A<unk>  is a<unk><unk>  that has a distinctive property (e.g., frequency or phase). The stimuli are simultaneously presented to the user when focusing attention on the corresponding<unk> . For example, when the user focuses attention on a<unk> , a steady state<unk> ly evoked potential is elicited which manifests as oscillatory components in the user's electroencephalogram, especially in the signals from the primary<unk>  cortex, matching the frequency or harmonics of that<unk> .<unk><unk>  stimuli are said to evoke a lesser response in brain cells, specifically superior collicular cells, than moving stimuli. Habituation is very rapid in healthy subjects in reference to<unk><unk>  stimuli. Development changes around the first year of life are attributed for attention control and these are said to be fully functional around the ages of two and four years old. This is the age that toddlers seem to now prefer moving and changing stimuli, much like healthy adults. In infants, there is evidence that supports the hypothesis that infants prefer<unk><unk>  stimuli or patterns, in comparison to moving or changing targets.
Repetitive visual stimulus
Auditory masking
Audio-visual entrainment
Noxious stimulus
Ophthalmic drug administration
Intermittent photic stimulation
Neurostimulation
Fungal contamination of contact lenses