EEG is a functional brain research technique that records changes in electric potentials caused by neural activity. EEG is often recorded to study event-related potentials (ERPs) representing changes in brain activity when a certain stimulus is presented to the participant. EEG is typically measured with electrodes attached to the scalp. EEG offers a good temporal resolution, but exact sources of brain activity can be more challenging to interpret. It is a safe, cost-effective and easy method that is in heavy clinical and scientific use around the world, even in studies of newborn infants. With mobile devices, recordings outside laboratory settings are also feasible.
MEG is a functional neuroimaging technique, which enables us to measure the changes in magnetic fields caused by the brain’s neural activity. Magnetic currents occur naturally in the human brain, because of the synchronized activity of cortical neurons during information processing during rest and cognitive tasks. MEG has a very high temporal resolution and a fairly good spatial resolution.
In TMS, an electric current (induced by magnetic pulse) is used to stimulate neural tissue, generating action potentials on the scalp. These generated action potentials either inhibit or excite neural function. When combined with EEG, functional connections between brain areas can be investigated. TMS enables even determining causal connections between brain and behaviour.
Eye-tracking devices monitor the activity and movements of the eyes, such as pupil movements, pupil dilation, and microsaccades with millisecond accuracy. Eye-tracking allows for on-line tracking of participant's gaze direction its' changes, and can be synchronized with EEG, MEG or TMS devices.
ANS recordings allow for the on-line measurement of autonomic nervous system activity. These include, but are not limited to, heart rate, galvanic skin conductance and measurement of muscle activity, such as facial muscles whose activity is associated with emotional responses. ANS measurements can be effectively combined with EEG, MEG, and TMS recordings.
NIRSI, available in BioMag on a collaborative basis, uses near-infrared light to record changes in oxygenated and deoxygenated blood in the human brain, in a similar fashion as the blood oxygen-level dependent (BOLD) signal in the functional magnetic resonance imaging (fMRI) recordings. While the suboptimal feature of fMRI is the noise, requiring hearing protection for the participant and disrupting experiments using audio, NIRSI is fully silent. NIRSI does not use strong magnetic fields to assess the changes in the BOLD signal, allowing for use of metal objects near the device.