Electrodes

I have never understood correctly what electrodes are.

An electrolysis is a passage of direct current through an ion-conducting solution, producing a chemical change at the electrodes.

Then a mild electrical current sent through electrodes on the volunteers’ scalp caused the brain to suppress signals that affect the inner ear.

Cheok said different tastes are triggered by molecules that cause chemical ionization on the surface of the tongue, sending the brain electrical signals of a specific amplitude and frequency that are possible to reproduce with two electrodes.

To obtain the sound-stimulated brainwave patterns, Pasley used a device called an electroencephalograph, which measures the electrical firing of the patients' auditory circuits through electrodes already implanted in the patients' brains when they hear spoken words.