In order to understand the injured brain, it is necessary to understand the functioning of the brain as a whole. Many neurological disorders can be understood as the breakdown of the normal flow of information along the pathways in the brain. Brain injuries, such as head trauma, stroke and degenerative diseases such as Alzheimer's, disconnect these pathways leading to impaired brain function. Understanding the mechanisms which link separate brain areas to produce their integrated functions is as necessary as understanding the specific process by which the damage occurs. The long range goal of our research is to provide a basic understanding of how brain regions communicate. This goal has the potential for translation into targeted therapeutic approaches to problems of abnormal brain function.

One way for two brain regions to communicate is through a precisely paced choreography of brain cell activity in the two regions, much like a tango. Alternatively, the average level of activity in the two brain regions may be enough, just as the overall amount of arm, leg, and torso gyrations is enough to convey excitement at a dance party. Our research investigates both modes of information exchange (the two temporal codes) by recording simultaneously the activity of brain cells in two brain regions while a visual task is being performed. Single and multiunit electrophysiological recordings are made simultaneously in two cortical regions (V1/V4, V1/IT and V4/IT). Spike trains and local field potentials recorded in the two visual areas are analyzed for crosscorrelation structure. This analysis can reveal different modes of temporal processing such as oscillations or synchronized bursting. Our goal is to determine if precise patterns of activity predominate more for visual recognition or for visual attention, and the role played by average levels of activity in mediating the brain's information superhighway.