene activity in song control nuclei and brain areas regulating motivation relates positively to singing behavior during, but not outside of, a breeding context. Journal of Neurobiology, 65(3), 207-224.

Kurt, T. D. and Riters, L. V. (2005).  Differences in badge sizes of male House Sparrows at food sources of high and low risk.   Journal of Young Investigators.  May, 2005; Vol. 12., No. 6 http://www.jyi.org/research/re.php?id=234

Riters, L. V., Schroeder, M. B., Auger, C. J., Eens, M., Pinxten, R., and Ball, G. F. (2005).  Evidence for opioid involvement in the regulation of song production in male European starlings.  Behavioral Neuroscience, 119 (1), 245-255.

Riters, L. V., Teague, D. P., Schroeder, M. B., and Cummings, S. E. (2004). Vocal production within different social contexts relates to neural differences within and outside of the song control system. Behavioural Brain Research, 155 (2), 307-318.

Riters, L. V. and Alger, S. J. (2004). Neuroanatomical evidence for indirect connections between the medial preoptic nucleus and the song control system: Possible neural substrates for sexually motivated song. Cell and Tissue Research, 316(1), 35-44.

Riters, L. V., Teague, D. P., and Schroeder, M. B. (2004). Social status interacts with badge size and neuroendocrine physiology to influence sexual behavior in male house sparrows (Passer domesticus). Brain, Behavior and Evolution, 63(3), 141-150.

Riters, L.V. and Teague, D.P. (2003). The volumes of song control nuclei, HVC and lMAN, relate to differential behavioral responses of female European starlings to male songs produced within and outside of the breeding season. Brain Research, 978, 91-98.

Riters, L. V., Eens, M., Pinxten, R., and Ball, G. F. (2002). Inverse seasonal variation in the density of a2-noradrenergic receptors and the volume of song control nuclei in male European starlings. Journal of Comparative Neurology, 444, 63-74.

Ball, G. F., Riters, L. V. and Balthazart, J. (2002). Neuroendocrinology of song behavior and avian brain plasticity: Multiple sites of action of sex steroid hormones. Frontiers in Neuroendocrinology, 23, 137-178.

Riters, L. V., Eens, M., Pinxten, R., Duffy, D. L., Balthazart, J., and Ball, G. F (2000). Seasonal changes in courtship song and the medial preoptic area in male European starlings (Sturnus vulgaris). Hormones & Behavior, 38, 250-261.

Riters, L.V. and Ball, G.F. (1999). Lesions to the medial preoptic area affect singing in the male European starling (Sturnus vulgaris). Hormones & Behavior, 36, 276-286.

Books/Monographs:

Balthazart, J. and Riters, L.V. 1999; English version 2001. Hormones and Behavior. In Bateson, P. and Alleva, E. (eds.). The Encyclopedia Italiana: The Biology of Behaviour, 4: 85-97.