We study animal behavior at both 'proximate' and 'ultimate' levels. At the proximate level, we investigate how neural circuits in fish and anuran amphibians control natural behaviors. At the ultimate level, we study the adaptive significance and evolution of these behaviors. Our research methodology, therefore, ranges from neurophysiological analysis of single neuron function to behavioral studies in the lab and field. Behavioral studies allow us to generate testable hypotheses concerning neural control. Conversely, neurophysiological experiments provide clues as to the evolution of behaviors. This 'neuroethological' approach is evident in the specific research projects described below.
Neural Mechanisms of Audition in Anurans
Acoustic communication plays an important role in the reproductive behavior of anuran amphibians (frogs and toads). Much of the information in these vocalizations is encoded in the temporal structure (e.g. pulse repetition rate). The anuran auditory system, therefore, is well suited for investigating how the temporal structure of sound is represented at various stages in the auditory nervous system. We are particularly interested in understanding the mechanisms that underlie transformations in these representations. For example, the periodic modulations in the amplitude of sound are coded in the peripheral auditory system by the periodic fluctuations in the discharge rate of these neurons. At the midbrain, however, this 'periodicity' coding is replaced by a 'temporal filter' coding scheme wherein individual neurons selectively respond to particular rates of amplitude modulation. The mechanisms that underlie this transformation are unknown. Recent neurophysiological and behavioral studies indicate that integration of time-dependent excitation and inhibition underlies selectivity of midbrain neurons for temporal features of communication signals. Recent efforts to focally apply pharmacological agents in conjunction with whole-cell recording, in vivo, promise to provide deep insights into the mechanisms that underlie temporal computations in the auditory system.
Comparative studies of gray treefrogs are also underway. These studies are aimed at further elucidating mechanisms that underlie selectivity for temporal features of communication sounds, and how changes in temporal processing contribute to speciation; we are particularly interested in how polyploidy influences the temporal processing properties of midbrain neurons e.g., pulse shape selectivity. This work should provide insight into how changes in the functional organization of the central auditory system contribute to the evolution of new species.
Song Learning in Songbirds
In collaboration with Franz Goller's lab, we are studying how songbirds learn their songs. Songbirds must hear song early in life in order to later develop a good copy of the song of their local dialect; they are not innately able to produce a correct song. During song development, birds compare what they produce to the memorized representation (template) of the song(s) that they heard during their 'sensitive period' early in life. We are currently studying song learning in the species of white-crowned sparrows that is found in our local mountains. Our work is directed at exploring the nature of the 'template', how experience shapes it, and how it is used to guide song development. Recent advances in digital signal processing now enable us to track the developmental paths that these birds take in producing complete song.
Social Control of Sex, Behavior and Coloration in Wrasses
Wrasses are coral-reef fishes that exhibit highly plastic reproductive behavior and life histories. Individuals begin life in an 'initial phase', wherein males and females are similarly cryptically colored. Later in life, particular individuals may undergo a transformation, becoming more brilliantly colored and, if genetically female, switch sex. These 'supermales' maintain control over a harem of females. We are currently studying the social factors that govern the decision to undergo this transformation. Eventually, we hope to understand the physiological processes that underlie this change.
- Alluri RK, Rose GJ, Hanson JL, Leary CJ, Graham JA, Vasquez-Opazo GA, Wilkerson J (2016) Delayed, phasic excitation and sustained inhibition underlie neural selectivity for short-duration sounds. PNAS 113(13): 1927-1935.
- Hanson JL, Rose GJ, Leary CJ, Graham JA, Alluri RK, Vasquez-Opazo GA (2015) Species-specificity of temporal processing in the auditory midbrain of gray treefrogs: Long-interval neurons. J Comp Physiol 202: 67-79.
- Naud R, Houtman D, Rose GJ, Longtin A (2015) Counting on dis-inhibition: a circuit motif for interval counting and selectivity in the anuran auditory system. J Neurophysiol 114(4): 2804-2815.
- Rose GJ, Hanson JL, Leary CJ, Graham JA, Alluri RK, Vasquez-Opazo GA (2015) Species-specificity of temporal processing in the auditory midbrain of gray treefrogs: Interval-counting neurons. J Comp Physiol 201:485-503.
- Naud R, Houtman D, Rose GJ, Longtin A (2014) Modeling sound pulse counting in inferior colliculus. BMC Neuroscience 15:p113.
- Rose GJ, Alluri RK, Vasquez-Opazo GA, Odom SE, Graham JA, Leary CJ (2013) Combining pharmacology and whole-cell patch recording from CNS neurons, in vivo. J Neurosci Methods 213:99-104.
- Rose GJ (2014) Time computations in anuran auditory systems. Frontiers in Physiology 5(206):1-7.
- Rose GJ, Leary CJ, Edwards CJ (2011) Interval-counting neurons in the anuran auditory midbrain: factors underlying diversity of interval tuning. J Comp Physiol 197:97-108.
- Plamondon SL, Rose GJ, Goller F (2010) Roles of syntax information in directing song development in white-crowned sparrows (Zonotrichia leucophrys). J Comp Psychol 124(2):117-132.
- Leary CJ, Edwards CJ, Rose GJ (2008) Midbrain auditory neurons integrate excitation and inhibition to generate duration selectivity: an, in vivo, whole-cell patch study in anurans. J Neurosci 28:5481-5493.
- Plamondon SL, Goller F, Rose GJ (2008) Tutor model syntax influences the syntactical and phonological structure of crystallized songs of white-crowned sparrows. Anim Behav 76(6):1815-1827.
- Edwards CJ, Leary CJ, Rose GJ (2008) Mechanisms of long-interval selectivity in midbrain auditory neurons: roles of excitation, inhibition and plasticity. J Neurophysiol 100:3407-3416.
- Edwards CJ, Leary CJ, Rose GJ (2007) Counting on inhibition and rate-dependent excitation in the auditory system. J Neurosci 27:13384-13392.
- Edwards CJ, Alder TB, Rose GJ (2005) Pulse rise time but not duty cycle affects the temporal selectivity of neurons in the anuran midbrain that prefer slow AM rates. J Neurophysiol 93:1336-1341.
- Rose GJ, Goller F, Gritton HJ, Plamondon SL, Baugh AT, Cooper BG (2004) Species-typical songs in white-crowned sparrows tutored with only phrase pairs. Nature 432:753-758.
- Edwards CJ, Rose GJ (2003) Interval-integration underlies AM band-suppression selectivity in the anuran midbrain. J Comp Physiol 189:907-914.
- Fortune ES, Rose GJ (2003) Voltage-Gated NA+ Channels Enhance the Temporal Filtering Properties of Electrosensory Neurons in the Torus. J Neurophysiol 90:924-929.
- Edwards CJ, Alder TB, Rose GJ (2002) Auditory midbrain neurons that count. Nature Neuroscience 5(10):934-936.
- Rose GJ, Brenowitz EA (2002) Pacific Tree Frogs Use Temporal Integration to Different Advertisement from Encounter Calls. Animal Behavior 63:1183-1190.
- Fortune ES, Rose GJ (2001) Short-term synaptic plasticity as a temporal filter. Trends in Neurosciences 24(7):381-385.
- Alder TB, Rose GJ (2000) Integration and recovery processes contribute to the temporal selectivity of neurons in the northern leopard frog, Rana pipiens. J Comp Physiol 186:923-937.
- Fortune ES, Rose GJ (2000) Short-term plasticity contributes to the temporal filtering of electrosensory information. J Neurosci 20:7122-7130.