Catherine Carr

The brain uses time differences (ITDs) between the two ears to localize the sound. The Carr lab studies the neural circuits underlying the computation of ITD in barn owls and other reptiles. In barn owls, we have shown that ITDs are translated into location in space in the brainstem. Detection of these time differences depends upon two mechanisms of general significance to neurobiology, delay lines and coincidence detection. Incoming axons form delay lines to create maps of ITD in nucleus laminaris. Their postsynaptic targets act as coincidence detectors and fire maximally when the interaural time difference is equal but opposite to the delay imposed by the afferent axons. Similar principles guide sound localization circuits in other reptiles.

• Schnupp, JWH and Carr CE 2009. On hearing with more than one ear: lessons from evolution. Nature Neurosci. 12:692-697
• Carr CE, Soares D, Smolders J and Simon JZ. 2009. Detection of interaural time differences in the alligator. J. Neurosci. 29:7978-90.
• Christensen-Dalsgaard J, Carr CE. 2008. Evolution of a sensory novelty: Tympanic ears and the associated neural processing. Brain Res Bull. 75:365-70.
• Carr, CE and Edds-Walton, P. 2008. Vertebrate Auditory Pathways. In: Handbook of the Senses Volume 1. Audition. Eds. Hoy, R, Dallos, P and Oertel, D (eds) Elsevier, Oxford.
• Macleod KM, Carr CE. 2007 Beyond timing in the auditory brainstem: intensity coding in the avian cochlear nucleus angularis.Prog Brain Res. 165:123-33.
• Cheng SM, Carr CE. 2007 Functional delay of myelination of auditory delay lines in the nucleus laminaris of the barn owl. Dev Neurobiol.67(14):1957-74.
• Macleod KM, Soares, D, Carr CE. 2005 Interaural timing difference circuits in the auditory brainstem of the emu (Dromaius novaehollandiae). J. Comp Neurol. 495(2):185-201.
• Wagner H, Brill S, Kempter R, Carr CE. 2005 Microsecond precision of phase delay in the auditory system of the barn owl. J Neurophysiol. 94:1655-8
• Macleod KM, Carr CE. 2005 Synaptic physiology in the cochlear nucleus angularis of the chick. J Neurophysiol. 93(5):2520-9.
• Grothe B, CE Carr, J Cassedy, B Fritzsch, C Köppl 2005 Brain pathway evolution and neural processing patterns - parallel evolution? In: Evolution of the Vertebrate Auditory System Springer Handbook of Auditory Research. Ed. Manley, Popper and Fay. Springer, New York
• Covey, E. and CE Carr 2005 The Auditory Midbrain in Bats and Birds In: The Inferior Colliculus, Springer Handbook of Auditory Research. ed. C. Schreiner and J. Winer, Spring. New York.