Subject: Re: AUDITORY Digest - 17 Mar 2004 to 18 Mar 2004 (#2004-54) From: "Anamaria S. Kazanis" <akazanis(at)UMICH.EDU> Date: Fri, 19 Mar 2004 08:16:24 -0500I would like to unsubscribe from the Auditory Digest. Thank you, Anamaria Kazanis akazanis(at)umich.edu --On Friday, March 19, 2004 12:00 AM -0500 Automatic digest processor <LISTSERV(at)LISTS.MCGILL.CA> wrote: > There are 10 messages totalling 716 lines in this issue. > > Topics of the day: > > 1. Is there considerable phase locking up to 6 kHz? (4) > 2. 2 post-doctoral positions in music structure research (London, UK) > 3. Critical bands - fixed or "floating"? > 4. Discussion about "place pitch" concept (3) > 5. seeking an image of the auditory system > > ---------------------------------------------------------------------- > > Date: Thu, 18 Mar 2004 09:53:10 +0100 > From: Eckard Blumschein <Eckard.Blumschein(at)E-TECHNIK.UNI-MAGDEBURG.DE> > Subject: Re: Is there considerable phase locking up to 6 kHz? > > Dear all, > > I appreciate clear objections against the idea of periodicity detection > from temporal envelope by Roy Patterson: "The work on IRN stimuli suggests > that periodicities are not a necessary and sufficient condition for > processing complex pitch, since there are no periodicities in the IRN > waveform (see Yost et al, 1996), yet they have a clear pitch (see Yost, > 1996a). Our current work suggests that the information for processing the > pitch of IRN stimuli is not in the envelope." > > However, we all should be wary of thoughtlessly using notions like > spectrum and temporal fine structure. > Already the fundamentally inappropriate traditional spectrogram > illustrates that the iteration of a segment of noise without any spectral > profile introduces an audible spectral signature. Of course, the > FCT-based natural spectrogram shows a more realistic picture of firing > pattern in the auditory nerve. I remind those who do not trust in FCT, > because they wrongly put it in the drawer of an exotic mathematical idea > while it actually replaces FT, of the need to define what we are talking > about if we are using terms like spectral component. > > Martin Braun is certainly correct in that, there are at least two main > streams of auditory information within each CN. However, he apparently > ignores tonotopy as long as he doesn't follow my suggestion that place > code is the best base for subsequent temporal processing. For more than a > century, Fourier analysis and place code were considered the basis of > hearing and of related audio technology because alternative temporal > models failed. > > Why not seriously dealing with an unseen mathematically correct and > physiologically plausible model that unites function of cochlea and brain > in a somewhat strange hidden manner which is already known as cepstral > analysis? It also may elucidate why different codes contribute to a > unitary pitch. > > I do not appreciate glossing over FCT as a red herring since such > emotional arguments are difficult to falsify. Nonetheless, I would hope > that expert listeners confirm or deny the putative 400/800 Hz confusion. > So far, I am only aware of a plausible 50/100 Hz confusion in case of > iterated noise segments with alternating polarity inversion (Warren & > Wrightson 1981). > > Eckard Blumschein > > ------------------------------ > > Date: Thu, 18 Mar 2004 09:46:52 +0000 > From: Michael Casey <casey(at)SOI.CITY.AC.UK> > Subject: 2 post-doctoral positions in music structure research (London, > UK) > > Dear Auditory list members, > > the following post-doctoral positions may be suitable for recent PhD's > with a background in auditory research. (Closing March 22nd). > > Best regards, > > Dr. Michael Casey, Lecturer > Centre for Computational Creativity > City University, London > http://ccc.soi.city.ac.uk > +44 (0)20 7040 8380 > > Job Title: Post-Doctoral Research Assistant for SeMMA project > Tenure: Fixed term for three years > Responsible to: Prof. Mark Sandler (Queen Mary College University of > London) and Dr Michael Casey (City University London) > > Project Overview: > The 3 year Engineering and Physical Sciences Research Council (EPSRC) > project Hierarchical Segmentation and Semantic Markup of Musical Signals > is a collaboration between the Centre for Digital Music at Queen Mary > University of London and the Centre for Computational Creativity at City > University. It is concerned with the extraction and exploitation of > musically relevant semantic features direct from musical content. Each > partner will employ one post-doctoral researcher. It is expected that both > researchers will spend some time in each other's laboratory, which are > only about 2 miles apart in Central London. > > Main Duties: > The aim of this research programme is to develop new signal processing > algorithms that perform meaningful segmentations of musical signals. The > specific objectives are to: > > develop new machine learning techniques to automatically produce a > hierarchical segmentation directly from an audio recording > evaluate the methods and algorithms using a test corpus consisting of a > range of different musical styles and recording qualities > develop a framework to construct two applications (information retrieval > & intelligent editing) and evaluate the performance and opportunities > > The post-docs will engage in research to fulfil the requirements of the > grant. They must have expertise in some of the following research areas: > > DSP for Music and Audio. > Statistical (Bayesian) Modelling and Statistical Mechanics > Low level audio feature extraction (e.g. MFCC) > Databases and Music Information Retreival > MPEG7, XML, C++, Java, Matlab > > They will be required to co-operate with and to communicate with members > of the research team at the other partner, and be required to attend > regular project meetings. > > The post-docs will be required to write and to edit contributions to > project documents, including learned papers for journals and conferences. > Additionally the post-doc will be offered the opportunity to lecture on > Masters level courses as part of career development. > > Deadline for applicatoin: 5PM GMT 22nd March '04 > For details of how to apply see > http://www.city.ac.uk/hr/jobs/04046/dp.htm > > ------------------------------ > > Date: Thu, 18 Mar 2004 14:26:27 +0100 > From: Martin Braun <nombraun(at)TELIA.COM> > Subject: Re: Is there considerable phase locking up to 6 kHz? > > On Thursday, March 18, 2004 3:40 AM, Richard F. Lyon wrote: > > > Martin, thanks for your comments. I will be more than happy to adopt > > your suggestion and give up the old idea of "place pitch" as > > unsupportable by any evidence. > > > > However, I'm not sure I like your division of timing pathways. > > > > The first one (a), with "phase locking of resolved harmonics" seems > > to be rather narrowly construed. Sound does not in general > > consistent of discrete sinusoids, since it is not in general > > periodic, so the mechanisms must be much more general. Even for > > periodic sounds, partials are in general only partly "resolved". The > > phase locking in the auditory nerve will follow the time structure of > > arbitrary waveforms at the different points along the cochlea. > > Conceptualizing in terms of sinusoids does more harm then good, in my > > opinion. > > Yes, Dick, what the cochlea and then various nuclei in the auditory > pathways do is much more than delivering clean phase coupling to clean > sinusoid components. We see various techniques of band filtering and the > final results are probabilistic. But, as FFR studies showed (frequency > following responses recorded on the human scalp originating in the upper > brain stem), the neural population responses reflect a remarkably clean > periodicity coding upon complex periodic stimuli. > > > > The second pathway (b) seems funny, too. Why would information be > > encoded "for the purpose of sound localization" and then used for a > > different purpose? > > Because many, if not most, neurons in the cochlear nuclei and in the > nuclei of inferior colliculus are multiplexing units. Monaural delay > coding in the cochlear nuclei and binaural delay coding in nuclei of the > superior olivary complex does not occur in units that are exclusively > engaged in sound localization. Therefore, not only the results of delay > analysis are delivered upstream, but also the raw delay periods. The > period detectors in the midbrain then (periodicity tuned neurons) respond > to these delays, simply because they present period information. > > The environments that our hearing has adapted to did not present stimuli > where proper and secondary pitch pathways can come up with conflicting > results. So there was no evolutionary advantage of fully separating the > mechanisms for sound localization and pitch extraction. > > Martin > > -------------------------------- > Martin Braun > Neuroscience of Music > S-671 95 Klässbol > Sweden > web site: http://w1.570.telia.com/~u57011259/index.htm > > ------------------------------ > > Date: Thu, 18 Mar 2004 13:52:55 -0000 > From: "Richard H." <auditory(at)AUGMENTICS.COM> > Subject: Critical bands - fixed or "floating"? > > Hi, > > Newbie question: are the critical bands physically real measurable bands - > or are they simply a "ratiometric artefact"? > > regards, > > Richard > > > --- > Outgoing mail is certified Virus Free. > Checked by AVG anti-virus system (http://www.grisoft.com). > Version: 6.0.631 / Virus Database: 404 - Release Date: 17/03/04 > > ------------------------------ > > Date: Thu, 18 Mar 2004 17:24:55 +0100 > From: Eckard Blumschein <Eckard.Blumschein(at)E-TECHNIK.UNI-MAGDEBURG.DE> > Subject: Re: Is there considerable phase locking up to 6 kHz? > > Dear Martin, > > At 14:26 18.03.2004 +0100, you wrote: > ... many, if not most, neurons in the cochlear nuclei and in the nuclei > > of inferior colliculus are multiplexing units. > > Do you know how a multiplexer works, and can you specify the pertaining > role you are ascribing to spherical bushy cells and T-multipolars of CN, > at least? > > Regards, > Eckard > > ------------------------------ > > Date: Thu, 18 Mar 2004 08:33:15 -0800 > From: "Richard F. Lyon" <DickLyon(at)ACM.ORG> > Subject: Re: Is there considerable phase locking up to 6 kHz? > > --============_-1132494356==_ma============ > Content-Type: text/plain; charset="iso-8859-1" ; format="flowed" > Content-Transfer-Encoding: quoted-printable > > At 9:53 AM +0100 03/18/2004, Eckard Blumschein wrote: > > However, we all should be wary of thoughtlessly using notions like > > spectrum and temporal fine structure. > > > I'm glad that we have that point of agreement. > > > > Already the fundamentally inappropriate traditional spectrogram > > illustrates that the iteration of a segment of noise without any > > spectral profile introduces an audible spectral signature. Of course, > > the FCT-based natural spectrogram shows a more realistic picture of > > firing pattern in the auditory nerve. I remind those who do not trust > > in FCT, because they wrongly put it in the drawer of an exotic > > mathematical idea while it actually replaces FT, of the need to define > > what we are talking about if we are using terms like spectral component. > > > I'm trying to decide whether that comment is=20 > directed at me. Certainly I've always been very=20 > careful about concepts such as spectral=20 > components, as I believe the such=20 > frequency-domain concepts often force thinking=20 > into wrong directions. I also don't regard=20 > =46ourier Cosine Transforms as any more exotic than=20 > other mathematical transforms. But I do mistrust=20 > them as auditory models. > > > > Martin Braun is certainly correct in that, there are at least two main > > streams of auditory information within each CN. However, he apparently > > ignores tonotopy as long as he doesn't follow my suggestion that place > > code is the best base for subsequent temporal processing. For more than > > a century, Fourier analysis and place code were considered the basis of > > hearing and of related audio technology because alternative temporal > > models failed. > > > Here we have a different view of the impact of=20 > the Fourier analysis approach and place code on=20 > the historical development of auditory theory.=20 > I'm more aligned with a quote that I heard=20 > attributed to Georg von B=E9k=E9sy: "Dehydrated cats=20 > and the application of Fourier analysis to=20 > problems in hearing become more and more a=20 > handicap for progress in hearing research." > > As far as I know, temporal models have succeeded=20 > more than failed (that is, temporal models of=20 > processing in and beyond the cochlea, not to be=20 > confused with temporal processing of raw sound=20 > waveforms). Spectral models, while widely used,=20 > often run into limitations that make them "fail". > > > > Why not seriously dealing with an unseen mathematically correct and > > physiologically plausible model that unites function of cochlea and > > brain in a somewhat strange hidden manner which is already known as > > cepstral analysis? It also may elucidate why different codes contribute > > to a unitary pitch. > > > Cepstral analysis is fine as far as it goes. But=20 > it is rather limiting, as a mathematical=20 > framework that stops short of describing what's=20 > going on in detail, essentially ignoring temporal=20 > fine structure on the auditory nerve. > > > > I do not appreciate glossing over FCT as a red herring since such > > emotional arguments are difficult to falsify. Nonetheless, I would hope > > that expert listeners confirm or deny the putative 400/800 Hz > > confusion. So far, I am only aware of a plausible 50/100 Hz confusion > > in case of iterated noise segments with alternating polarity inversion > > (Warren & Wrightson 1981). > > > OK, this part I'm certain is directed at me,=20 > since I mentioned red herrings. My comment was=20 > not directed at the FCT itself, which is a=20 > perfectly fine transform, but rather to the idea=20 > that if you use it then you can ignore questions=20 > of temporal fine structure. Specifically, what I=20 > said quoted your assertion, this way ...the idea=20 > that "FCT is the only realistic cochlear=20 > transform" is just a mathematician trying to=20 > force a biological system to be something he can=20 > analyze.' I apologize for putting it in such=20 > personal terms. > > Dick > > > > Eckard Blumschein > > --============_-1132494356==_ma============ > Content-Type: text/html; charset="iso-8859-1" > Content-Transfer-Encoding: quoted-printable > > <!doctype html public "-//W3C//DTD W3 HTML//EN"> > <html><head><style type=3D"text/css"><!-- > blockquote, dl, ul, ol, li { padding-top: 0 ; padding-bottom: 0 } > --></style><title>Re: Is there considerable phase locking up to 6 > kHz?</title></head><body> > <div>At 9:53 AM +0100 03/18/2004, Eckard Blumschein wrote:</div> > <blockquote type=3D"cite" cite>However, we all should be wary of > thoughtlessly using notions like spectrum</blockquote> > <blockquote type=3D"cite" cite>and temporal fine structure.</blockquote> > <div><br></div> > <div><br></div> > <div>I'm glad that we have that point of agreement.</div> > <div><br> > <br> > </div> > <blockquote type=3D"cite" cite>Already the fundamentally inappropriate > traditional spectrogram illustrates<br> > that the iteration of a segment of noise without any spectral > profile<br> > introduces an audible spectral signature. Of course, the FCT-based > natural<br> > spectrogram shows a more realistic picture of firing pattern in > the<br> > auditory nerve. I remind those who do not trust in FCT, because > they<br> > wrongly put it in the drawer of an exotic mathematical idea while > it<br> > actually replaces FT, of the need to define what we are talking about > if we</blockquote> > <blockquote type=3D"cite" cite>are using terms like spectral > component.</blockquote> > <div><br> > <br> > </div> > <div>I'm trying to decide whether that comment is directed at me. > Certainly I've always been very careful about concepts such as > spectral components, as I believe the such frequency-domain concepts > often force thinking into wrong directions. I also don't regard > =46ourier Cosine Transforms as any more exotic than other mathematical > transforms. But I do mistrust them as auditory models.</div> > <div><br></div> > <div><br></div> > <blockquote type=3D"cite" cite>Martin Braun is certainly correct in > that, there are at least two main<br> > streams of auditory information within each CN. However, he > apparently<br> > ignores tonotopy as long as he doesn't follow my suggestion that place > code<br> > is the best base for subsequent temporal processing. For more than > a<br> > century, Fourier analysis and place code were considered the basis > of<br> > hearing and of related audio technology because alternative temporal > models<br> > failed.</blockquote> > <div><br> > <br> > </div> > <div>Here we have a different view of the impact of the Fourier > analysis approach and place code on the historical development of > auditory theory. I'm more aligned with a quote that I heard > attributed to<font face=3D"Arial" size=3D"-3" color=3D"#000000"> Georg von > B=E9k=E9sy</font>: "Dehydrated cats and the application of > =46ourier analysis to problems in hearing become more and more a > handicap for progress in hearing research."</div> > <div><br></div> > <div>As far as I know, temporal models have succeeded more than failed > (that is, temporal models of processing in and beyond the cochlea, not > to be confused with temporal processing of raw sound waveforms). > Spectral models, while widely used, often run into limitations that > make them "fail".</div> > <div><br></div> > <div><br></div> > <blockquote type=3D"cite" cite>Why not seriously dealing with an unseen > mathematically correct and<br> > physiologically plausible model that unites function of cochlea and > brain<br> > in a somewhat strange hidden manner which is already known as > cepstral<br> > analysis? It also may elucidate why different codes contribute to a > unitary</blockquote> > <blockquote type=3D"cite" cite>pitch.</blockquote> > <div><br></div> > <div><br></div> > <div>Cepstral analysis is fine as far as it goes. But it is > rather limiting, as a mathematical framework that stops short of > describing what's going on in detail, essentially ignoring temporal > fine structure on the auditory nerve.</div> > <div><br> > <br> > </div> > <blockquote type=3D"cite" cite>I do not appreciate glossing over FCT as > a red herring since such emotional<br> > arguments are difficult to falsify. Nonetheless, I would hope that > expert<br> > listeners confirm or deny the putative 400/800 Hz confusion. So far, I > am<br> > only aware of a plausible 50/100 Hz confusion in case of iterated > noise</blockquote> > <blockquote type=3D"cite" cite>segments with alternating polarity > inversion (Warren & Wrightson 1981).</blockquote> > <div><br></div> > <div><br></div> > <div>OK, this part I'm certain is directed at me, since I mentioned > red herrings. My comment was not directed at the FCT itself, > which is a perfectly fine transform, but rather to the idea that if > you use it then you can ignore questions of temporal fine structure. > Specifically, what I said quoted your assertion, this way ...the idea > that "FCT is the only realistic cochlear transform" is just > a mathematician trying to force a biological system to be something he > can analyze.' I apologize for putting it in such personal > terms.</div> > <div><br></div> > <div>Dick</div> > <div><br> > <br> > </div> > <blockquote type=3D"cite" cite>Eckard Blumschein</blockquote> > <div><br></div> > </body> > </html> > --============_-1132494356==_ma============-- > > ------------------------------ > > Date: Thu, 18 Mar 2004 18:49:39 +0100 > From: "Dr. Uwe Baumann" <uwe.baumann(at)HNO.MED.UNI-MUENCHEN.DE> > Subject: Discussion about "place pitch" concept > > Dear Martin, Christian, Dick, Roy, and others - > > The ongoing discussion about temporal pitch emerged the statement=20 > > "There is no physiology of a "place pitch", and this concept should be = > given up." by Martin Braun, which was supported by several others. > > I would like to point the discussion to electrical excitation of the = > spiral ganglion cells by means of a cochlear implant electrode array. > With direkt pulsatile stimulation of the auditory nerve, Zengs' (2002) = > as well as our own results (Baumann & Nobbe, submitted) do clearly show, = > that: > > a) the upper limit for temporal pitch with pulsatile stimulation is 300 = > pulses per second > > b) pure temporal pitch discrimination (without place cues) is = > astonishingly worse: depending on base rate an average rate change of = > 23% to 33% pulse rate is required to elicit a just noticeable difference = > in terms of pitch perception. > > c) The absence of a difference in terms of repetition rate = > discrimination between apical and basal electrode locations indicates = > that a reduction of the base rate/place mismatch does not improve = > discrimination performance. > > d) Concerning autocorelation based models of pitch perception: > "With electrical stimulation, identical temporal information can be = > provided to different channels by independently stimulating basal and = > apical electrodes. The summed autocorrelation function should be = > identical between basal and apical stimulation, predicting an = > independence of rate pitch on the place of stimulation. This prediction = > is clearly inconsistent with the observed joint dependence > of pitch perception on rate and place [by pulsatile electrical = > stimulation]." (Zeng, 2002) > > There have been discussions about the reasons of the poor contribution = > of temporal information to pitch perception in electrical hearing. Poor = > neural survival is one major argument. But even in case of a reduced = > number of fibers, the rate code will be transmitted more accurately in = > electrical hearing than by normal acoustical stimulation (Hartmann, = > 1984). > > These and several other arguments will be discused in our alredy = > mentioned (presumably upcoming) paper. > > The outlined observations are not able to counter the notion "There is = > no physiology of place pitch", but they clearly indicate that there is a = > place pitch in psychophysical electrical stimulation of the cochlea by = > means of intracochlear electrode arrays. > > Uwe > > Dr.-Ing. Uwe Baumann > Electrical Engineer/Medical Physicist/Audiologist > University of Munich > Dept. Otolaryngology/Audiology > Marchioninistr. 15 > D-81377 M=FCnchen > Tel: ++49-89-7095-3878 > Fax: ++49-89-7095-6869 > email: uwe.baumann(at)med.uni-muenchen.de > www: http://ghn86x.hno.med.uni-muenchen.de/bau > > References: > > Baumann U, Nobbe A (2004) Pulse rate discrimination with deeply inserted = > electrodes. Hearing Research submitted > > Hartmann R, Topp G, Klinke R (1984) Discharge patterns of cat primary = > auditory fibers with electrical stimulation of the cochlea. Hear. = > Res.13:47-62 > > Zeng, F.-G. (2002) Temporal pitch in electric hearing. Hear.Res. 174, = > 101-106. > > ------------------------------ > > Date: Thu, 18 Mar 2004 23:07:23 +0100 > From: Martin Braun <nombraun(at)TELIA.COM> > Subject: Re: Discussion about "place pitch" concept > > On Thursday, March 18, 2004 6:49 PM, Uwe Baumann wrote: > > > There have been discussions about the reasons of the poor contribution > > of temporal information to pitch perception in electrical hearing. Poor > neural > > survival is one major argument. But even in case of a reduced number of > > fibers, the rate code will be transmitted more accurately in electrical > > hearing than by normal acoustical stimulation (Hartmann, 1984). > > Because this is an accuracy that is enforced rather "brutally". The price > of the "brutality" is the low limit of neural phase coupling. More > important than reduced numbers of afferent fibers in the cochlea probably > is the absence of inner hair cells and their afferent synapses. Both are > extremely sophisticated machines, which we only have started to explore. > The secrets of HF period coding are hidden here. > > > > The outlined observations are not able to counter the notion "There is > > no physiology of place pitch", but they clearly indicate that there is a > place > > pitch in psychophysical electrical stimulation of the cochlea by means > > of intracochlear electrode arrays. > > Thanks, Uwe. This is an important point. For peripheral encoding of period > information the place of encoding is important, also in normal hearing. > But this is not what theories of "place pitch" were dealing with. Rather, > they suggested a coding of pitch by central cochleotopic patterns of > harmonics, for which physiological evidence could never be found. > > By the way, there is a very recent and highly interesting paper which > demonstrates the importance of peripheral encoding place: Oxenham et al. > "Correct tonotopic representation is necessary for complex pitch > perception", which appeared in Proc. Natl. Acad. Sci. USA, published > online before print January 12, 2004 (10.1073/pnas.0306958101). > > This paper should be recommended to all who have to do with cochlear > implants. It is also of importance for physiological concepts of pitch. > For this reason I published a short comment on it: > > http://w1.570.telia.com/~u57011259/Oxenham.htm > > Martin > > -------------------------------- > Martin Braun > Neuroscience of Music > S-671 95 Klässbol > Sweden > web site: http://w1.570.telia.com/~u57011259/index.htm > > ------------------------------ > > Date: Thu, 18 Mar 2004 17:47:40 -0500 > From: Mark Ballora <ballora(at)PSU.EDU> > Subject: seeking an image of the auditory system > > Hello -- > > I am looking for an image of the human auditory system for use in a > brief article that I am writing on psychoacoustics. > > Can anyone on the list point me towards images that might be > available for licensing for use in a commercial publication > (Electronic Musician magazine). > > Thank you -- > > Mark Ballora > > > -- > ========================================================================= > ====== Mark Ballora > > http://www.music.psu.edu/Faculty%20Pages/Ballora/index.html > > Assistant Professor - Music Technology > School of Music/Dept. of Integrative Arts > The Pennsylvania State University tel. (814) 863-3386 > 14 Music Building II fax (814) 865-6785 > University Park, PA 16802-1901 USA > > The mysterious is the source of all true art and science. > He to whom this emotion is a stranger, > who can no longer pause to wonder and stand rapt in awe, > is as good as dead: his eyes are closed. > Albert Einstein > ========================================================================= > ====== > > ------------------------------ > > Date: Fri, 19 Mar 2004 10:51:30 +1100 > From: Colette McKAY <colette(at)UNIMELB.EDU.AU> > Subject: Re: Discussion about "place pitch" concept > > Uwe Baumann wrote: > * d) Concerning autocorelation based models of pitch perception: > * "With electrical stimulation, identical temporal information can > be = provided to different channels by independently stimulating basal > and = apical electrodes. The summed autocorrelation function should be = > identical between basal and apical stimulation, predicting an = > independence of rate pitch on the place of stimulation. This prediction = > is clearly inconsistent with the observed joint dependence > * of pitch perception on rate and place [by pulsatile electrical = > stimulation]." (Zeng, 2002) > *=09 > > However, there are many studies which have consistently demonstrated the = > independence of percepts related to rate of stimulation and place of = > stimulation. The earliest of these was Tong et al. (Tong, Y. C., P. J. = > Blamey, et al. (1983). "Psychophysical studies evaluating the = > feasibility of a speech processing strategy for a multiple-channel = > cochlear implant." Journal of the Acoustical Society of America 74(1): = > 73-80.) who used a multidimensional scaling task and showed a = > 2-dimensional stimulus space relating to rate and electrode position. > A more recent study was by McKay, C., H. McDermott, & Carlyon. (2000). = > "Place and temporal cues in pitch perception: are they truly = > independent?" Acoustic Research Letters Online 1(1): 25-30. We showed = > that subjects could use independent information about rate and place = > changes in a difference-limen task. Combined changes which were = > inconsistent (e.g. increasing rate and apicalward place shift) were = > equally discriminable to changes which were consistent and this was = > inconsistent with the idea that such information is combined into a = > single 'pitch' percept or.=20 > The latter study is inconsistent with studies such as Zeng (2002) in = > which the both place and rate seem to influence the 'pitch' estimate of = > the subject. My personal view on the reason for this inconsistency is = > that, when subjects are asked to rate the 'pitch' of sounds which differ = > both in pitch and timbre (as in the Zeng experiment) they are forced to = > make decisions based on two different percepts at once, and thus are = > forced to respond based on some weighted average of the two percepts. = > Also, an implantee (or even a normal hearing person) is likely to rank = > timbre as a pitch difference if played two sounds differing only in = > timbre. Experiments like this one tend to suggest that you can adjust = > the rate on one electrode to make an equal pitch to stimulation on = > another electrode at a different rate. However, if these two stimuli = > were directly compared by a subject they would immediately tell you they = > are very different sounds, with different pitches, and they would choose = > one of the place or rate percepts to tell you which one had the higher = > pitch. > > Colette McKay > > > > *********************************************************************** > A/Prof Colette McKay > NHMRC Principal Research Fellow > Department of Otolaryngology, The University of Melbourne > 384-388 Albert St. East Melbourne, Australia > Phone +613 9667 7506 Fax +613 9667 7518 > email: colette(at)unimelb.edu.au > ********************************************************************** > > ------------------------------ > > End of AUDITORY Digest - 17 Mar 2004 to 18 Mar 2004 (#2004-54) > ************************************************************** ******************************************************* Anamaria S. Kazanis, MA Research Associate II Health Sciences Grants and Research Office School of Nursing, rm 4245 University of Michigan akazanis(at)umich.edu 734.647.0467 **********************************************************