Measuring neuronal electrical activity

A very sharp microelectrode, guided under a microscope, can be inserted inside a single neuron to measure electrical activity in the cell. This is easier to do in animals like Aplysia with large neurons.

The electrical activity of neurons is usually viewed as a real-time moving graph of voltage on the y axis and time along the x axis. In the videos that follow, the graph is about 100 mV tall by about a half second long.