Subject: Re: Rationale for Critical Bands From: Peter Meijer <feedback@xxxxxxxx> Date: Tue, 15 Jun 2010 08:58:54 +0200 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Thank you for these very interesting references, Martin. To the extent that critical bands find their origin in the ICC, one could conjecture that critical bands may be subject to (some) neural plasticity. Are there any studies with, say, young animals to see if the distribution of critical bands can be modified through suitable exposure and training with sounds, e.g., aimed at narrowing the critical bands? Natural settings for critical bands would likely already be "optimal" in some sense for natural sounds, but it would be interesting to know if adaptation is possible in (artificial) situations where an optimal setting would be different. Perhaps even a dynamic modulation of critical bands depending on momentary needs would be possible in cases where that serves the optimality condition. A quick web search turns up references like http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2474628/ http://jn.physiology.org/cgi/content/full/93/1/71 The second of these two references does seem to get close to addressing my question, but I'm not sure if it is the most representative example. I am personally most interested in possible effects of plasticity with complex sounds that are non-harmonic, with close to 20 tones - or more - per octave in a log distribution. Standard critical bands cause a within-band temporal "roughness" that might play a role in guiding effects of plasticity for a better spectral envelope discrimination with complex sounds, but I am not aware of much literature on this so would appreciate to learn more about it. Thanks and best regards, Peter Meijer Seeing with Sound - The vOICe http://www.seeingwithsound.com > Date: Mon, 14 Jun 2010 15:12:16 +0200 > From: Martin Braun<nombraun@xxxxxxxx> > Subject: Re: Rationale for Critical Bands > > Dear Dan, and list, > > You are quite right. The level independence of the critical bandwidths (C= > B)=20 > over wide sound level ranges excludes an origin in the cochlea. > > There are compelling data indicating that the origin is in the central=20 > nucleus of the inferior colliculus (ICC). > > http://www.ncbi.nlm.nih.gov/pubmed/3975613 > > http://www.ncbi.nlm.nih.gov/pubmed/7677631 > > http://www.ncbi.nlm.nih.gov/pubmed/9237756 > > http://www.ncbi.nlm.nih.gov/pubmed/10190753 > > http://www.ncbi.nlm.nih.gov/pubmed/10867285 > > Enjoy, > > Martin