Calcium imaging of auditory nerve fiber terminals in the cochlear nucleus

J Neurosci Methods. 2011 Jan 30;195(1):24-9. doi: 10.1016/j.jneumeth.2010.11.008. Epub 2010 Nov 23.


One important model for understanding neuronal computation is how auditory information is transformed at the synapses made by auditory nerve (AN) fibers on the bushy cells (BCs) in the anteroventral cochlear nucleus (AVCN). This transformation is influenced by synaptic plasticity, the mechanisms of which have been studied primarily using postsynaptic electrophysiology. However, it is also important to make direct measurements of the presynaptic terminal to consider presynaptic mechanisms. Here we introduce a technique for doing that using calcium imaging of presynaptic AN terminals, by injecting dextran-conjugated fluorophores into the cochlea. To measure the calcium transients, we used calcium-sensitive fluorophores, and measured the changes in fluorescence upon stimulation. As an example of the application of this technique, we showed that activation of GABA(B) receptors reduces presynaptic calcium influx. This technique could be further extended to study the effects of activity- and other neuromodulator-dependent plasticities on AN terminals.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Cochlear Nerve / metabolism*
  • Cochlear Nucleus / metabolism*
  • Fluorescent Antibody Technique / methods*
  • Fluorescent Dyes
  • Immunohistochemistry
  • Mice
  • Microscopy, Fluorescence / methods
  • Organ Culture Techniques
  • Patch-Clamp Techniques
  • Presynaptic Terminals / metabolism*


  • Fluorescent Dyes
  • Calcium