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Cognitive and Neural Bases of Skilled Performance

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Annual technical rept. 1 Oct 1987-30 Sep 1988

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The results obtained using an odd-ball paradigm were inconclusive, but a new procedure was developed which uses all trials rather than trials on which only infrequent events lead to P300 responses. It is tentatively concluded that different source configurations underly P300s associated with different modalities, and possibly also different tasks within a modality. In the previous report we described a new method for analyzing spontaneous brain activity in the alpha bandwidth. We extended this method to other bandwidths and conducted some of the first studies of the modulation of spontaneous brain activity, independent of the evoked response, during the performance of high-level cognitive tasks. Research based on this methodology is now being conducted under the aegis of a separate grant. In the course of this report period we conducted a study using the 14-channel neuromagnetometer at Bellevue Hospital. The left hemisphere tends to display a monotonic increase in N100 amplitude with ISIs up to 16 sec, while the right hemisphere is not differently affected by ISIs in excess of 4 sec. In a collaborative effort with the Los Alamos National Laboratory we found that different components of auditory evoked responses originate at different locations in the two hemispheres. Also, in a study of visual responses to equiluminance color stimuli we found the first evidence for separate sources for the cardinal directions in color space. In a study of visual spatial attention we found enhanced responses to stimuli located at positions on which attention was focused. Keywords Electroencephalography, Neuromagnetism.

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  • Psychology
  • Anatomy and Physiology

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