I will explore how the small “spines” that protrude from a neuron’s dendritic branches handle electrical information. Neurons are structurally complex: most have a single long axon that transmits electrical signals and multiple branching dendrites that receive input from neighboring cells. For many neurons, these dendrites are additionally covered in small spines that integrate incoming information. Although alterations in the shape or number of dendritic spines are implicated in disorders such as autism and schizophrenia, little is known about whether these structures have a specialized role in transmitting electrical information independent from their associated dendrite. The Yuste laboratory has developed a method that uses voltage-sensitive fluorescent proteins to measure the electrical activity of dendritic spines in neurons grown in the lab. Now, combining this approach with state-of-the-art techniques in molecular genetics, neurophysiology, and microscopy, I will track the electrical activation of dendritic spines in the visual processing center of a mouse brain in response to a flash of light or to artificial stimulation. I will then shut down the sodium channels that activate neurons to assess their involvement in dendritic spine activity. Results from this work could provide new therapeutic targets for a variety of neurological conditions.