Electroencephalography System (EEG)

Our lab is equipped with a dense array (128 electrode) electroencephalography (EEG) system (Net Amps 400) as provided by EGI. This system was chosen because it is among the most participant-friendly on the market and can even be used – without discomfort or risk – on babies. The nets are saline-based (e.g., uses damp sponges), which reduce application times to under 15 minutes. We have recording nets in several sizes, allowing us to do research on young children as well as adults.

EEG measures tiny changes in bioelectric fields picked up by electrodes that rest on the outside of your head. The signal is generated by the simultaneous activation of large amounts of organized (pyramidal) neurons from your brain. Due to the organized nature of the cortex, EEG is mostly sensitive to cortical activation. The strength of the EEG technique lies in its temporal resolution which allows researchers to measure changes in neural activation with a millisecond precision. Under the right experimental conditions, EEG activation can be related to subtle cognitive processes that occur within the blink of an eye. This makes EEG a unique technique to study neural activity underlying rapid cognitive processes such as response inhibition, attentional control, and decision making. EEG, however, is also used to study several mental processes ranging from working memory to language.

EEG Data Methods

Many analytical methods can be applied on EEG data (often conducted in MATLAB), such as:

Event Related Potentials (ERP)
ERP graph

ERP graph

ERPs represent averaged waveforms time-locked in response to a particular event. Within a particular experimental context, the latency and amplitude of certain ‘waves’ can relate to cognitive processes.

Brain Oscillatory Power
graph reading brain waves

Graph depicting estimate of power of specific oscillations related to cognition and behavior.

The brain is much like an orchestra with several neural populations firing synchronously with various different oscillations; some fast and some slow (in Hz). Using analytical techniques, we can estimate the power of (changes in) specific oscillations which relate to cognition and behavior.

Source Analyses
brain scan.

Brain activity scan.

Due to the high amount of electrodes in our system (e.g., 128 electrodes), we can also conduct a source analysis, which can provide a rough estimate of where in the brain activity takes place.