A long-latency comnponent of the averaged evoked potential recorded from the human scalp varied in close relationship with subjects' perceptual reports in an auditory signal detection task. Detected signals evoked potentials several times larger than did undetected signals, falsely reported signals, or correctly reported nonsignals. The threshold signal intensity at which detection perfornmance exceeded chance levels was identical with concurrently obtained electro-physiological measures of threshold.

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Vertex potentials were recorded from eight Ss performing in an auditory threshold detection task with rating scale responses. The amplitudes and latencies of both the N 1 and the late positive (P3) components were found to vary systematically with the criterion level of the decision. These changes in the waveshape of the N 1 component were comparable to those produced by varying the signal intensity in a passive condition, but the late positive component in the active task was not similarly related to the passively evoked P2 component It was suggested that the Nl and P3 components represent distinctive aspects of the decision process, with N 1 signifying the quantity of signal information received and P3 reflecting the certainty of the decision based upon that information.

Two experiments were conducted to determine whether hyperactive boys have a unique deficit in sustained attention. Groups with DSM-III diagnoses of attention deficit disorder (ADDH), conduct disorder (CD), ADDH + CD, and learning disorder were compared with normal controls on the

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Until recently, most psychophysical experiments have studied sensory mechanisms involved in processing signals that vary along a single dimension. Under ordinary circumstances, however, the sensory system must operate in an environment where incoming signals vary along many different dimensions and often must deal with signals occurring simultaneously in different sensory modalities. In this report, we explore the question of how an O's performance on a set of simple discrimination tasks is affected by requiring the 0 to perform a number of these tasks at the same time.

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