Mathematical Biology Seminar German Enciso Department of Systems Biology, Harvard University Friday Jan. 11, 2008 3:05pm in LCB 215 "Motion in the right direction: a model of direction selectivity in the retina " Abstract: A neuron in the retina called a directionally selective ganglion cell (DSGC) has long been known to fire a signal only when it detects a light stimulus moving towards a specific direction. It has been a largely open problem for the past 40 years to determine the mechanism behind this 'direction selectivity', which is now believed to involve neighboring radially symmetric neurons called starburst amacrine cells (SAC). After giving a general introduction to the subject, I will describe a tentative computational model for this process using a tightly interconnected, compartmental network of SACs. I will discuss the ability of this model to reproduce basic experimental measurements, and I will consider the interplay among several stimulatory waves as a possible explanation for this behavior. A similar model will consider the propagation of a wave of inhibition in the SAC network. This work has been carried out in collaboration with David Terman at MBI and the Stuart Mangel lab at the Ohio State University Neuroscience Department.