Over the past 50 years a tremendous amount has been learned about how neurons in different parts of the brain respond to incoming sensory signals and send out commands to move our bodies. Despite these achievements, we are far from a complete understanding of brain function and alleviation of most brain disorders. A fundamental challenge that must be addressed is the need to study the system simultaneously at more than one scale. On the one hand, it is essential that processing by single neurons be understood. Yet it is also critical to elucidate the ways in which information is distributed across neurons and brain areas and integrated to give rise to unitary percepts and motor acts. Microelectrode recordings of individual neurons are highly """"""""local"""""""";it is difficult to extrapolate from single cell recordings to interacting populations. On the other hand, whole brain imaging techniques such as functional magnetic resonance imaging (fMRI) sacrifice both spatial and temporal resolution to achieve their global view. While such methods have helped reveal patterns of brain activity associated with various perceptual or motor states, the loss in spatial resolution (millimeters vs. microns) and temporal resolution (seconds vs. milliseconds), while good for human brain imaging, make direct examination of neural circuits by these more global techniques extremely difficult. This application seeks funding to obtain a state-of-the-art recording system that will bridge the local-global gap. The device gives the capability to record simultaneously from hundreds of individual neurons. At the same time, because there are two synchronized recording subsystems, it is possible to examine brain activity and interactions between populations of neurons in any two areas of the brain. The neural activity to be studied by the major users is patterns spread across individual visual and motor areas of cerebral cortex, patterns between two visual or two motor areas, and patterns between a visual area and a motor area. The experiments will be conducted using non-human primates trained to perform visual and/or motor tasks. Two microelectrode arrays, each holding 100 electrodes will be implanted in brain regions of particular interest. Recordings will be made while animals perform trained tasks. The data will reveal single-cell spiking and LFP relationships with perception and behavior, temporal relationships between active neurons, and the relationships between areas within and between the visual and motor systems. These studies, made possible by the shared instrument, will lead to major advances in our understanding of visual perception, motor coding, and visuo-motor integration for behavior. It is this type of information that is critical if one is to alleviate brain disorders associated with trauma or disease.
