Starting cognitive neuroscience in Argentina

The aim of the HFSP postdoctoral fellowship scheme is to identify future scientific leaders. This means not only the support of productive postdocs but of those who go on to have major impacts in their scientific careers. Former HFSP Fellows who return to countries other than the main scientific powerhouses face special problems. In this article, former HFSP Fellow and Career Development Award holder, Mariano Sigman, charts his path to establishing a new, world class, interdisciplinary cognitive neuroscience group on his return to Argentina.

About the author: Mariano Sigman was born in Argentina and grew up in Barcelona, Spain.  He obtained his PhD in neuroscience at Rockefeller University, working on visual perception and perceptual learning.  He went with an HFSP postdoctoral fellowship to Paris to the laboratory of Stanislas Dehaene before returning to Argentina, where he was successful in obtaining an HFSP Career Development Award. He obtained an HFSP Program Grant in 2007 in a team led by Stanislas Dehaene. He is now Director of the Integrative Neuroscience Laboratory at the University of Buenos Aires, Argentina.

On January 1st 2001 I was in Aguas Calientes (north of Jalisco, south of Zacatecas) celebrating the new year in the cheerful and colorful Mexican style. At this time, Argentina, my home country was all over the news. It was undergoing one of the most dramatic political and economic crises of the 21st Century with presidents changing almost every other day, major riots in the city of Buenos Aires and an entire country which had literally defaulted on its public debt.

Two years later, in January 2003, an HFSP fellowship took me from New York to Paris to do a postdoc with Stanislas Dehaene and in January 2006, from Paris to Buenos Aires. I was 33 years old, 20 years of which I had lived in Barcelona, Paris and New York. On coming back home, a distorted and blurred past inevitably meets the present. Only seven years after the riots I arrived in a country growing at a fabulous pace and with a national project for promotion of the development of science.

I came back to start a project which, due to several geographical and historical peculiarities, was in  a field completely unrepresented in Argentina. In Buenos Aires, one of the capitals of psychoanalysis, fields such as experimental psychology, cognitive neuroscience and even systems and dynamical neuroscience were rare creatures in academic circles. A tremendously dominating psychoanalytic influence in psychological education and a strong historical bias in neuroscience towards microscopy and static investigation (the Ramon y Cajal school) had created a major gap in our country between the science of the brain and the science of thought.

Returning to Argentina I discovered in viva presentia what we all know: that science, an intrinsic human and social activity, is not merely the construction of abstract knowledge (papers). My project was going to go somehow beyond the typical (and already challenging) foundation of a lab. It was going to be about seeding, in my country, a form of interdisciplinary thinking that was mainstream in many universities where I had worked,  but which was still seen here as a provocative enterprise.  

In 2007 I received a Career Development Award (CDA) from HFSP to support my research while building my lab. The main topic of this award was to understand how basic operations are chained and organized into mental programs. During these years we discovered that slow human computations (archetypically arithmetic thought) involve specific mental operations which are characterized by: 1) Flexible routing of information across different neural processors1; 2) emerging as a consequence of a routing architecture which exerts inhibition to avoid conflict in the routing process and with slow ignition process due to the basic biophysical properties of receptors2, 3; 3) hence involve a basic structural feature of cognitive architecture which cannot be overcome even with extensive practice4; 4) typically relate to conscious access positing that seriality is an intrinsic landmark of conscious computations5-8; and 5) can be then used to probe awareness in vegetative state patients (or in babies and non-numan primates as we are currently investigating) where verbal responses are not possible9, 10. We were able to synthesize these findings, outlining a theory of how individual neural processing steps might be combined into serial “programs”, which could narrow the gap between psychological theories of mental programs and neurophysiological research3, 11. Our hypothesis was that each step involves massively parallel accumulation of evidence and competition resulting in the selection of one out of many possible actions, including “overt actions” but also purely internal memory changes12. Crucially, the ability to nest operations that flexibly link sensory, mnemonic and motor components of thoughts confers the architecture a Turing-universal property.

Beyond this principal project, maybe because the ground was so open (or maybe because of an intrinsic lack of focus) my group has also been involved in a broad number of themes.  Just to name a few: neuroscience and education (we discovered a remarkable persistence of erroneous beliefs in mathematical foundations which are conserved from ancient Greece to modern times13), the observation that semantic associations form a Levy-Flights (diffusion with very large jumps)14, identifying spontaneous association between tastes and musical forms, bridging music and semantics15, measuring the price of time, investigating errors in decision making and policies for time budget using large-scale chess corpus as a goldmine for human experimentation16, 17, the rules and mechanisms of the construction of subjective confidence8 and understanding that the autistic mind organizes in a “big world” structure18. Our group has also recently developed the first laboratory of cognitive development, investigating when, how and why young infants learn. We have built what is probably the first fluent and persistent relationship with Buenos Aires hospitals9, 19, 20 to conduct neuropsychological investigation. We collaborate with magicians in Buenos Aires investigating rules of perceptual saliency and agency, and have even formed a small group to investigate the psychology of sexual preference and choice.

I arrived five years ago to a small space in a basement, in the far end of the Nonlinear Dynamics laboratory of the Physics Department.  We were a group of two: Juan Kamienkowski my first PhD student and myself, and this was about half of the entire computational and cognitive neuroscience community in Buenos Aires.  The greatest difficulty to start an independent project is that Argentinean funding agencies usually restrict significantly the funds to be used as "start-up”. This leads to a system with significant inertia where researchers come back to grow in already existing labs. In my case this was impossible because there simply wasn't a systems and cognitive neuroscience laboratory where I could come back to and use as a scaffold to launch my laboratory. Looking back after five years I see a rolling and growing number of students and postdocs who have virally formed a solid field of cognitive and computational neuroscience in Buenos Aires.  There are now about 25 members in our group. Students from the laboratory are now pursuing their careers in leading neuroscience laboratories in Europe and in the US and the impact of our laboratory has gone well beyond strictly academic circles.

I want to express publicly my infinite gratitude to the Human Frontier Science Program for their funds, which came at just the right moment and, most importantly, full of freedom and support, encouraging us not to stay in the comfort of well-trodden paths. The HFSP has promoted all forms of movement: geographical, intellectual, disciplinary. I can see how they shaped my path and I fully recognize the merits of the influence they have had on the early stage of my career and promoting the development of cognitive neuroscience in Buenos Aires.

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References

1. Sigman, M. & Dehaene, S. Brain mechanisms of serial and parallel processing during dual-task performance. J Neurosci 28, 7585-98 (2008).

2. Zylberberg, A., Dehaene, S., Mindlin, G. B. & Sigman, M. Neurophysiological bases of exponential sensory decay and top-down memory retrieval: a model. Front Comput Neurosci 3, 4 (2009).

3. Zylberberg, A., Fernandez Slezak, D., Roelfsema, P. R., Dehaene, S. & Sigman, M. The brain's router: a cortical network model of serial processing in the primate brain. PLoS Comput Biol 6, e1000765 (2010).

4. Kamienkowski, J. E., Pashler, H., Dehaene, S. & Sigman, M. Effects of practice on task architecture: Combined evidence from interference experiments and random-walk models of decision making. Cognition 119, 81-95 (2011).

5. Marti, S., Sackur, J., Sigman, M. & Dehaene, S. Mapping introspection's blind spot: reconstruction of dual-task phenomenology using quantified introspection. Cognition 115, 303-13 (2010).

6. Marti, S., Sigman, M. & Dehaene, S. A shared cortical bottleneck underlying Attentional Blink and Psychological Refractory Period. Neuroimage (2011).

7. Corallo, G., Sackur, J., Dehaene, S. & Sigman, M. Limits on introspection: distorted subjective time during the dual-task bottleneck. Psychol Sci 19, 1110-7 (2008).

8. Graziano, M. & Sigman, M. The spatial and temporal construction of confidence in the visual scene. PLoS One 4, e4909 (2009).

9. Bekinschtein, T. A. et al. Classical conditioning in the vegetative and minimally conscious state. Nat Neurosci 12, 1343-9 (2009).

10. Bekinschtein, T. A., Moos Peeters, D. S., Shalom, D. E. & Sigman, M. Sea Slugs, Subliminal Pictures, and Vegetative State Patients: Boundaries of Consciousness in Classical Conditioning. Frontiers in Psychology 2 (2011).

11. Zylberberg, A., Dehaene, S., Roelfsema, P. R. & Sigman, M. The human Turing machine: a neural framework for mental programs. Trends Cogn Sci 15, 293-300 (2011).

12. Gilbert, C. D. & Sigman, M. Brain states: top-down influences in sensory processing. Neuron 54, 677-96 (2007).

13. Goldin, A., Pezzatti, L., Battro, A. & Sigman, M. From Ancient Greece to Modern Education: Universality and lack of generalization of the Socratic Dialog". Mind Brain and Education (In Press) (2011).

14. Costa, M. E., Bonomo, F. & Sigman, M. Scale-invariant transition probabilities in free word association trajectories. Front Integr Neurosci 3, 19 (2009).

15. Mesz, B., Trevisan, M. A. & Sigman, M. The taste of music. Perception 40, 209-19 (2011).

16. Sigman, M., Etchemendy, P., Slezak, D. F. & Cecchi, G. A. Response time distributions in rapid chess: a large-scale decision making experiment. Front Neurosci 4, 60 (2010).

17. Slezak, D. F. & Sigman, M. Do not fear opponent: sub-optimal changes of a prevention strategy when facing stronger opponents. Journal of Experimental Psychology: General (In Press) (2011).

18. Barttfeld, P. et al. A big-world network in ASD: dynamical connectivity analysis reflects a deficit in long-range connections and an excess of short-range connections. Neuropsychologia 49, 254-63 (2011).

19. Petroni, A. et al. The cortical processing of facial emotional expression is associated with social cognition skills and executive functioning: a preliminary study. Neurosci Lett 505, 41-6 (2011).

20. Ibanez, A. et al. Cortical deficits of emotional face processing in adults with ADHD: Its relation to social cognition and executive function. Soc Neurosci 6, 464-81 (2011).