The Faculty

Focus

Elucidating the molecular and neural bases of sleep behavior conserved across phyla

Education

Hebrew University, Jerusalem, Israel, B.Sc., 1993-1996, Physics and Computer Sciences

Hebrew University, Jerusalem, Israel, M.Sc., 1997-1998, Physics

Weizmann Institute of Science, Rehovot, Israel, Ph.D., 1999-2004, Biophysics

Harvard University (Cambridge) and Brandeis University (Waltham), MA, Post-Doc, 2004-2008, Neuroscience, Behavior

Honors

1996 Magna Cum Laude, B.A. Physics and Computer Sciences

1997 Intel-Dean Prize

1998 Magna Cum Laude, M.Sc. Physics

2003 Menashe Millo Memorial Prize

2005 Rothschild Fellow

2006 Howard Hughes Medical Institute Interfaces Scholar Award in Quantitative Biology

2005-08 Human Frontiers of Science Program Cross-Disciplinary Fellow

2008-present Burroughs Wellcome Fund Career Award at the Scientific Interface

2010-present Searle Scholar Award

Research Interests

All living organisms obtain information about their environment, process it and respond with behavioral output. Often, but not exclusively, information processing is performed by networks of neurons in the brain. However, studying complex brains is extremely challenging both conceptually and technically. Fortunately, some model systems exhibit non-trivial behavioral patterns that are governed by neuronal circuits of limited size. A handful of such identifiable neurons are ideal for a detailed scrutiny on multiple levels: from circuitry to individual molecules within a single cell. These small systems can potentially facilitate an understanding of basic principles of neural information processing and the regulation of behavior. In other words, it can be reasonably argued that C. elegans is a promising candidate for the title "the phage of neuroscience" (or "the hydrogen atom of neuroscience", if you will).

The nematode C. elegans possesses 302 neurons, the anatomy and connectivity of which are known with great precision. It was the first multi-cellular organism to have its genome fully sequenced and many of its genes have been cloned and characterized. Furthermore, a slew of existing genetic, genomic and biophysical techniques make it possible to perturb and assay this model organism with unparalleled experimental resolution. Specifically, it is possible to study concurrently the behavior of the entire animal, sub-circuits in its nervous system, individual neuron physiology and the molecules involved in intra-neuronal signaling pathways.

In broad strokes, the goal of our research is to contribute to a collective effort to truly understand small networks of neurons. Asymptotically, we identify this sought-after understanding with the ability to answer all of the questions about the system that might come to mind. These questions span multiple scales and various degrees of abstraction, from the molecular components of the system to the engineering and ingenuity of computing biological networks. This challenge must be met with a parallel effort of both forward (e.g., revealing the molecular components and their interactions in detail) and reverse (e.g., systems analysis of higher function and statistical properties) approaches. Such detailed scrutiny is likely to spawn theoretical insights. It is our hope that these, in turn, will transcend the boundaries of small neural circuits and contribute to the thinking about more complex neural networks. At the same time, we believe that explaining small neural circuits is a worthy challenge in its own right.

Lethargus: the sleep-like behavior of the worm

Little is known about the regulation of the absence of movement, yet behavioral quiescent states are universal to the animal world with the most famous of these being sleep. It was recently discovered by David Raizen et al. that a C. elegans behavior termed lethargus bears behavioral similarities to sleep. We would like to contribute to establishing the nematode C. elegans as a novel model system for studying the genetic regulation of sleep. Is a novel, simple model organism for sleep genetics actually needed? Could C. elegans possibly be considered a potential model organism for sleep? We think that preliminary evidence suggests that this indeed may be the case - unequivocal proof is yet to be attained. It is currently unknown to what extent worms might be sharing sleep-regulatory mechanisms with more complex animals. In a nutshell, it is our job to help in finding out.

Selected peer-reviewed publications

  1. Iwanir S., Tramm N., Nagy S., Wright C., Ish D. and David Biron The microarchitecture of C. elegans behavior during lethargus: homeostatic bout dynamics, a typical body-posture and regulation by a central command neuron SLEEP (2013) 36:385-95 PMCID: PMC3571756
  2. Biron D., Wasserman S., Thomas J. H., Samuel A. D. T., and Sengupta P. An olfactory neuron responds stochastically to temperature and modulates Caenorhabditis elegans thermotactic behavior Proc Natl Acad Sci USA (2008) 105(31):11002-7 PMCID:18667708
  3. Chi C. A., Clarck, D. A., Lee S., Biorn D., Lou L., Gabel C. V., Brown J., Sengupta P. and Samuel A. D. T. Temperature and food mediate long-term thermotactic behavioral plasticity by association-independent mechanisms in C. elegans  J Exp Biol (2007) 210(Pt 22):4043-52 PMCID:17981872
  4. Biron D., Shibuya M., Gabel C., Brown A., Clark D.A., Wasserman S.M., Sengupta P. and Samuel A.D.T. Regulation of thermotactic behavioral plasticity by a diacylglycerol kinase in C. elegans Nat Neurosci (2006) 9(12):1499-505 PMCID:17086178
  5. Clark D. A., Biron D., Sengupta P. and Samuel A.D.T. The AFD sensory neurons encode multiple functions underlying thermotactic behavior in C. elegans J Neurosci (2006) 26:7444-51 PMCID:16837592
  6. Biron D., Alvarez E., Tlusty T. and Moses E. A Molecular Model of the Contractile Ring Phys Rev Lett (2005) 95:098102
  7. Biron D. and Moses E. The effect of -actinin on the length distribution of F-actin Biophys J (2004) 86:3284-90
  8. Biron D., Libros P., Sagi D., Mirelman D. and Moses E. Midwifes assist dividing amoebae Nature (2001) 410(6827):430