Portal de Periódicos da CAPES

Asif Ghazanfar

2016; Elsevier BV; Volume: 26; Issue: 24 Linguagem: Inglês

10.1016/j.cub.2016.10.049

1879-0445

Asif A. Ghazanfar,

Neuroscience, Education and Cognitive Function

Asif Ghazanfar is Professor of Neuroscience and Psychology and an associated faculty member in Ecology and Evolutionary Biology at Princeton University. Born in Washington state and raised in neighboring Idaho, he graduated with a philosophy degree from the University of Idaho, then went on to earn his PhD in Neurobiology from Duke University under the guidance of Miguel Nicolelis. After that, he did postdoctoral work with Marc Hauser at Harvard University and was then a research scientist in the lab of Nikos Logothetis at the Max Planck Institute for Biological Cybernetics in Tübingen, Germany. He enjoys being a scientist immensely and could not be happier. His research focuses on the biology of vocal communication in primates and if one insists on labeling him, his preference would be ‘integrative biologist’ but he would be okay with ‘neuroethologist’. Did you always want to be a biologist? No. From the ages of 10 to 19, all I wanted to be was a virtuoso rock guitarist — the next Steve Vai or Joe Satriani. But I’ve been interested in biology for as far back as I can remember. I was always collecting spiders, insects, snakes and other creatures. I had hamsters and gerbils as pets and a close childhood companion of mine was my cat, Charlie. During family dinners, the TV was often on and tuned to wildlife shows. So, I guess, my interest in biology gradually just became a part of who I was and not something that initially came to mind as a career choice. As you might imagine, my dad wasn’t thrilled with my obsession with the guitar and, by the time I was in high school, he was relentless in his attempts to steer my interests and ambitions towards medical school. Two other things also happened around this time. First, my teachers were increasingly encouraging about my aptitude for science and, second, I realized that I just didn’t have the discipline to become a virtuoso musician. By the end of my first year of college, I knew I wanted to study biology for the rest of my life. My favorite course was Developmental Biology and I remember loving it so much that I read the textbook cover-to-cover twice! However, I ended up majoring in philosophy because I was enamored with the idea that all of science originated in philosophy. More practically, the requirements for a philosophy major were loose enough that I was able to take all the courses in biology and psychology that I wanted while avoiding courses in botany that I dreaded and were required for a biology degree. How did you get interested in neuroscience in particular? My fascination with the brain and its evolution probably started when I read a popular book by Carl Sagan entitled “The Dragons of Eden”. One of the captivating ideas it presented was the ‘triune’ brain theory (now thoroughly debunked). This was a model of brain evolution put forth by Paul MacLean that argued that our brains have an ancient reptilian core that controls basic survival functions, a paleomammalian complex (the limbic system) which controls emotions, followed by a neomammalian neocortex which controls rational thought. He suggested that these different systems evolved on top of each other in a sequence over the course of evolution. It sounded super cool at the time. Because I was still being pushed towards medical school and knew that getting ‘research experience’ would look good on my application, I sought work in a lab. My first experience was to culture bacteria, extract their DNA and then amplify certain sequences using PCR. I had no interest in studying biology at that level and, frankly, I’m not sure how I ended up in that lab. I think I just asked around to see who was looking for help. The next time around, I was more proactive and sought a professor who was actually doing neuroscience. There was one, Mark DeSantis. I just accosted him in his office and asked if I could work in his lab. He was enthusiastic! We started a project together looking at motor neuron development in the rat spinal cord. Mark showed me how to do immunohistochemistry, to section tissue, to look at it under a microscope, to take photomicrographs and develop them into slides, and to present the data at a conference. He really took me under his wing. Around the same time, I started reading more serious books on neuroscience on my own as there were no neuroscience classes at my university. This was the early 1990s and the ‘Decade of the Brain’ was just underway. Few small schools at that time had neuroscience departments. I read whatever few neuroscience books were on offer at our small bookstore. The first was “The Foundations of the Neuron Doctrine” by Gordon Shepherd; the second was “Body and Brain” by Dale Purves (an absolutely lovely book that I’ve read more than once and still consult frequently); and the third was “Stress, the aging brain and the mechanisms of neuron death” by Robert Sapolsky (probably because ‘neuron death’ sounded cool to me at the time). This led me to the next lab I worked in and that kind of became a home for me, intellectually and personally. Matthew Grober, a charismatic New Yorker, had just arrived at the university and was starting his lab. He studied the mechanisms of sexual plasticity using sex-changing fish as a model system. In the social system of this fish, if the dominant male dies for whatever reason, one of the females changes sex to take his place. A number of hypotheses to explain the mechanisms needed for this massive anatomical and physiological transformation have been proposed, including ones invoking roles for stress, neurogenesis and neuron death. The Grober lab framed its investigation of this incredible fish by addressing all of Tinbergen’s four question areas: evolution, development, function and mechanism. It was a really wonderful, formative experience to work in his lab. I also got to do some fieldwork in Hawaii, collecting female fish and treating them with testosterone to see if it was sufficient to get them to change sex. The appeal of taking an integrative approach to understanding behavior has stuck with me ever since as has my friendship with Matthew (I meet with him for breakfast in Atlanta almost every year). How did you get from there to studying communication in monkeys? I was certain that I was going to study brain development in graduate school. My top choice program was in the newly formed Department of Neurobiology at Duke University, because they had at least three faculty studying neural development (including Dale Purves, who founded the department) and because it was very far away from Idaho. I was admitted and considered their top choice, too. The late Larry Katz relayed this to me via email (a print out of which I keep in my files). My admission to their program, and this email from Larry, meant a lot to me because I felt like an imposter coming from an unknown public university and trying to get into the ‘big league’. Though I was (and still am) in awe of neural development, I didn’t pursue it at that time. During my first year at Duke, a new faculty member arrived, Miguel Nicolelis, who was energetic and full of bold ideas. He, too, came out of unknown parts of academia (University of Sao Paulo, Brazil) and we hit it off immediately. He introduced me to neurophysiology and the pursuit of big ideas but, just as important, he showed me how to take data, analyse them and produce a paper. My dissertation was on corticothalamic neural ensembles in the somatosensory system of rats and, about two years into it, I knew I wanted to study something else. So while I was thoroughly enjoying graduate school and the Nicolelis lab, I was also thinking about how, after graduating, I could combine all the stuff that really interested me and pursue it in a way that was integrative. The summer before starting at Duke, I read Steven Pinker’s ‘The Language Instinct’, which opened up a new line of evolutionary thinking for me. The exciting idea driving this book-— that human language evolved just like any other phenotype — together with all my past experiences and interests led me to the conclusion that what I really should be studying is the mechanisms of primate communication. I envisioned using the same neuroethological approach that has been applied so successfully to studies of bats, frogs and birds; one of my goals was to show that monkeys are as just as specialized, behaviorally and neurally, as any other species and that they are not just smaller versions of humans. So how did you switch from rats to monkeys as a model system? It was quite easy. Pinker’s book refined my interests, but now I was looking for meatier sources of information. I read Marc Hauser’s just-released tome “The Evolution of Communication”; it provided a grand overview of animal communication organized around Tinbergen’s four questions. Like my undergraduate mentor, Matthew Grober (who’s a good friend of Marc’s from UCLA grad school), Marc seemed interested in biology at all levels (including neuroscience) and that really appealed to me. So, I wrote him explaining that I wanted to do a postdoc with him so that I could learn about primate vocal behavior and then use what I learned to motivate neurobiological investigations. I visited his lab, gave a talk and got the position. In Marc’s lab, I learned an incredible amount about behavior, experimental design, how to formulate good, falsifiable hypotheses and how to write a lot better. I worked with vervet monkeys, rhesus monkeys and cotton-top tamarins. I also got to do field work, something that I really wanted to combine with lab work. Marc Hauser was found guilty of scientific fraud: how did that affect you? Much has already been written about this so I won’t rehash it here. I was not much affected by it for two reasons. First, I had been in a faculty position for awhile at the time the accusations came to light. Second, none of my papers with Marc were part of any investigation. When I was in his lab he was very generous with his time. He would give extensive comments on manuscript drafts in under 48 hours (always), so I was never waiting long for feedback. Marc is a great writer so his comments certainly helped me become a better writer. He was very supportive in all the things others and I wanted to do and would find us opportunities to pursue them. How did you get from there to Germany? I had proposed to do some neurophysiology in my fellowship but the collaboration Marc had established to do this was not working out well for me. After about a year, I abandoned it and right around that time Partha Mitra (who was then a researcher at Bell Labs) visited the Hauser lab with an idea. He proposed going to Nikos Logothetis’ lab in Germany to do monkey auditory functional magnetic resonance imaging (fMRI) using conspecific vocalizations as stimuli. Nikos was just establishing his amazing facility to do fMRI work in monkeys and was receptive to the idea. Partha and I tried for two summers to get it to work. I was thinking this would be such an easy way to get cortical maps of conspecific vocalizations like the echolocation maps in the bat auditory cortex. This was pretty naïve. The MRI facility was run by a highly skilled group of technicians, so we thought all we had to do was to put together a stimulus sequence and find a way to deliver the sounds to the monkey’s ears in the midst of all the scanner noise. However, we could not get any meaningful activation of auditory cortex. That was a big disappointment, but being in Nikos’ lab for those short stints was eye-opening. Under his direction, absolutely everything there was done at the highest level. Everywhere in the lab looked like part of a space station, like the future of neuroscience was right there in front of you. I felt very out of place but I interpreted that feeling as a sign that my rate of learning would be very high if I joined his lab and that it would be great for my development as scientist. I wrote Nikos a long email explaining that what I wanted to do was auditory neurophysiology in his lab to establish a ‘neuroethology’ of primate vocal behavior (eschewing the pursuit of auditory fMRI). This was far afield from Nikos’ focus on visual neuroscience but, to my surprise, he enthusiastically gave me a chance. Not only that, he gave me a large amount of space to work in, a physiology rig all to myself and literally anything else I could ever need. It was a scientist’s heaven. I learned a huge amount about linking behavior to neurophysiology and signal analysis and, more generally, that there really is no getting around the value of hard work. The most important thing I learned in his lab (indeed, anywhere) was scientific rigor. Nikos showed me the importance of pursuing projects and analyses thoroughly and with the highest possible standards, to do your best to establish robust findings that will stand the test of time. Books seem to have an outsized influence on you throughout your career: what are your favorite books and papers? It’s hard to pick ‘all time’ favorites, but there are three books that are currently influencing my work quite a bit: “Rhythms of the brain” by Gyorgy Buzsaki; “How the body shapes the way we think” by Rolf Pfeifer and Josh Bongard; and “Individual development and evolution” by Gilbert Gottlieb. The papers that had the strongest influence on me were two that I read in graduate school: “The brain has a body” by Chiel and Beer (Trends Neurosci., 1997) and “Cortical activity flips among quasi-stationary states” by Abeles et al. (Proc. Natl. Acad. Sci. USA, 1995). The common theme among these books and papers is their sophisticated consideration of the brain, body and/or behavior as dynamical systems. How do you keep up with the literature? I don’t really keep up with the literature in the standard sense. I probably carefully read two or three papers a week and those are usually selected based on leads from the reference lists of papers I’ve read earlier and sometimes they are recommendations from lab members or colleagues. I tend to read just what interests me in the moment and it would seem to an outsider somewhat haphazard. This last week I read about morphological computation in robots, the connectivity of the visual word form area and the genetics of the arousal system. In my head, and in the types of project my lab pursues, these all fit together coherently. I’m just as likely to read something published decades ago as a recent study. What advice would you give someone starting a career in biology? I’ve been extremely lucky. I continue to have a very high level of excitement about the work that my lab does and the means to do it. I’ve benefited enormously from the generosity of my advisors throughout my career. All were incredibly supportive. I think the best advice I can give is to find a line of research that you feel very passionate about and stick with it. Skip the fads, forget about what is currently perceived as ‘hot’, and pursue questions that really interest you. To paraphrase Cornel West (who in turn paraphrased Martin Luther King, Jr.): It’s better to try to be a thermostat and shape the direction of science, than to be a thermometer that slavishly reflects it. Adopt techniques as the research questions call for them, not the other way around. Be humble and willing to learn from anybody, forget about hierarchies. Err on the side of being too generous with credit and authorship. Your relationships with your advisors and lab peers are life-long. Do your best to take care of them while not letting slavish ‘loyalty’ get in the way of the science. Finally, two other tips that I’ve heard that help keep me focused: first, you’re only competing with yourself; and second, you can’t be both popular and an iconoclast (I think this was said by Eve Marder to a good friend of mine who relayed it to me). I understand you have two little girls: do you hope they follow your footsteps and pursue careers in science? I am exceptionally lucky in that I truly love what I do. That is what I want for them — to be passionate about their work whatever that may be. I would be delighted if they decided to pursue science as a career, but I would be just as delighted if they decided to become virtuoso rock guitarists.