Billions of nerve cells work together in the brain to coordinate sensory input, thoughts, and emotions at any given moment. The nerve cells communicate with each other by means of electrochemical transmission. Electroencephalography (EEG) makes it possible to record the electrical activity of clusters of nerve cells as reflected in changes in electric potential at various locations on the scalp.
EEG was the first noninvasive technique developed to measure brain activity. It can be used on people who are sleeping, resting, or performing tasks in the lab. Thanks to the method’s high temporal precision (with a resolution of under 1 ms), it remains indispensable both in clinical settings and in experimental research on healthy study participants.
There are four measuring cabins in the EEG laboratory at the MPI for Human Development. Each cabin is shielded against both sound and electromagnetic radiation to ensure that the EEG measurements are as free of interference as possible. A modular amplifier system allows EEG recordings of high spatial resolution (32–128 channels per participant). Further systems for simultaneously recording other biosignals are also available. For example, an electrocardiogram (ECG) can be used to monitor the activity of the heart or an electromyogram (EMG) to measure muscle activity. Respiration, skin conductance, and pulse may also be measured depending on the experiment. A system for the three-dimensional localization of electrodes allows the position of the electrodes on the head to be determined with millimeter precision. In combination with structural magnetic resonance imaging (MRI), it is thus possible to precisely reconstruct the electrical activity of the brain.