The first thing to understand about the brain is the organization of electrical activity in relation to time. The discovery of bioelectricity is generally credited to Luigi Galvani (1780), although it was known before that. Galvani connected a battery to a frog's legs and made them twitch. Fast forward 140 years till Hans Berger (1924), who is credited with discovering the EEG, although again it was known before that.

Traditionally, we "record" electrical activity with electrodes, and we can also "stimulate" the brain electrically and magnetically. But these methods are rather crude, since electrodes are usually much larger than neurons and synapses. There are physical models for how electromagnetic signals are conducted in the brain (like "volume conduction", which is used to map current sources for the EEG), but we don't really know how time is organized, so we don't know what they mean. Let's see if we can begin to understand how time is organized in the brain.