Neurons in the brain signal to each other with tiny electrical blips, about 1/1000^th of a second long and 1/10^th of a volt high.  These “action potentials” are the internal language of the nervous system, yet they are no more visible to the eye than are the electrical signals carrying a conversation down a telephone wire.  Neuroscientists have long sought techniques to convert these electrical impulses into light.

We discovered that a transmembrane protein derived from a Dead Sea microorganism can function as a fluorescent indicator of membrane voltage.  Upon expressing this gene in a neuron, action potentials manifest as flashes of fluorescence.  We are developing sophisticated optical systems to image brain activity in cultured neurons and in vivo, and software to interpret the torrents of data that result.  We compare these measurements to quantitative models of brain function.

The lab also explores bioelectric signaling outside the nervous system: in cardiac cells, in blood cells, and even in bacteria.  We are interested to explore electrical dynamics in places where electrodes have been unable to reach, such as in cellular organelles.