1.2 Wiring and activity of auditory nerve fibers

Auditory nerve fibers convey sound-information from sensory cells to brainstem through neural spike trains. Dysfunction in the sound encoding process leads to deafness and tinnitus. Here, we combine morphological, electrophysiological investigations with computational modeling to examine the mechanism of sound encoding in the auditory nerve fibers.

A. Innervation of inner hair cells (IHCs) using confocal imaging. 3D isosurface reconstruction from confocal microscopy of immunostained gerbil IHC afferent synapses (ribbon and IHC nuclei, green; post-synaptic receptors, red; IHC cytoplasm, blue). Auditory nerve fibers makes contacts with the basal end of IHCs.

 

 

B. Single-unit recordings in the auditory nerve. Dot raster plots shows spike times (dots) for multiple repetitions of a tone-burst. For each repetition, the time of the first spike is highlighted by the large red dots.



1 2 illustration 02

 

C. Computational modeling of the sound-evoked firing of 807 fibers distributed along the tonotopic axis.
At low-level of stimulation, basilar membrane response is sharply frequency-tuned and activates ANFs of a narrow band corresponding to sound probe frequency. In contrast, responses to intense stimuli are poorly tuned and recruit additional ANFs from broadband region with predominance toward the basal region of the cochlea.


 

Major publications

Bourien J et al., J Neurophysiol, 112:1025-39, 2014
Sendin G et al., PNAS, 111(5):1999-2004, 2014
Ruel J et al., J Neurosci, 28:7313-23, 2008
Bourien J et al., Clin Neurophysiol, 116:443-55, 2005
Bourien J et al., IEEE Trans Biomed Eng, 51:304-15, 2004
Wendling F et al., Brain, 126:1449-59, 2003

Collaborations

  • Santos-Sacchi, Yale University,
  • Boris Gourévitch, ENS, Paris

Fundings

Cochlear   Neurelec   Entendre

Contact

Jérôme Bourien