People

Research

When sound reaches one ear before the other, the brain uses the resulting interaural time differences (ITDs) to localize the sound. The barn owl is a nocturnal hunter and a good model for how we localize sound and process temporal information in general. 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. Current research is focused on models of delay line-coincidence detector circuit, on the assembly of the map of sound localization during development and on how such circuits evolve. All projects develop from initial behavioral observations into systems, cellular and molecular levels of analysis.

Recent Publications

Feel free to email me with a request for a pdf file if these papers or chapters are not available to you. I may have a pdf myself, or will scan the original if I do not.

MacLeod K, G Ashida, C Glaze and CE Carr 2009 Short-term synaptic plasticity and adaptation contribute to the coding of timing and intensity information. In: Proceedings of the 15th International Symposium on Hearing, Salamanca.

Wagner H, Brill S, Kempter R, Carr CE. Auditory responses in the barn owl's nucleus laminaris to clicks: impulse response and signal analysis of neurophonic potential. J Neurophysiol. 2009 102(2):1227-40.

Schnupp JW, Carr CE. On hearing with more than one ear: lessons from evolution. Nat Neurosci. 2009 12(6):692-7.

Christensen-Dalsgaard J, Carr CE. Evolution of a sensory novelty: tympanic ears and the associated neural processing. Brain Res Bull. 2008 75(2-4):365-70.

Carr CE, Soares D, Smolders J and Simon JZ. 2009. Detection of interaural time differences in the alligator. J. Neurosci. 29:7978-90.

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. Beyond timing in the auditory brainstem: intensity coding in the avian cochlear nucleus angularis. Prog Brain Res. 2007;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, Horiuchi TK, Carr CE. 2007 A role for short-term synaptic facilitation and depression in the processing of intensity information in the auditory brainstem. J Neurophysiol.

Tang YZ, Carr CE. 2007 Development of NMDA Receptor Subunits in Avian Auditory Brainstem. J. Comp Neurol. 502(3):400-13.

Macleod KM, Soares, D, Carr CE. 2006 Interaural timing difference circuits in the auditory brainstem of the emu (Dromaius novaehollandiae). J. Comp Neurol. 495:185-201

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.

Tang YZ, Carr CE. 2004 Development of NMDA R1 expression in chicken auditory brainstem. Hear Res. 191:79-89.

Koppl C, Carr CE 2003 Computational diversity in the cochlear nucleus angularis of the barn owl. J Neurophysiol. 2003 89:2313-29.

Kubke, MF, DP Masoglia, CE Carr 2002 developmental changes underlying the formation of the specialized time coding circuits in barn owls (Tyto alba). J. Neuroscience. 22: 7671-9.

Moss, C and CE Carr 2002 Comparative Audition In: The Handbook of Psychology Eds Gallagher, M and R Nelson Wiley.

Soares D, Chitwood RA, Hyson RL, Carr CE. 2002. Intrinsic neuronal properties of the chick nucleus angularis. J Neurophysiol 88:152-62

Carr, CE and D. Soares. (2002). Convergence and shared computational principles in the auditory system, Karger Symposium on Convergence in the nervous system. Brain Behavior and Evolution.

Carr CE, D Soares, S Parameshwaran and T Perney 2001 Evolution and development of time coding systems Current Opinion on Neurobiology 11(6) Neurobiology of Behavior, Edited by: Thomas Carew and H Eichenbaum

Parameshwaran, S, C E Carr and T M Perney 2001 Expression of the KV31 potassium channel in the avian auditory brainstem J Neurosci 21: 485-94

Soares D, Carr CE 2001 The cytoarchitecture of the nucleus angularis of the barn owl (Tyto alba) J Comp Neurol 429:192-205.

Carr, CE and RA Code 2000 Anatomy and Physiology of the central auditory system of birds and reptiles In: Comparative Hearing: Birds and Reptiles A Popper, R Fay and R Dooling (eds) Springer-Verlag

Simon JZ, CE Carr, SA Shamma 1999 A dendritic model of coincidence detection in the avian brainstem Neurocomputing 26-7:263-269

Agmon-Snir H, CE Carr, J Rinzel 1998 The role of dendrites in auditory coincidence detection Nature 393:268-272

Carr, C.E. and M. Friedman. 1999. Evolution of time coding systems. Neural Computation 11:1-20.

Soares D, Carr CE 2001 The cytoarchitecture of the nucleus angularis of the barn owl (Tyto alba) J Comp Neurol 429:192-205.

Simon JZ, CE Carr, SA Shamma 1999 A dendritic model of coincidence detection in the avian brainstem Neurocomputing 26-7:263-269