The CNV component was first described by W. Grey Walter and colleagues in an article published in Nature in 1964.
[2] The importance of this finding was that it was one of the first studies which showed that consistent patterns of the amplitude of electric responses could be obtained from the large background noise which occurs in EEG recordings and that this activity could be related to a cognitive process such as expectancy.
In their study, Grey Walter et al. (1964) [2] presented a "warning stimulus" (e.g., a single click or flash of light) to a human subject.
They observed that: In 1990 Bozinovska et al devised a CNV-based brain-computer interface to control a computer buzzer.
[3][4] In 2009, Bozinovski and Bozinovska designed a CNV-based brain-computer interface experiment, where the CNV controlled a physical object, a robot.
Studies have shown that the CNV appears after about 30 trials of paired stimuli, although this number can be reduced when the subject understands the task in advance.
When the imperative stimulus is removed unexpectedly, the CNV attenuates until it is completely suppressed after about 20–50 trials.
Fifth, when subjects were asked to pay attention and respond quickly, CNV amplitude was increased.
Loveless and Sanford (1975) and Weerts and Lang (1973) increased the interstimulus interval to greater than 3 seconds and showed that two components can be visually distinguished from the CNV.
[10] A related, important issue has been the question of whether all or part of the CNV corresponds to the readiness potential.
Both components have a similar scalp distribution with a negative amplitude and are associated with a motor response.
For example, Hultin, Rossini, Romani, Högstedt, Tecchio, and Pizzella (1996) used magnetoencephalography (MEG) to determine the location of the electromagnetic source of the CNV wave.
Their experiment suggests that the terminal CNV is located within Brodmann's area 6 and corresponds to the premotor cortex.
[12] The work done by Zappoli and colleagues is another example of research completed to determine the generators of the CNV component.
[13] Zappoli reviews evidence which shows that in certain cases epileptic discharges affect the expectance waves and therefore decrease the CNV amplitude.
Zappoli also described research which investigated the CNV characteristics in patients which had lobotomies of frontal regions.
Walter and colleagues suggested that CNV amplitude varies directly with subjective probability or expectancy of the imperative stimuli.