Interview with Terry Sejnowski, Denver, 1993, ER: Maybe we could start with general biographical material, your date of birth, where you are from, how you grew up, your early education, your parents ... TS: You want to go back that far? ER: Absolutely, TS: Well, I was born in Cleveland in 1947 and went to college in Cleveland, Case Western Reserve, I graduated from there in '68, ER: Maybe we could back up a little bit. One of the things we're interested in is trying to find out how people became interested in the brain ,,. ER: OK. ER: What influence their parents had on this, how their growing up affected their interests ,,, ER: There were all these intangible influences, I grew up in a family where science was in the air. My father was a design engineer, so he had lots of motors and things that he would put together in the basement. So electricity and mechanical things were something that I was comfortable with. But actually, if you want an interesting historical document, you should take a look at iry high school literary magazine where I had a couple of essays. One of them was a short story about a government project which was meant to simulate a brain. It was a short story in the form of experiences Page 2 Terry Sejnowski 18 December 1996 of sombody who was talking at a bar about this blackout experience they had where they don't remember this one period in their life. And it turns out that this person at the bar is actually the computer project. All his experiences are being piped in from the outside. All his internal "feelings and everything else were being simulated inside the computer. He didn't know that he was the computer, however. One of iry motivating interests was to understand enough about the brain to be able to build one. ER: So you were obviously thinking about things like that before you wrote the story? ER: Right. That's something that had been in ny mind all through high school. I don't know how far back. You know, everybody is curious about what makes their brains tick in terms of psychology. I learned a little bit about brain cells, not very much, but enough to know that there was some sort of pattern of activity. So the natural question is, can you build one? If it's just a machine, you should be able to build one. But at the time, back in the '60s, the standard of computing was prehistoric compared to what we have today. I imagined it would take a whole surface of a moon or a planet. Can you imagine vacuum tubes back as far as you can see? So the technology has changed, but it is basically the same idea. Page 3 Terry Sejnowski 18 December 1996 ER: So you went to Case Western. What did you major in? TS: I was a physics major, I finished top of the class in physics, I went on to Princeton for graduate school because I wanted to work with John Wheeler in relativity, I worked with him for a couple of years, I was part of his group working on little projects during the period that black holes became a legitimate scientific enterprise. He had coined the term. Before that it was considered a singularity in the equations which was unphysical. John Wheeler has a very physical imagination and said, "Well, what if they exist in the universe, what would they look like?" So we were doing calculations about what would happen if the black hole was in the middle of a galaxy. What would happen if there were little black holes in the middle of the earth? What are the astrophysical consequences of this very esoteric, mathematical result? I worked with him for a couple of years. ER: What had led you to choose physics to begin with? TS: I guess I had always been interested in science, and physics seemed to me to be the most basic area of science, that all other areas grew from. And I was good at it, I remember when I had to choose my major when I was a sophmore, I asked a junior, I said, "Well, why did you pick physics, as opposed to metallurgy or something?" And he said, "Well, what other choice is there?" And that convinced me. Page 4 Terry Sejnowski 18 December 1996 Physics was very attractive, very intellectually exciting. I was the best in all the physics classes. I always had grades on tests that were two standard deviations above the mean. If the average of the class was thirty, I was the guy who had 60, So I had some talent for it. As it turned out, it was a wonderful education for a whole lot of other things too. Even though I'm not using a lot of the physics knowledge, it turns out that for what I'm trying to do now, which is to marry basic neurobiology with neural networks, it helps both with the experimental side because I know electricity and with physiology on the computers, which is what you need to take data. I also know the mathematics that you need to understand networks. It's turned out to be the ideal background. You know if I'd planned it, I couldn't have planned it better. ER: So you said you were in Wheeler's group for a couple of years and working on the black holes. ER: Right. They have general exams at Princeton where you are required to master all areas of physics and demonstrate that in a week long test. It's just one exam after the other. So you had to cram all that into your head, at least for a week. But I remember the summer before. Instead of studying for these exams, I went to the library and I picked up some books called the Josiah Macy conference proceedings on early cybernetics. But it was more than that, because Margaret Mead was there, Norbert Wiener was there, Gregory Bateson, and some really wild people. What was Page 5 Terry Sejnowski 18 December 1^96 interesting was the feeling that was generated back then. The excitement that we're on the verge of understanding something basic about the brain, and about how the control systems in the body work and it's maybe related to some psychological phenomenon that somebody there was studying. That was from the '50s and I remember following through and looking, and there were a whole spate of conference proceedings then. There was "Organization of the Mind," this Teddington conference. The British had these meetings going and then there were big American meetings. Self organization was big. So I spent the summer reading these books and then realized two things. One, that nothing ever came of it. That is there was all this excitement and it seemed to peter out. And second, cybernetics became splintered into a lot of mainstream things like control theory and signal processing and so forth. That became standard engineering discipline, but all the exciting parts died out. That was at least the impression from reading the literature, without talking to anybody. I went to somebody in biology because I wanted to know what had happened since then. And I don't know who it was, but somebody, a post doc probably, said, "Oh, Hubel and Weisel have done some interesting things. Why don't you go and look up some of their papers." i Page 6 Terry Sejnowski 18 December 1996 At the time, I desparately wanted to know the answer to one question. That is, do neural cells fire in a regular sort of clock-like fashion, at a fixed clock rate? Or was it more random, was there a stochastic component to it? She said if I read Hubel and Weisel's papers I would find the answer to that question. So I went to the library and looked up one of their papers in J. Physiol. I think in retrospect it was probably the '62 paper because that's one of the few papers you can go to where they actually give raw data. And lo and behold, sure enough it was random. [This classic paper, D.H. Hubel and T.N. Wiesel, 1962, Receptive fields, binocular interaction and functional architecture in the cat's visual cortex. Journal of Physiology, v. 160, 106-164, is one of the most cited papers in science.] Then I started taking some courses in the Psychology department because I'd discovered that Charlie Gross was there. He was giving a graduate seminar in vision and he records from different parts of the visual cortex, a la Hubel and Weisel, but much farther up. That was fascinating, because I got a chance to catch up all the work that had been done in vision since the early '60s. This was back in the early 1970s. That had a big impact on me, discovering the classical vision literature. JA: Was there anyone at Princeton you talked to about these issues? 1 Page 7 Terry Sejnowski 18 December 1996 TS: I had a lot of really wonderful mentors at Princeton. In addition to Charlie Gross as a teacher, I spent at least a siimmer in his lab actually participating in experiments. So that was hands on experience and it verified my surmise from the papers that there was an enormous amount of random component to the firing rate of the neuron in the visual cortex, especially in inferotemporal cortex, where Charlie Gross was looking at higher order visual neurons.