Contingent Negative Variation (CNV) refers to an electrical brain potential displayed as a negative deflection that occurs between two events or stimuli in a cognitive task. It is a measure of the brain's anticipatory processes and is indicative of the motivational and attentional aspects of cognitive processing.
The CNV is typically observed in electroencephalogram (EEG) recordings and is characterized by a slow, negative shift in voltage that occurs between a warning stimulus (S1) and a subsequent imperative stimulus (S2). It reflects the brain's preparation and expectation for the impending stimulus or response.
The CNV waveform has two major components: an initial negative deflection known as the 'early CNV' and a prolonged, sustained negative deflection called the 'late CNV.' The early CNV is thought to represent the preparatory processes associated with the allocation of attention, while the late CNV is believed to reflect the active maintenance of an expectancy state and the temporal integration of information to produce an appropriate response.
The CNV has been extensively studied in cognitive and neurophysiological research, particularly in the areas of attention, memory, decision-making, and motor preparation. It has been found to be sensitive to factors such as stimulus probability, task relevance, and environmental context, and has been used as a neural marker of processes like expectancy, timing, and response anticipation.
Overall, contingent negative variation provides valuable insights into the cognitive processes underlying attentional allocation, motivation, and response preparation, making it a valuable tool in the study of human brain function.
