Spatial and Temporal Properties of the Slow Components of the Contingent Magnetic Variation in a Warned Choice Reaction Time Task
Electrically recorded contingent negative variation, eCNV, has been reported as a two-component wave . The early component, the O-wave (orientation-wave), is related to the processing of the warning stimulus (S1) and is sensitive to information that S1 provides with respect to the imperative stimuli (S2). The late component, the E-wave (expectation-wave), is considered to be a manifestation of at least two major processes: motor preparation and stimulus anticipation. The electrical O-wave has a frontocentral distribution, with right hemisphere preponderance, while the E-wave is located precentrally, with a preponderance contralateral to the side of the movement. The CNV is a cognitive process where the neurological responses are constantly changing during an experimental session, due to alterations in the state of alertness of the subject, the process of learning and the reorganization of mental strategy to perform the task. During an initial learning period the amplitudes of the eCNV are decreasing and the potential distribution changes. Recordings of Contingent Magnetic Variation (CMV), the neuromagnetic counterpart of the eCNV, have been reported by several authors [e.g. 2, 3]. The scope of this study was to analyze the presence, distribution, and origin of slow components of CMV in a warned choice reaction time task after the initial learning period has been performed.
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