The neural pathways underlying sensory perception are richly structured systems, with multilayered recurrent connections between cell types within a cortical layer, between cortical laminae, between areas within a sensory pathway, and between different brain regions. Despite substantial progress characterizing neural responses, it is particularly challenging to determine causal interactions within recurrently connected circuits due to the confounding influence of the interconnections. Drs. Rozell and Stanley plan to design a closed-loop stimulation system to decouple recurrently connected elements and clamp neural ensemble activity. Notably, the system will work in real-time by analyzing neural activity and feedback to guide stimulation on a scale of milliseconds. The team proposes to test this system in the rodent whisker barrel cortex – though applications in other brain areas, as well as the development of new medical devise based on the controller architecture, could likely result.