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Cognitive and Neural Bases of Skilled Performance.

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Annual technical rept. Sep 86-Sep 87,

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Research in seven interrelated areas has been carried out during this first year. A major advance in the capability of neuromagnetic monitoring of higher levels of brain function was achieved with the installation of a large magnetically shielded room for the sensing system. This together with a computer-controlled adaptive filter dramatically improved sensitivity to slowly-varying brain signals. A new analysis technique based on a multidimensional signal space has also been developed to characterize the neural configurations that give rise to differing field patterns, without restricting consideration to only the simplest that can be attributed to an equivalent current dipole. Successful application of these concepts to studies of the alpha rhythm also demonstrated a major advantage in using elements of the covariance matrix across sensors to reduce interference from extraneous neural sources, thereby improving the signal-to-noise ratio by an order of magnitude. In preparing for a series of collaborative studies, various methods for producing visual displays in the shielded room were evaluated, and one based on a single-lens TV projection system was chosen. The system can be controlled by a computer peripheral to the HP9000550 used to record and analyze neuromagnetic data. Software was successfully developed so that either an IBMPC-compatible or Amega computer can be used for this purpose. An Adage 3000 frame buffer was obtained for psychophysical studies, and programs were developed to present a display where only color or only luminance changes are produced.

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  • Psychology

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