So I make my surfaces out of patterned gold. I then have to make sure my brain cells will be happy living on them using different surface chemistry. When I know they’ll be happy I put my brains on them and leave them in an incubator a few weeks to mature and settle. When they’re ready I put them on my microscope, take a tiny pipette and insert it into the brain cell. I then stimulate the cells (put small amounts of current in to make it active) then I record the light intensity changes using a camera.