DESCRIPTION: The proposed experimental, simulation, and theoretical EEG studies will develop modern engineering tools for future use by cognitive and medical scientists. These tools are potentially applicable to a wide variety of disease states, including mental disorders (ADHD, depression, schizophrenia, depression, sleep disorders, etc.) and neurological conditions (epilepsies, head trauma, strokes, coma, Alzheimer's disease, etc.). The proposed tools combine high-resolution EEG with MEG and new methods to quantify dynamic (spatial-temporal) properties of EEG and steady-state visually evoked potentials (SSVEP). Experimental studies will apply high-resolution SSVEP dynamic measures to investigate conscious perception, selective attention, perceptual organization, and working memory. Methods to identify genuine measures of functional integration between cortical areas will be developed and tested with high-resolution SSVEP. SSVEP provides robust measures of neocortical dynamic and cognitive function that are largely artifact-free. SSVEP measures of the "competition" between functional localization and integration will include coherence and other phase locking measures in various frequency bands. The experimental SSVEP data will be interpreted in the context of cell assembly formation embedded within a background of "synaptic action fields" using theoretical models of neocortical dynamic function based on genuine physiology and anatomy. The synaptic action fields are defined as the number densities of active excitatory and inhibitory synapses at any time, independent of function. This theoretical construct provides the necessary connection between physiology and EEG/SSVEP data. In this manner, a triple correspondence between EEG dynamics, cognitive processes, and theoretical models will be obtained. The EEG and SSVEP tools developed in these studies should provide firm foundations for later studies applied to a wide range of specific cognitive or medical conditions. These tools will be freely distributed as software for high-resolution EEG, SSVEP, and MEG analysis with a supporting manual and examples [unreadable] [unreadable]