In the early 20th century, electrical recording of the brain impulses was developed. A sensitive voltmeter was initially used to measure the electrical activity of neurons.
The three technical tools used by scientists to measure the neuronal electrical activity are,
• Recording from the giant axon of the Squid
• Using oscilloscope to measure voltage changes
• Crafting microelectrodes to fine enough to locate on an axon
Thus, the blanks can be filled with, recording from the giant axon of the Squid; using oscilloscope to measure voltage changes; crafting microelectrodes to fine enough to locate on an axon.