Table 2.

Combinations of brain signals.

Task 1	Task 2	Sensor placement	Modalities	Activity type
Steady-state visual evoked potential (SSVEP)	P300	Occipital and parietal	Electroencephalography(EEG)	Reactive
SSVEP	Motor signals	Occipital and motor	EEG	Combination of reactive and active
Motor signals	P300	Parietal and motor	EEG	Combination of active and reactive
P300	Eye movement	Parietal, motor and eyes	EEG + electrooculography (EOG)	Reactive
Prefrontal signals	Motor signals	Prefrontal and motor	EEG + functional near infrared spectroscopy (fNIRS) (fNIRS individual in some cases)	Active for both individual fNIRS and fNIRS combined with EEG