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Cardiff University Brain Research Imaging Centre

Electroencephalography labs

Watch a video about electroencephalography

We have three dedicated Electroencephalography (EEG) laboratories where we carry out cutting-edge brain research.

How EEG works

Electroencephalography (EEG) is a non-invasive technique used to monitor the electrical activity of the brain. Each individual neuron has an electric potential, but this is far too small to be detected by EEG. Therefore, EEG activity represents the summation of millions of neurons that fire together and are of a similar spatial orientation. The activity we see in the EEG is thought to reflect predominantly pyramidal neurons.

EEG is often performed by applying an elastic cap with electrodes embedded in it to the participant's head. The electrodes are attached to the scalp to record minute electrical activities (down to microvolts). These minimal activities can be amplified, digitised and recorded by a computer for further analysis. EEG is a safe and non-invasive way of measuring brain activity.

This picture shows an example of continuously recorded EEG signals. On a light blue background, tens of horizontal black lines fluctuate across time from left to right. The fluctuation of each line represents the amplitude fluctuation of the signals being picked up by the EEG electrodes placed on the scalp. Two vertical lines overlaying the signals of all electrodes represent two triggers sent to mark the time point of stimuli being presented.
An example of continuously recorded EEG signal: the horizontal axis represents time and the vertical axis represents amplitudes. The fluctuation of each line represents the amplitude variation of the signals being picked up by the electrodes. The two vertical lines represent the time points of the stimuli being presented.

Applications of EEG

EEG is useful for both research and clinical applications. It has been widely used to investigate research questions in cognitive neuroscience and psychology. With appropriate experimental designs, the excellent time-resolution of EEG (down to even shorter than 1 millisecond) can be used to investigate various cognitive functions such as: attention, perception, auditory processing, motor preparation, language, and memory.

Woman attaching an EEG cap and electrodes to a male study participant's head
An EEG cap and electrodes are attached to a participant's scalp before testing.

EEG facilities

We have three EEG labs and one preparation room with dedicated washing facilities. All the labs are equipped with BioSemi ActiveTwo systems, and a passive Brain Vision Quickamp system from Brain Products is also available upon request. All three labs are also equipped with computers which can present stimuli and collect responses from participants via keyboards or response boxes, together with their EEG activity.

The BioSemi ActiveTwo systems are capable of recording up to 128 channels with sampling rate ranges from 2048 to 8192 Hz. The Brain Vision Quickamp system is capable of recording up to 128 channels with sampling rate ranges from 125 to 2048 Hz. Caps for both systems are also available in a range of sizes (52-62 cm). Matlab (Cogent and Psychtoolbox), E-Prime and PsychoPy are available in the labs. Other presentation platforms are available upon request.

EEG recording can also be used simultaneously with MRI, MEG or Brain Stimulation techniques, as well as for sleep studies and developmental studies.

In addition to the EEG systems, we also have a Polhemus Fastrak digitiser system for digitising electrode locations and head shapes. The location information of the electrodes can facilitate studies using source localisations.

Find out more about our EEG equipment.

Apply to use our facilities.