The odd-ball paradigm is used in neuroscience to see if a subject is able to distinguish and recognize a stimulus. The subject is presented with sequences of two stimuli, which differ by physical characteristics. One of the stimuli needs frequent, the other rarely (the latter is the target stimulus), the subject must recognize and count the rare stimuli. The generation of the P300 is considered to be an expression of a cognitive process of discrimination and categorization of stimuli.
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