132:
was reduced. Second, in one condition subjects were allowed to choose whether they were going to press the button or not. In trials where the subject chose not to respond, there was no CNV. Third, when the subject was specifically told that there would not be repetitive flashes, no CNV was elicited. Fourth, another condition showed that a CNV was elicited in subjects who were told to estimate when the repetitive flashes would come even when no flashes were presented. Fifth, when subjects were asked to pay attention and respond quickly, CNV amplitude was increased. The results of these conditions suggest that the CNV is related to attention and expectancy.
190:. This was the general consensus until other work provided evidence that the CNV can be distinguished from the RP. First, the RP is usually lateralized to the contralateral side of the motoric response, while the CNV is usually bilateral. Second, the CNV can occur even when a motor response is not required. Third, a RP occurs without any external stimuli. This shows that the RP occurs for motor responses while the CNV occurs when two stimuli are contingent with each other.
85:
indistinguishable from noise. On the other hand, when a single click is followed by the repetitive flashes which are terminated by a button press, there is a large gradual negative peak which ends sharply with the button press. This is the contingent negative variation. Another classical study was described by Joseph Tecce in the
Psychological Bulletin in 1972. In this review, Tecce summarizes the development, morphology, and locus of appearance of the CNV.
50:
subject simply experienced warning and imperative stimuli passively; in others, the subject could prevent the imperative stimulus, if it occurred, by a behavioral response, e.g., pressing a button, but the button worked only if it was pressed after the imperative stimulus had occurred (i.e., premature button presses were ineffective). The process of warning stimulus optionally followed by imperative stimulus recurred at variable intervals between 3–10 sec.
54:
varied with the time gap between the warning and imperative stimuli (and whether the imperative stimulus occurred) and the subject's attention/vigilance. Walter et al labeled the sustained component the "contingent negative variation" because the variation of the negative wave was contingent on the statistical relationship between the warning and imperative stimuli. They observed that:
94:
a clear CNV. This response could be a physical or mental response. The CNV is elicited when two, linked stimuli are presented. When the imperative stimulus is removed unexpectedly, the CNV attenuates until it is completely suppressed after about 20–50 trials. The CNV is immediately restored if paired with the imperative stimulus again.
149:
subject must pay more attention to perceive the low-intensity stimulus. If the detection of the imperative task becomes too difficult, then the CNV amplitude is reduced. In other words, attention to the imperative stimulus is important for the development of the CNV and increased task difficulties distract the attention.
186:. The readiness potential is the neural preparation for motoric responses. Both components have a similar scalp distribution with a negative amplitude and are associated with a motor response. In fact, many researchers claimed that the terminal CNV, or E wave, was in fact the readiness potential, or
223:
Many theories have been posited to account for cognitive processes underlying the CNV component. Walter and colleagues suggested that CNV amplitude varies directly with subjective probability or expectancy of the imperative stimuli. Other researchers suggested that the CNV amplitude varies with the
209:
The work done by
Zappoli and colleagues is another example of research completed to determine the generators of the CNV component. Zappoli (2003) studied the ERP patterns, including the CNV, of subjects with brain disorders or brain damage. Zappoli reviews evidence which shows that in certain cases
173:
Most researchers agree that the CNV component has been associated with information processing and response preparation. The main controversy is whether the CNV is composed of more than one component. After discovery of the CNV, researchers were able to distinguish between two main components of the
131:
also affects the amplitude of the CNV. The following examples from various task conditions and studies show that the CNV is changed when the experimental protocol changes the attention needed to perform the tasks. First, when subjects were told that the imperative stimulus would be removed, the CNV
398:
L. Bozinovska, G. Stojanov, M. Sestakov, S. Bozinovski. CNV pattern recognition – a step toward cognitive wave observation. In: L. Torres, E. Masgrau, M. Lagunas, editors. Signal processing: theories and applications. Proceedings of the Fifth
European Signal Processing Conference (EUSIPCO 90); 1990,
178:
wave. This wave showed enhanced amplitude in the frontal regions. The second wave preceded the imperative stimulus and was called the E wave, or expectancy wave. A study conducted by
Gaillard (1976) provided further evidence that the O wave was frontally distributed and was more strongly affected
102:
The negative CNV peak rises around 260–470 ms after the warning stimulus. It will rise quickly if the subject is uncertain about when the imperative stimulus will be, and it will rise gradually if the subject is confident about when the imperative stimulus will be. The maximum amplitude is usually
93:
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. Light flashes, clicks, and tones have all been used to elicit the CNV. A response to the imperative stimulus is necessary to elicit
49:
In their study, Grey Walter et al. (1964) presented a "warning stimulus" (e.g., a single click or flash of light) to a human subject. The warning stimulus was randomly followed (or not followed) by an "imperative stimulus" (repetitive clicks or flashes) 0.5-1 second later. In some situations, the
36:
and colleagues in an article published in Nature in 1964. 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
53:
The experimenters found that EEG responses to the warning stimulus seemed to have three phases: a brief positive component, a brief negative component, and a sustained negative component. The brief components varied with sensory modality (e.g., visual vs auditory), while the sustained component
148:
Some researchers have shown that the intensity of the stimulus may affect the CNV amplitude. It seems that the CNV component has a higher amplitude for stimuli that have low-intensity, i.e. is difficult to see or hear, as opposed to stimuli that have high-intensity. This could be because the
84:
Walter et al. (1964) showed that a single click elicits a brief positive peak and a brief negative peak. Repetitive flashes elicit brief positive and negative peaks. If these stimuli are separated by 1 sec the same individual patterns result. After around 50 presentations, these peaks are
165:(ISI). The most frequent ISI used is between 1.0–1.5 seconds. Trials with an ISI between 0.5–1.5 elicit a robust CNV wave. When the ISI is reduced to 0.125 or 0.25 seconds, the CNV becomes suppressed. On the other hand, trials with an ISI of 4.8 seconds show reduced CNV amplitude.
152:
In related studies, researchers have also shown that the larger the motoric response needed, the larger the CNV. Studies with subjects that have a lack of sleep tend to show a reduced CNV. This provides further evidence that lack of attention might decrease the CNV amplitude.
174:
CNV. 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. The first wave followed the warning stimulus and was called the O wave, or
214:
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. The CNV amplitudes were decreased or absent in these patients.
119:
There is much research which describes what stimulus characteristics can affect characteristics of the CNV. For example, intensity, modality, duration, stimulus rate, probability, stimulus relevance, and pitch discrimination can affect the CNV component.
417:
A. Bozinovski, L. Bozinovska. Anticipatory Brain
Potentials in a Brain-Robot Interface Paradigm. Proceedings of the 4th International IEEE EMBS Conference on Neural Engineering, Antalya, Turkey, p. 451-454, 2009
349:
Hilmar
Gudziol, Orlando Guntinas-Lichius. Chapter 16 - Electrophysiologic assessment of olfactory and gustatory function. In: Handbook of Clinical Neurology, Volume 164, 2019, Pages 247-262. Elsevier.
224:
intention to perform an act. Another theory is that CNV varies with the motivation of the subject to complete the task. Tecce suggests that the CNV is related to both attention and arousal level.
364:
Walter, W.G; Cooper, R.; Aldridge, V.J.; McCallum, W.C.; Winter, A.L. (1964). "Contingent
Negative Variation: an electric sign of sensorimotor association and expectancy in the human brain".
408:
L Bozinovska, S. Bozinovski, G. Stojanov. Electroexpectogram: experimental design and algorithms. Proceedings of the IEEE International. Biomedical. Engineering Days; 1992. Istanbul. p. 58–60
202:(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
198:
Another important topic in studying the CNV component is localizing the general source of the CNV. For example, Hultin, Rossini, Romani, Högstedt, Tecchio, and
Pizzella (1996) used
140:
When the probability of repetitive flashes is random and the repetitive flashes are removed in about 50% of the trials, the amplitude of the CNV is about half as that of normal.
654:
Hultin, L.; Rossini, P.; Romani, G. L.; Högstedt, P.; Tecchio, F.; Pizzella, V. (1996). "Neuromagnetic localization of the late component of the contingent negative variation".
76:
to control a computer buzzer. In 2009, Bozinovski and
Bozinovska designed a CNV-based brain-computer interface experiment, where the CNV controlled a physical object, a robot.
726:
673:
Zappoli, R. (2003). "Permanent or transitory effects on neurocognitive components of the CNV complex induced by brain dysfunctions, lesions, and ablations in humans".
479:
Frost, B.G.; Neill, R.A.; Fenelon, B. (1988). "The determinants of the non-motoric CNV in a complex, variable foreperiod, information processing paradigm".
749:
514:
Loveless, N.E; Sanford, A.J. (1975). "The impact of warning signal intensity on reaction time and components of the contingent negative variation".
549:
Weerts, T.C.; Lang, P.J. (1973). "The effects of eye fixation and stimulus and response location on the contingent negative variation (CNV)".
28:(EEG), that occurs during the period between a warning stimulus or signal and an imperative ("go") stimulus. The CNV was one of the first
980:
719:
774:
1001:
712:
264:
800:
769:
324:
249:
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amplitude was more prominent in situations where the subject could exert control by preventing the imperative stimulus.
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965:
850:
254:
244:
239:
73:
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Ruchkin, D.S.; Sutton, S.; Mahaffey, D.; Glaser, J. (1986). "Terminal CNV in the absence of motor response".
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754:
259:
29:
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234:
199:
187:
162:
25:
584:
Gaillard, AW (1976). "Effects of warning-signal modality on the contingent negative variation (CNV)".
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A related, important issue has been the question of whether all or part of the CNV corresponds to the
759:
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Tecce, J.J. (1972). "Contingent negative variation (CNV) and psychological processes in man".
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38:
970:
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33:
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924:
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the amplitude returned when the imperative stimulus followed the warning stimulus;
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when the warning stimulus was repeated without a subsequent imperative stimulus;
59:
704:
111:
The CNV appears most prominently at the vertex and is bilaterally symmetrical.
919:
914:
904:
929:
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329:
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32:(ERP) components to be described. The CNV component was first described by
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385:
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944:
975:
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The amplitude of the CNV changes when one changes the foreperiod, or
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Barcelona. 1990, Elsevier Science Publishers; 1990. p. 1659–1662
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the amplitude of the EEG response became attenuated, or
24:) is a negative slow surface potential, as measured by
953:
895:
783:
742:
656:
Electroencephalography and Clinical Neurophysiology
621:
Electroencephalography and Clinical Neurophysiology
750:Amplitude integrated electroencephalography (aEEG)
179:by auditory stimuli rather than visual stimuli.
720:
72:In 1990 Bozinovska et al devised a CNV-based
8:
359:
357:
355:
981:Neurophysiological Biomarker Toolbox (NBT)
727:
713:
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675:International Journal of Psychophysiology
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472:
436:
434:
432:
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428:
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342:
7:
37:this activity could be related to a
836:Contingent negative variation (CNV)
775:Brainstem auditory evoked potential
14:
265:Lateralized readiness potential
770:Somatosensory evoked potential
325:Somatosensory evoked potential
250:Early left anterior negativity
1:
966:Difference due to memory (Dm)
687:10.1016/S0167-8760(03)00054-0
18:contingent negative variation
765:Magnetoencephalography (MEG)
736:Electroencephalography (EEG)
633:10.1016/0013-4694(86)90127-6
598:10.1016/0301-0511(76)90013-2
563:10.1016/0301-0511(73)90010-0
528:10.1016/0301-0511(75)90021-6
493:10.1016/0301-0511(88)90002-6
760:Electrocorticography (ECoG)
1023:
80:Component characteristics
255:Error-related negativity
245:Difference due to memory
124:Attention and expectancy
74:brain-computer interface
887:Late positive component
755:Event-related potential
260:Late positive component
30:event-related potential
1002:Electroencephalography
796:Bereitschaftspotential
443:Psychological Bulletin
235:Bereitschaftspotential
200:magnetoencephalography
188:Bereitschaftspotential
163:interstimulus interval
157:Interstimulus interval
115:Functional sensitivity
103:around 20 microvolts.
26:electroencephalography
586:Biological Psychology
551:Biological Psychology
516:Biological Psychology
481:Biological Psychology
41:such as expectancy.
940:Sensorimotor rhythm
897:Neural oscillations
841:Mismatch negativity
315:P300 (neuroscience)
270:Mismatch negativity
184:readiness potential
1007:Evoked potentials
989:
988:
883:(late positivity)
785:Evoked potentials
372:(4943): 380–384.
169:O-wave and E-wave
39:cognitive process
1014:
971:Oddball paradigm
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204:premotor cortex
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681:(2): 189–220.
665:
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627:(5): 445–463.
611:
592:(2): 139–154.
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541:
522:(3): 217–226.
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45:Main paradigms
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34:W. Grey Walter
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743:Related tests
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449:(2): 73–108.
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961:10-20 system
925:Theta rhythm
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194:Localization
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92:
83:
71:
52:
48:
21:
17:
15:
851:C1 & P1
557:(1): 1–19.
487:(1): 1–21.
136:Probability
89:Development
996:Categories
920:Delta wave
915:Gamma wave
905:Alpha wave
847:Positivity
792:Negativity
662:: 425–448.
337:References
107:Topography
98:Morphology
60:habituated
930:K-complex
910:Beta wave
811:Visual N1
330:Visual N1
240:C1 and P1
212:epileptic
176:orienting
144:Intensity
129:Attention
695:12763574
386:14197376
228:See also
945:Mu wave
641:2420561
606:1276304
571:4804295
536:1139019
501:3251557
463:4621420
976:EEGLAB
954:Topics
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366:Nature
219:Theory
881:P600
866:P300
861:P200
831:N400
826:N2pc
821:N200
816:N170
806:N100
801:ELAN
691:PMID
637:PMID
602:PMID
567:PMID
532:PMID
497:PMID
459:PMID
382:PMID
320:P600
310:P200
295:N400
290:N200
285:N170
280:N100
275:N2pc
16:The
876:P3b
871:P3a
856:P50
683:doi
629:doi
594:doi
559:doi
524:doi
489:doi
451:doi
374:doi
370:203
305:P3b
300:P3a
22:CNV
998::
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728:e
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714:v
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20:(
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