Learning, memory and cognition
Studies of spontaneous (EEG) and induced (ERPs) brain electrical activity related to learning and memory during acquisition and performance of learned behaviors. These studies examined mechanisms of information processing:
a) in behaving animals at the level of the firing patterns of single neurons and cell ensembles, with moving microelectrodes and with arrays of chronically implanted large electrodes sampling many cortical and subcortical brain regions; and
b) in human subjects at rest and during performance of cognitive tasks quantifying rhythmic electrical oscillations both in the spontaneous electroencephalogram (EEG) and event related potentials (ERP), using arrays of scalp electrodes to record the electrical activity.
Evidence was rapidly forthcoming of striking similarities among certain aspects of brain electrical activity in both animals and human subjects. In particular, it soon became evident that during decision making tasks, brain electrical activity was comprised of two separate streams. One stream (exogenous) reflected encoding of incoming information and its dispersion among many brain structures, best seen in sensory specific and association regions; a second stream (endogenous) consisted of patterns of neural activity, especially in non-specific brain regions, released automatically from memory stores due to its salient relevance to the current inputs. A comparator of the similarity between the exogenous and endogenous streams determined subsequent behavior. These findings led to a still ongoing series of experiments to develop a theory of brain processes related to consciousness and cognition.