Re: 40 Hz RIP (DeLiang Wang )

Subject: Re: 40 Hz RIP
From:    DeLiang Wang  <dwang(at)CIS.OHIO-STATE.EDU>
Date:    Wed, 28 May 1997 09:51:30 -0400

Neil, > > The vision community is a better place to voice your complaints, > > Now hang on just a minute DeLiang. You have made some grand > claims concerning the application of the "oscillatory > framework" to both visual and auditory processing. Also, as you > will admit, apart from the references I have given above, the > experimental literature you have been using to support your > auditory models is *visual*. It is therefore perfectly > legitimate for us to question the nature of that visual > evidence. We have some very good vision people here in > Manchester with whom I am in regular contact. The reason I said that your doubts on experimental findings in the visual system should be expressed to the vision community is quite obvious: We, on the auditory list, are not experts (forgive me if some of you are) on visual experiments and thus can't judge the value of your doubts. Further, if your doubts have any value, you could make a contribution by raising them to those experimentists who work on these topics, such as Wolf Singer. As most of you would agree, those people who report coherent oscillations in the visual system are well-respected experimentalists and the vision community is full of smart critics. Relating to your specific doubts that visual experimentalists forget eye movements, here is a quote from a recent paper by A. Kreiter and W. Singer (1996) who report coherent oscillations in awake monkeys: "Similarly, the failure to find sharp stimulus-induced peaks ... excludes the possibility that eye movements may have caused the correlations" (J. Neurosci., vol. 16, p. 2391). Let me repeat, we am not in a good position to judge doubts on experiments. Those of you who have read our papers will notice that we quoted more than the list provided by Neil on auditory experiments (e.g. several papers from R. Llinas' group in NYU). Plus, the literature is evolving. > > The above idea was used in an early paper on oscillatory > > associative memory > > (Wang, Buhmann, and von der Malsburg, 1990, refs. below) to handle the > > overlap problem, essentially the same as the above problem. > > But the oscillator > > model used there proves to be too clumpsy. A recent model by > > Brown and Wang > > (1996) explicitly addressed the problem of "duplex > > perception" in audition > > using the same idea. But the Brown/Wang model is based on > > relaxation > > oscillator networks, which have an elegant theory and > > computational properties > > behind (see below). > > It is clear that the in the first scheme you envisaged the > frequency of the oscillators had only an arbitrary relationship > to the objects or features they were binding, i.e. there is > nothing double about the relationship between TABLE and BALL. In Fig. 3 of our paper (I forgot to give ref. last time, it is in Neural Computation, vol. 2, pp. 94-106), the overlapping parts between different patterns oscillate with either double frequency of bursts or triple frequency. One can easily link that simulation with 3 patterns to the current example of RED, BLUE, TABLE (I wish that we could foresee the current debate and thus label those patterns accordingly :-) ). > i.e. it is itself a signal. Any further oscillatory computation > is entirely redundent. I are not aware of any advocate of the oscillatory framework who says that you need oscillations for EVERYTHING. Auditory modeling existed long before the notion of temporal correlation was introduced. As I emphasized repeatedly in my first message of May 20, oscillatory correlation is a representation, and computation is a different dimension. Even as a representation, it is one alternative. Those of us who work on oscillatory correlation see computational advantages, but no surprise that other studies don't use this representation. And in this case, of course, it is redundant, just like the representation you use is redundent from our perspective. I am sure that most have had enough with this debate, and I hope that I have made my understanding of oscillatory correlation clear. If any of you in the auditory list still have questions, you are more than welcome to communicate with me privately as some did already. Cheers, DeLiang

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