contingent negative variation
A type of event-related potential, believed to indicate attention, consisting of a large negative change in potential voltage across the cerebral cortex, especially in the frontal lobe, that develops slowly in a person who is actively expecting the occurrence of some significant stimulus requiring a response. It is observable as an evoked potential occurring typically during the 1–2 seconds after a warning signal is given. See also P300. Compare readiness potential. CNV abbrev.