What is EEG?

Electroencephalography is the neurophysiologic measurement of the electrical activity of the brain by recording from electrodes placed on the scalp or, in special cases, subdurally or in the cerebral cortex. The resulting traces are known as an electroencephalogram (EEG) and represent a summation of post-synaptic potentials from a large number of neurons. These are sometimes called brainwaves, though this use is discouraged, because the brain does not broadcast electrical waves.The EEG is a brain function test, but in clinical use it is a "gross correlate of brain activity". Electrical currents are not measured, but rather voltage differences between different parts of the brain.

The basic knowledge above comes from Wikipedia. It can give you a concept: EEG is a kind of signal from brain.

There are some details about the EEG data in our lab in Nankai University.

Some of the EEG data come from brains of human beings, including epileptic EEG signals from patients in hospitals, EEG from healthy people and ERP (Event Related Potentials) raw data from cognization research centers. Most of these signals have been collected in a database, you can see the articles with the tag database for more introduction.

Some EEG data were obtained from rats, which were healthy or in ill condition (ischemia model or epilepsy model). Signals from animals may be much more easier for us to detect the things happening in the brain. We recorded the data from the hippocampus and also the cortex.

Obviously, our purpose of calculating these data is to investigate the brain and to find out different features in the nerve systems in different physiology conditions. The analysis methods will be discussed in other articles.