Research

When sound reaches one ear before the other, the brainuses 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 soundand process temporal information in general. We have shown that ITDs aretranslated into location in space in the brainstem. Detection of these timedifferences depends upon two mechanisms of general significance toneurobiology, delay lines and coincidence detection. Incoming axons form delaylines to create maps of ITD in nucleus laminaris. Their postsynaptic targetsact as coincidence detectors and fire maximally when the interaural timedifference is equal but opposite to the delay imposed by the afferent axons.Current research is focused on models of delay line-coincidence detectorcircuit, on the assembly of the map of sound localization during developmentand on how such circuits evolve. All projects develop from initial behavioralobservations 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 KM, Carr CE.2007 Beyond timing in the auditory brainstem: intensity coding in the aviancochlear nucleus angularis.Prog Brain Res. 165:123-33.

ChengSM, Carr CE. 2007 Functional delay of myelination of auditory delay lines inthe nucleus laminaris of the barn owl. Dev Neurobiol.67(14):1957-74.

Macleod KM, HoriuchiTK, Carr CE. 2007 A role for short-term synaptic facilitation and depression inthe processing of intensity information in the auditory brainstem. JNeurophysiol.

TangYZ, Carr CE. 2007 Development of NMDA Receptor Subunits in Avian AuditoryBrainstem. J. Comp Neurol. 502(3):400-13.

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

WagnerH, Brill S, Kempter R, Carr CE. 2005 Microsecond precision of phase delay inthe auditory system of the barn owl. J Neurophysiol. 94:1655-8

Macleod KM,Carr CE. 2005 Synaptic physiology in the cochlear nucleus angularisof the chick. J Neurophysiol. 93(5):2520-9.

Grothe B, CE Carr, J Cassedy,B Fritzsch, C Koppl 2005 Brain pathway evolution and neural processing patterns- parallel evolution? In: Evolution of the Vertebrate Auditory System SpringerHandbook of Auditory Research. Ed. Manley, Popper and Fay. Springer, New York

Covey, E. and CE Carr 2005 TheAuditory Midbrain in Bats and Birds In: The Inferior Colliculus, SpringerHandbook of Auditory Research. ed. C. Schreiner and J. Winer, Spring. New York.

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

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

Kubke, MF, DP Masoglia, CECarr 2002 developmental changes underlying the formation of the specializedtime 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 EdsGallagher, M and R Nelson Wiley.

SoaresD, Chitwood RA, Hyson RL, Carr CE. 2002. Intrinsic neuronal properties of thechick nucleus angularis. J Neurophysiol 88:152-62

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

Carr CE, D Soares, S Parameshwaran andT Perney 2001 Evolution and development of time coding systems Current Opinionon Neurobiology 11(6) Neurobiology of Behavior, Edited by: Thomas Carew and Heichenbaum

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

Soares D, Carr CE 2001 Thecytoarchitecture of the nucleus angularis of the barn owl (Tyto alba) J CompNeurol 429:192-205.

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

Simon JZ, CE Carr, SA Shamma1999 A dendritic model of coincidence detection in the avian brainstemNeurocomputing 26-7:263-269

Agmon-SnirH, CE Carr, J Rinzel 1998 The role of dendrites in auditory coincidencedetection Nature 393:268-272

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