This proposal utilizes a brand new technology called optogenetic fMRI (ofMRI)(pioneered by Dr. Lee) combined with advanced imaging, computation, and applied mathematical algorithms. Optogenetics, is a genetic technology that allows neural circuit elements to be triggered selectively based on their genetic identity with temporal precision, while passband b-SSFP fMRI, provides high quality functional brain activation maps to be obtained of MRI is a technology that combines the two to visualize precise causal response of the brain circuit upon selective triggering. This allows the brain circuit element's causal role in the system level outcome to be evaluated. However, in order to parse through the massive combination of the brain circuit's response, real-time interactive monitoring is necessary while the small, dense structures of the brain requires high resolution acquisition. The PI aims to design and implement novel parallel computation and compressed sensing (CS) reconstruction algorithms to achieve these goals. The implementation will then be utilized to look at brain circuit responses to a range of frequency stimulation. In particular, the motor cortex (M1), striatum, thalamus, and substantia nigra (Stn) will be stimulated in order to precisely map the system known to be correlated with the motor symptoms of Parkinson's disease. Brain activity amplitude, shape, and distribution will then be carefully compared to analyze the circuitry.