Graded Changes in Evoked Response (P300) Amplitude as a Function of Cognitive Activity

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Graded function, Cortical processor

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Using a stepwise discriminant analysis, we demonstrate that the amplitude of P300 is a graded function of the complexity of information processing required of a S following a stimulus. This relationship between cognitive complexity and P300 is apparent only when the S is not pressed to generate fast and accurate discriminant responses to the stimuli. Under a reaction-time regime, a large P300 is elicited independently of stimulus predictability or cognitive complexity. It seems that P300 is a measure of the amount of activity of a general-purpose cortical processor.

Citation / Publisher Attribution

Perception & psychophysics, v. 14, issue 2, p. 319-324