The brain is no longer considered a “black box” because new devices and genetically- engineered biosensors have made it possible to monitor activity of cells deep in the brain. However, the brain is comprised of many different types of cells, and a device is needed that monitors activity of different types of cells adjacent to each other especially in animals actively engaged in behavior. Over the last year a new breakthrough technology was made available - a miniature microscope that weighs only 2g, makes it possible to monitor activity of two different cells in freely-behaving rodents. This device identifies activity patterns of brain cells during specific behaviors, allowing investigators to construct brain activity maps of specific brain circuits regulating purposeful behavior. Researchers can determine how neurodegenerative disease or specific conditions such as traumatic brain injury or substance abuse affects circuit function. The nVue miniscope system enables investigators to identify activity at the single cell level and how dysfunctional activity at the local level can cause pathological behavior. However, the necessary core instrumentation that would serve to measure critical indices of cell signaling, quantification and imaging, are not currently available to an individual investigator at RHJ VAMC. The instrumentation requested in this proposal will directly address this issue. The underlying hypothesis of this proposal is that abnormal cell signaling in specific brain circuits leads to pathological behavior. A device is needed to monitor activity of brain circuits. This equipment will accomplish the following specific aims: i) image brain circuits activated during purposeful behavior, and ii) identify change in circuit activity in response to disease, substance abuse, and traumatic stress or brain injury. By mapping activity in local circuits it will be possible to reestablish activity and restore normal behavior.