Recent Advances in Neurocognitive Pattern Analysis. In: Başar E, editor. Dynamics of Sensory and Cognitive Processing by the Brain. Berlin: Springer Berlin Heidelberg; 1988. pp. 88-102. [DOI: 10.1007/978-3-642-71531-0_5]

High resolution evoked potentials of cognition

The precision of four methods of quantifying neuroelectric signals has been improved by increasing EEG spatial sampling, using up to 124 electrodes, and by accurate anatomical registration of the EEG with Magnetic Resonance Images (MRIs). One such method, equivalent dipole modeling, is a well-known form of source localization which is useful when the generator of the scalp recorded signal approximates a simple dipolar source, as is usually the case with early and mid-latency Evoked Potentials (EPs). Two methods of enhancing spatial detail which benefit from increased spatial sampling include the Laplacian Derivation and the Finite Element Deblurring method. The latter is a new technique which estimates the EP distribution at the superficial cortical surface. The fourth method, Evoked Potential Covariance, characterizes the spatiotemporal relationships among EP segments at different recording sites. This is useful when studying "functional neural networks" underlying higher cognitive functions. These methods are reviewed and examples of results of their application in recent experiments are presented.

Beyond topographic mapping: towards functional-anatomical imaging with 124-channel EEGs and 3-D MRIs

A functional-anatomical brain scanner that has a temporal resolution of less than a hundred milliseconds is needed to measure the neural substrate of higher cognitive functions in healthy people and neurological and psychiatric patients. Electrophysiological techniques have the requisite temporal resolution but their potential spatial resolution has been not realized. Here we briefly review progress in increasing the spatial detail of scalp-recorded EEGs and in registering this functional information with anatomical models of a person's brain. We describe methods and systems for 124-channel EEGs and magnetic resonance image (MRI) modeling, and present first results of the integration of equivalent-dipole EEG models of somatosensory stimulation with 3-D MRI brain models.

Dynamic functional topography of cognitive tasks

Improved neuroelectric recording and analysis tools are yielding increasingly specific information about the spatial and temporal features of neurocognitive processes. Such tools include recordings with up to 125 channels, digital signal processing techniques, and correlation of neuroelectric measures with anatomical information from magnetic resonance images. These tools, and their application to the study of cognitive functions, are presented in this paper.