Grant: Research Tools and Instruments - Category 1 (<$150,000)

The brain contains billions of cells, but at any moment in time only small subsets of these cells become co-active. These subsets of cells form functional networks that co-activate only over few hundreds of milliseconds when the brain engages in focused attention towards particular stimuli in our environment. Our research equipment promises to elucidate the mechanisms that underlie the dynamic formation of these selective functional networks of cells in the brain by using recently developed fine-scale electrophysiological techniques. To understand the temporal dynamics of network formation, it is pivotal to record from many, isolated cells at the same time as animals switch from a non-selective state (e.g. none-attentive idling), to a selective state (e.g. focused attention). During this switching of states, cells exchange information and become co-active, but it has remained one of the big challenges in systems neuroscience to measure many co-active cells while animals perform higher attentional functions. The major challenges lie at three fronts: First, the small subset of cells whose activity carries relevant information need to be identified. Second, these cells need to be clearly isolated from the dense matrix of neighboring cells by using electrophysiological probes with a high signal-to-noise ratio. And thirdly, these cells need to be kept isolated for prolonged times to be able to infer network mechanisms and their functional importance for behavior in controlled attention experiments. This application proposes the use of a triade electrode drive system that surmounts these challenges with maximal efficiency. Each triade system allows to manipulate independently the depth of three high signal-to-noise electrodes. By combining several triade systems, it becomes feasible to identify, isolate and stabilize multiple single cells at the same time. The time-efficiency of the system allows to measure networks of single cells for prolonged times while subjects perform well controlled attention experiments - promising unprecedented insights into the mechanisms underlying the formation of selective functional networks.