Subject: Re: triggers for neural activity in the auditory periphery From: "Dennis P. Phillips" <Dennis.Phillips(at)DAL.CA> Date: Tue, 11 May 2004 09:51:14 -0300--============_-1127842622==_ma============ Content-Type: text/plain; charset="us-ascii" ; format="flowed" 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 -- ------------------------------------- Dennis P. Phillips, Ph.D., Professor, Hearing Research Laboratory Department of Psychology Dalhousie University Halifax, NS, Canada B3H 4J1 E-mail: Dennis.Phillips(at)Dal.Ca ------------------------------------- --============_-1127842622==_ma============ Content-Type: text/html; charset="us-ascii" <!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"><!-- blockquote, dl, ul, ol, li { padding-top: 0 ; padding-bottom: 0 } --></style><title>Re: triggers for neural activity in the auditory perip</title></head><body> <div>Hi Annemarie:</div> <div><br></div> <div>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.</div> <div><br></div> <div>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.</div> <div><br></div> <div>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.</div> <div><br></div> <div>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).</div> <div><br></div> <div>I hope that this helps. All good wishes,</div> <div><br></div> <div>Dennis</div> <div><br></div> <div><br></div> <div><br></div> <div><font color="#000000">Heil, P. (1997a) Auditory onset responses revisted. I. First-spike timing. J. Neurophysiol., 77: 2616-2641.<br> Heil, P. (1997b) Auditory onset responses revisted. II. Response strength. J. Neurophysiol., 77: 2642-2660.<br> 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.</font><br> </div> <div><font color="#000000">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.</font></div> <div>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.</div> <div><br></div> <div><font color="#000000">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.</font></div> <div><br></div> <div><br></div> <blockquote type="cite" cite><font face="Arial" size="-1">Dear List,</font><br> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1"> </font><br> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">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?</font><br> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1"> </font><br> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">With best regards!</font><br> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1"> </font><br> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">Annemarie</font></blockquote> </body> </html> --============_-1127842622==_ma============--