Re: triggers for neural activity in the auditory periphery

["Dennis P. Phillips" <Dennis.Phillips@xxxxxx>]

Title: Re: triggers for neural activity in the auditory perip

Hi Annemarie:

There are at least two "levels" at which one can consider your question.  One level is that of discrete auditory events, e.g., the onset of some stimulus.

Peter Heil and Dexter Irvine have published a very nice program of work, in anesthetized cats and using tonal stimuli, which showed the importance of rate of change of pressure (at least for linear rise-time stimuli) in determining both response amplitude and response latency at the auditory nerve and in more central structures.  I've pasted the references to some of this work below.

Bob Burkard's group and mine have confirmed some of the foregoing findings in unanesthetized animals and using noise stimuli.  References to some of that work are also pasted below.  The 2002 review article provides a broader context for this line of enquiry.

The second level is that of the individual cycles of an ongoing tonal (or other) stimulus, as in the case of phase-locking.  In that instance, motion of the cochlear partition towards scala vestibuli contributes significantly to the excitatory phase of the transduction process.  Some of this work is reviewed by Ruggero (1992, reference below).

I hope that this helps.  All good wishes,

Dennis

Heil, P.  (1997a)  Auditory onset responses revisted.  I.  First-spike timing.  J. Neurophysiol., 77: 2616-2641.
Heil, P.  (1997b)  Auditory onset responses revisted.  II.  Response strength.  J. Neurophysiol., 77: 2642-2660.
Heil, P. and Irvine, D.R.F.  (1997)  First-spike timing of auditory-nerve fibers and comparison with auditory cortex.  J. Neurophysiol., 78: 2438-2454.

Phillips, D.P., Hall, S.E., Guo, Y-Q and Burkard, R.  (2001)  Sensitivity of unanesthetized chinchilla auditory system to noise burst onset, and the effects of carboplatin.  Hearing Res., 155: 133-142.

Phillips, D.P., Hall, S.E. and Boehnke, S.E.  (2002)  Central auditory onset responses, and temporal asymmetries in auditory perception.  Hearing Res., 167: 192-205.

Ruggero, M.A.  (1992)  Physiology and coding of sound in the auditory nerve. In: A.N. Popper and R.R. Fay (Eds.), The Mammalian Auditory Pathway: Neurophysiology.  New York: Springer-Verlag, pp34-93.

> Dear
> List,
>  
> are there
> any physiological studies on the question, what are the exact triggers
> for the activation of auditory brainstem nuclei? I am especially
> interested in the question whether the CN responds to abrupt peaks in
> the activity of the auditory nerve, or rather exhibits temporal
> integration characteristics before becoming active itself. Is there
> any knowledge about the order of such integration times and are they
> frequency-specific?
>  
> With best
> regards!
>  
> Annemarie