Michael Merzenich and stroke patients
Michael Merzenich and stroke patients
|31. 'Making an organism is a pretty horrendously complex thing'||270||01:40|
|32. Ed Lewis||250||00:37|
|33. The sciences of recognition and population thinking||394||01:44|
|34. An original thought at Zurich airport||1||537||02:52|
|35. The Neurosciences Research Program||429||03:53|
|36. Why I don't think the brain is a computer||838||03:51|
|37. The theory of neural Darwinism||972||05:14|
|38. The idea of re-entry||1||698||03:40|
|39. The idea of value||567||03:43|
|40. Response to criticism of Neural Darwinism||528||05:08|
I mentioned that one of ways in which you can get fervor and sometimes negative fervor, is to produce a... produce a theory in biology, especially a global one, because you're accused of hubris, of extraordinary overarching ambition, even though it isn't ambition – it's more like aspiration and seeking to understand. But there is something else about it and I respond by saying that, in addition to its range, this book Neural Darwinism that I wrote was considered to be hair-raisingly dense – in fact, one famous neurobiologist said to me, ‘I put in on my night table and I try to read one page, and it's like trying to read a whole book; haven't you got any mercy? Can't you open this thing up?’ And it's true that there was an extraordinary amount of consideration of dense subjects. But I, in fact, told this chap that, when I finished writing this book – even this book, never mind the one that I did way back in 1977 or 8... when I finished writing this I felt like a Roman centurion at the time of the Caesars, battling each other, and I came home, they said what was it like and I was full of blood and mud and all kinds of things that were not at all resolved and that involved enormous amounts of struggle. Because what my chief motivation was in writing this book was the idea that a theory in biology above all, even if it can't be predictive, should relate disparate findings. They should make understanding possible. And it seemed to me the things that I was considering were not held mutually. In fact, I considered that the field was in crisis. What do I mean by that?
Well, crisis in biology is not the same as crisis in physics. In physics for instance you had that famous one that took all of classical physics down called The Ultraviolet Catastrophe, that Planck first addressed, when you had a black body radiator and you increased its temperature according to the so-called Wien law, what happened as you approached the ultraviolet is the solution became infinite and it was a catastrophe and only by assuming the energy was put forth in quanta could you solve the problem of radiation from a black body and that began quantum mechanics. And you had to take down all of physics at that point.
Well, in biology you can always blame the other guy, and I say there's a crisis in cognitive science but, thank God, not in anatomy, or there's a crisis in neurophysiology but, thank God, not in cognitive science, etcetera. And here I was trying this very effortful thing and I admit that, to this very day, it has a flavor of... the sense of an ending is not fully there. And so you have to be a little more careful about what it is you're saying and you can't look back retrospectively with the same kind of satisfaction as you can, say, with the antibody problem. And that came out very clearly to me and it's still true... it's uppermost in my mind right now. But I did feel there was one thing about this theory that did depend on the others, not on me, and that was to get a group of people at the Neuroscience Institute particularly to do these models which are based on the theory and show that they work. So, for example, one of the hardest things to show, and one of the hardest things to understand, is this problem of re-entry.
Well, we actually made models of re-entry, and maybe the best way of conveying what entry... re-entry is doing in a selectional system and a brain theory like neural Darwinism is to use the analogy of a string quartet. Consider that you have a string quartet consisting of four very stubborn individual players. And each one decides he's going to play in the meter he wants and in the melodic system that he wants, diatonic or otherwise, and when you listen you hear just a discordant mess. Now supposing some genie comes along and hooks up every part of the body of every player with minute, almost invisible threads, so that when a violinist leans forward to do X and a cellist moves backward, that's conveyed to the other guys. Well, pretty soon you will notice that what happens is they tend to play more and more in synchrony – they tend then to approach each other at least in partial forms to create circles of what I'll call the re-entry. That's the closest I can come, because in fact it is sitting still is one thing, it's not a solution like in physics – for feedback, you have something called first order lag with dead time; you send a correction function back on one circuit and you fix it so your sine wave is now more accurate. Here it's this incredible complexity. But gradually, as a result of dynamic interactions and simultaneity and in the nervous system changing the synaptic strengths, you get coherency, you get simultaneity, and it's those things that act as part of the repertoire that you're going to put out that is selection on your behavior.
US biologist Gerald Edelman (1929-2014) successfully constructed a precise model of an antibody, a protein used by the body to neutralise harmful bacteria or viruses and it was this work that won him the Nobel Prize in Physiology or Medicine in 1972 jointly with Rodney R Porter. He then turned his attention to neuroscience, focusing on neural Darwinism, an influential theory of brain function.
Title: Response to criticism of "Neural Darwinism"
Listeners: Ralph J. Greenspan
Dr. Greenspan has worked on the genetic and neurobiological basis of behavior in fruit flies (Drosophila melanogaster) almost since the inception of the field, studying with one of its founders, Jeffery Hall, at Brandeis University in Massachusetts, where he received his Ph.D. in biology in 1979. He subsequently taught and conducted research at Princeton University and New York University where he ran the W.M. Keck Laboratory of Molecular Neurobiology, relocating to San Diego in 1997 to become a Senior Fellow in Experimental Neurobiology at The Neurosciences Institute. Dr. Greenspan’s research accomplishments include studies of physiological and behavioral consequences of mutations in a neurotransmitter system affecting one of the brain's principal chemical signals, studies making highly localized genetic alterations in the nervous system to alter behavior, molecular identification of genes causing naturally occurring variation in behavior, and the demonstration that the fly has sleep-like and attention-like behavior similar to that of mammals. Dr. Greenspan has been awarded fellowships from the Helen Hay Whitney Foundation, the Searle Scholars Program, the McKnight Foundation, the Sloan Foundation and the Klingenstein Foundation. In addition to authoring research papers in journals such as "Science", "Nature", "Cell", "Neuron", and "Current Biology", he is also author of an article on the subject of genes and behavior for "Scientific American" and several books, including "Genetic Neurobiology" with Jeffrey Hall and William Harris, "Flexibility and Constraint in Behavioral Systems" with C.P. Kyriacou, and "Fly Pushing: The Theory and Practice of Drosophila Genetics", which has become a standard work in all fruit fly laboratories.
Tags: Neural Darwinism, The Ultraviolet Catastrophe, Neuroscience Institute
Duration: 5 minutes, 8 seconds
Date story recorded: July 2005
Date story went live: 24 January 2008