P300 and contingent negative variation in migraine

Abstract

The event-related potential (ERP) component P300 is considered a cognitive neuroelectrical indicator of central nervous system activity [1] involved with the processing of new information when attention is engaged to update memory representations [2]. P300 latency can be regarded as a measure of the relative timing of the stimulus evaluation process, indicating an upper limit on categorization and stimulus evaluation time [3], or the time taken to allocate resources and engage memory updating [4]. P300 amplitude is held to index attentional resource allocation when memory updating is engaged [2]. The P300 component in many event-related brain potential (ERP) studies is obtained using the so-called odd-ball paradigm, in which two stimuli are presented in random order, with one occurring more frequently than the other [5]. The subject is required to discriminate the infrequent or rare stimulus ("target stimulus") from the frequent or standard stimulus ("nontarget") by noting the occurrence of the target -typically by pressing a button or mental counting [6, 7]. A modification of the oddball paradigm has been developed in which infrequent-nontarget stimuli are inserted into the sequence of target and standard stimuli. When "novel" stimuli (e.g., dog barks, color forms, etc.) are presented as the infrequent nontargets in the series of more "typical" targets and standard stimuli (e.g., tones, letters of the alphabet, etc.), a P300 component that is large over the frontal/central areas is produced. This component has been dubbed the "P3a," whereas the infrequent-target stimulus elicits a parietal maximum P300 or "P3b" [8, 9]. Because this novel P300 exhibits an anterior/central scalp distribution, short peak latency, and rapid habituation, it has been interpreted as reflecting frontal lobe function Abstract We reviewed P300 and contingent negative variation (CNV) studies performed in migraine in order to identify their relevance in migraine and the role of neurophysiology in migraine. Publications available to us were completed by a Medline search. There is experimental and clinical evidence for loss of cognitive habituation in migraine which may serve as a specific diagnostic tool; therefore, we reviewed studies on migraine that analyzed habituation and lack of habituation by P300 and CNV, performing short-term habituation (STH) and long-term habituation (LTH). Finally, we described the two components of P300 (a and b) and of CNV (early and late wave) and the two abnormalities reported from the majority of studies on event-related potential in migraine: increased amplitude of average event-related potential and lack of habituation. These abnormalities are especially related to the early component characterizing orienting activity.