The above set of images (on the left) represents a three frame sequence of the drug-induced expansion of a growth cone from an Aplysia neuron. The corresponding graphics (on the right) represent the inner and outer edges of the lamellipodium, or neuronal membrane. The four sided polygons are tracked over the sequence and used to illustrate how the membrane deforms. Analysis of single polygon vertices also provides a measurable notion of strain present. (Thanks to Drs. R. Knox and L. Jonas of the Dept. of Pharmacology for the images).