Major Goals The main goal of the project is to study the dynamics of the coupling between the vascular network and neural circuits in the brain. We intend to learn details of this dynamics and use this coupling to map neural activity by recording from vascular network. Blood flow in the brain is well regulated via cell signaling pathways. Since neurons are among the most active cells in the brain, stimulation of neuron almost always leads to some level of increase in the regional blood flow. Nonetheless, since the network of vessels is a complex system, blood flow increase in one area can temporarily lead to reduction of flow in another region. We proposed to develop new brain interface platforms and conduct experiments to study subtle features of this complex dynamics and use it to map neural activity. In the first phase of the project, we built our optoelectronic brain interface platform in which advanced technologies including ECoG recording, Optogenetic stimulation, Fluorescence microscopy, and Spectral domain optical coherence tomography where combined in one experimental platform. The system allows us to selectively stimulate neuron via optogenetics, record neural activity via ECoG electrophysiology or fluorescence imaging, and measure the vascular response via coherence tomography. In phase two that we finished last year, we used all the collected data from our experiments, to study details of neuro vascular coupling and develop the mathematical models. In the next phase, we intend to use our setup and the developed model to see how accurately we can predict neural activity by only looking at the dynamics of the vessels and capillaries.