The goal of this proposal is to install CLARITY at this James A. Haley Veterans' Hospital in Tampa, FL. CLARITY is a revolutionary new system that can see inside post-mortem tissue. Until now researchers have had to slice the tissue into thin sections and then visualize small areas of the tissue. With CLARITY the entire tissue, such as a whole brain, spinal cord, heart or other tissue, is made transparent allowing researchers to investigate the subcellular structure, neuronal network, specific proteins, biomolecular complexes and gene expression profiling at the resolution of single cells. For the first time, researchers can visualize the entire brain, spinal cord, or other tissue for defects associated with neurodegenerative diseases, traumatic brain injury, aging, cancer, cardiovascular disease and stroke. MRI and other imaging methods are good for living tissue, but they do not provide resolution at the single cell level, they cannot identify mild traumatic brain injury, nor can they identify changes that precede full-blown pathology. MRI is not applicable to small animals, such as rats and mice, the animals of choice in neuroscience research. As reviewers, we are now seeing grants from other institutions that use CLARITY in their projects. Indeed, grants that use traditional anatomical and neuroanatomy methods are being rejected. To maintain our competitive edge it is essential to install CLARITY. This equipment will accomplish the following specific aims: i) image neural circuits and molecular pathways and mechanisms activated by optogenetic stimulation, ii) identify defects in these circuits and pathways in response to alcohol and drug addiction and specific diseases, iii) identify where these pathways are disrupted in response to cardiovascular disease, renal disease, traumatic brain injury, stroke, spinal cord injury, Alzheimer?s disease and Parkinson?s disease.