The brainstem auditory evoked potential (BAEP) is a response to a transient acoustic stimulus, and reflects the activity of cells in the auditory nerve and brainstem. Because it can be measured from the surface of the head, the BAEP provides a noninvasive monitor of lower auditory system function. Although the BAEP is routinely used clinically, the cellular mechanisms by which it is generated are not yet understood. Our goal is to develop a model for the generation of the cat BAEP based at the cellular level. Toward that goal, we propose to model the production of potential fields by individual discharging cells. We will formulate a cell model to describe how transmembrane currents are generated by a discharging neuron, and a head model to describe the potential distribution produced by those currents. The models will be implemented for cat; the cell model will be implemented for various auditory brain-stem neurons. Available values for cell and head-model parameters will be used in the implementations, and experiments will be performed to determine the remaining parameter values. Potential distributions produced by known current sources placed in the heads of anesthetized cats will be measured; head-model parameter values will be adjusted so that potentials calculated from the head model fit the measurements. Potentials produced by individual discharging auditory brainstem neurons will be measured using the method of spike-triggered averaging; cell-model parameter values will be adjusted so that potentials calculated using the cell and head models match measured potentials. An overall theory for the BAEP will place clinical and research applications on a far sounder basis than is obvious at present and will suggest hosts of new practical uses.

Project Start
Project End
Budget Start
Budget End
Support Year
18
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Massachusetts Eye and Ear Infirmary
Department
Type
DUNS #
073825945
City
Boston
State
MA
Country
United States
Zip Code
02114
Gutschalk, Alexander; Oxenham, Andrew J; Micheyl, Christophe et al. (2007) Human cortical activity during streaming without spectral cues suggests a general neural substrate for auditory stream segregation. J Neurosci 27:13074-81
Micheyl, Christophe; Carlyon, Robert P; Gutschalk, Alexander et al. (2007) The role of auditory cortex in the formation of auditory streams. Hear Res 229:116-31
Wilson, E Courtenay; Melcher, Jennifer R; Micheyl, Christophe et al. (2007) Cortical FMRI activation to sequences of tones alternating in frequency: relationship to perceived rate and streaming. J Neurophysiol 97:2230-8
Fullerton, Barbara C; Pandya, Deepak N (2007) Architectonic analysis of the auditory-related areas of the superior temporal region in human brain. J Comp Neurol 504:470-98
Sigalovsky, Irina S; Melcher, Jennifer R (2006) Effects of sound level on fMRI activation in human brainstem, thalamic and cortical centers. Hear Res 215:67-76
Sigalovsky, Irina S; Fischl, Bruce; Melcher, Jennifer R (2006) Mapping an intrinsic MR property of gray matter in auditory cortex of living humans: a possible marker for primary cortex and hemispheric differences. Neuroimage 32:1524-37
Hawley, Monica L; Melcher, Jennifer R; Fullerton, Barbara C (2005) Effects of sound bandwidth on fMRI activation in human auditory brainstem nuclei. Hear Res 204:101-10
Harms, Michael P; Guinan Jr, John J; Sigalovsky, Irina S et al. (2005) Short-term sound temporal envelope characteristics determine multisecond time patterns of activity in human auditory cortex as shown by fMRI. J Neurophysiol 93:210-22
Talavage, Thomas M; Edmister, Whitney B (2004) Nonlinearity of FMRI responses in human auditory cortex. Hum Brain Mapp 22:216-28
Penagos, Hector; Melcher, Jennifer R; Oxenham, Andrew J (2004) A neural representation of pitch salience in nonprimary human auditory cortex revealed with functional magnetic resonance imaging. J Neurosci 24:6810-5

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