Look at the line on the computer screen. It's a record of the electrical impulses coming from the live sea slug brain in the dish below. Look through the magnifier to see the live brain. Notice the tiny glass electrode that has been inserted into the brain. The electrode is used to record the activity of, and sends signals to a single cell in the live brain. Push the button and turn the knob on the panel below to send impulses to the live brain cell. Each time you see a spike on the screen, it means the live brain cell in the dish below is firing an impulse. Your brain fires the same kind of impulses all the time, creating memories and thoughts. Push and hold the button while you turn the knob to signal the live brain cell to fire more impulses. Look at the computer screen to see the impulses.