Evoked activity (or responses)

Recording of massed activity of the brain to any kind of stimulation in any particular modality.  The responses are phase-locked to the stimulus onset (in contrast to stimuli associated with the amplitude of oscillatory activity, and referred to as ‘induced activity’.  Large populations of intracranial neurons generate electrical fields (viz., fled potentials) that spread to the scalp by means of volume conduction.  Many deep subcortical structures (e.g., thalamus) cannot be accessed by the distant mass recordings of EEGs.       

See Brain (or neuro-) imaging, Electroencephalogram (EEG), Event-related (brain) potentials (ERPs), Thalamus