Scans Scientists have long wondered how we manage to remember smells despite the fact that each olfactory neuron in the epithelium only survives for about 60 days, to be replaced by a new cell. In most of the body, neurons die without any successors. But as the olfactory neurons die, a layer of stem cells beneath them constantly generates new olfactory neurons to maintain a steady supply. And so some stages of olfaction are beginning to yield to researchers. But many mysteries remain.
Some researchers believe that such questions can best be answered by studying the salamander.
This lizard-like creature' s nasal cavity is a flattened sac. To study the entire system non-invasively, Kauer uses arrays of photodetectors that record from many sites at once. He applies special dyes that reveal voltage changes in the membranes of cells. Then he turns on a videocamera that provides an image of activity in many parts of the system. This would be amazing progress for a sensory system that was virtually unexplored five years ago.