Aravinthan D.T. Samuel

Department of Physics
Harvard University
Jefferson Building, Room 349
17 Oxford Street, Cambridge, MA 02138

tel: (617) 384-9435

Research Interests

Brain and behavior in small animals
Our lab develops and applies new biophysical tools to probe neurophysiology and behavior in the nematode C. elegans and the Drosophila larva. These small, transparent, genetically tractable organisms are particularly amenable to optical methods to manipulate and monitor neural activity, and we have developed several technologies based on physical optics to interrogate their neural circuits.

For example, we helped develop ultrafast laser surgery in C. elegans, which now enables researchers to dissect the nervous system of the nematode with nanometer-scale precision, sufficient to snip individual nerve fibers without damaging collateral tissue. We also developed the first high-resolution tracking systems that allowed the quantification of single-neuron activity as well as optogenetic manipulation with single-cell resolution in freely moving animals. Importantly, the simple body plans and small repertoire of movements of C. elegans and Drosophila larva facilitate the accurate and comprehensive quantification of locomotory behavior based on time-varying posture. These technologies have allowed our lab and our collaborators to extract the sensorimotor transformations that build complex behaviors like chemotaxis and thermotaxis. By mapping these sensorimotor transformations to the workings of circuits, neurons, and molecules using optical neurophysiology, our laboratory has made several contributions to understanding of brain and behavior in these model organisms.

Selected Publications:

Clark, D.A., Gabel, C.V., Gabel, H., Samuel, A.D. (2007). Temporal activity patterns in thermosensory neurons of freely moving Caenorhabditis elegans encode spatial thermal gradients. Journal of Neuroscience 27:6083-6090.

Luo, L., Gershow, M., Rosenzweig, M., Kang, K., Fang-Yen, C., Garrity, P.A., and Samuel, A.D. (2010).  Navigational decision-making in Drosophila thermotaxis. Journal of Neuroscience. 30:4261-4272.

Ha, H., Hendricks, M., Shen, Y., Gabel, C.V., Fang-Yen, C., Qin, Y., Colon-Ramos, D., Shen, K., Samuel, A.D., Zhang, Y. (2010). Distinct neural circuits regulate switch of olfactory preference in Caenorhabditis elegans. Neuron, 68:1173-1186.

Leifer, A., Fang-Yen, C., Gershow, M., Alkema, M., Samuel, A.D. (2011). Optogenetic control with high spatial and temporal resolution in freely moving C. elegans. Nature Methods, 8:147-152.

Gershow, M., Berck, M., Mathew, D., Luo, L., Kane, E., Carlson, J.R., and Samuel, A.D. (2012). Controlling airborne cues during small animal navigation. Nature Methods 9: 290-296.

Pinan-Lucarre, B., Gabel, C., Hulme, S.E., Shevkoplyas, S.S., Slone, R.D., Xue, J., Weisberg, S., Whitesides, G., Samuel, A.D., Driscoll, M. (2012).  The core apoptotic executioner proteins CED-3 and CED-4 promote neuronal regeneration in Caenorhabditis elegans. PLoS Biology, 10:e1001331.

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