Subject: Re: comodulation release of masking (CMR) From: Neil Todd <TODD(at)FS4.PSY.MAN.AC.UK> Date: Fri, 2 Oct 1998 17:46:50 GMTDear Steven Date: Fri, 2 Oct 1998 15:38:24 +0200 Reply-to: par(at)IPO.TUE.NL From: par(at)IPO.TUE.NL Subject: Re: comodulation release of masking (CMR) >> >I think there is no consensus about the processing of CMR >stimuli although we recently argued that the envelope cross correlation >(not to mistake with the envelope cross covariance or correlation >coefficient) may be helpful in accounting for CMR data >(van de Par and Kohlrausch, 1998a/b: JASA 103 pp 3605-3620; 1573-1579). >In the paper on page 3605 we even describe a model that accounts >for CMR data. > >Steven > > I think we are agreed that some form of cross-correlation mechanism is probably a good horse to bet on, I wonder though if you could clarify your distinction between different forms of cross-correlation. The cross-correlation mechanism I proposed in Todd (1996, Network: Computation in Neural Systems. 7, 349-356) was a product-moment on the cosine phase of the envelope modulation power spectrum. This had the advantage that one didn't need to have delay lines or some other storage mechanism since if one uses acausal impulse response function (or non-linear phase response transfer function) for the modulation filter, this is effectively a kind of memory. Further, the cosine phase spectrum locks into that of the envelope thus preserving sensitivity to phase effects in streaming (e.g. in an alternating A B A B sequence). I did play around with some other metrics, e.g. Euclidean distance, but did not conclude that there was any advantage over the product-moment, although I did consider how such a cross-correlation mechanism might be instantiated neurally. Best wishes Neil University of Manchester Manchester M13 9PL UK Tel. +44 (0)161 275 2557 Email to AUDITORY should now be sent to AUDITORY(at)lists.mcgill.ca LISTSERV commands should be sent to listserv(at)lists.mcgill.ca Information is available on the WEB at http://www.mcgill.ca/cc/listserv