Subject: Re: Uncertainty principle debate From: Eckard Blumschein <Eckard.Blumschein(at)E-TECHNIK.UNI-MAGDEBURG.DE> Date: Mon, 9 Feb 2004 11:13:11 +0100Greetings Alwan, Why not considering Figs 1 and 10 of your 1993 paper an indication for transition from cochlear resolution, extending down to 10 and 20 ms and strongly depending on both bandwidth and duration, towards resolution of brain for larger duration? In the latter case, I do not expect bandwidth and duration to matter much. Incidentally, in your earlier paper I found twice the word spectogram. Was this just a typo or did you mean something else than a spectrogram? Admittedly, my English is very shaky. Concerning the question by Ramdas Kumaresan for cochlear delay, I would like to add that polarity makes a clearly audible difference in particular below 200 Hz. This difference is to be seen in data by Nelson Kiang, Yidao Cai, Mario Ruggero and many others as well as in the natural spectrogram. Of course, there is considerable variability with respect to CF map among animals with or without an acoustic fovea. Also, at least 0.1 ms synaptic delay plus, in case of very low SPL, a few "warm-up" cycles of the OHC motors have to be taken into account. Nonetheless cochlear delay seems to roughly depend on the reciprocal of CF, as given by Steven Greenberg. This is not just a plausible strong additional argument in favor of seeing the traveling wave an epiphenomenon but also, as Armand Dancer stated, it simplifies modeling of cochlea. Therefore I would not entirely exclude the possibility that phonetics will immediately a little bit benefit from replacing the traditional spectrogram by the "natural" one, in particular if one deals not just with bilabial plosives but also with dental, alveolar, retroflex, palatal, glottal, and velar ones, with implosives, and with ejectives. However, my main concern is a sound basis for an understanding of the dominating mechanism of hearing as a cepstrum-like joint analysis involving both the fundamental cochlear frequency analysis and based on it a second analysis within brain. Your preference for a place/rate code is not very convincing to me because it cannot account for the wealth of audible nuances, robustness against noise, etc. A lot of evidence for the second analysis was given by Gerald Langner: http://www.swets.nl/JNMR/vol26_2.html #Langner26.2 http://eos.bio.tu-darmstadt.de/aglangner/langner.html What about the uncertainty, you and others are quite right: Hearing performs multiple recognition in parallel. I guess, the perception of different autocorrelation lags seemingly 'at a time' largely relates to the brain's prudent unability to resolve its internal frequencies much in excess of 40 Hz. Regards, Eckard