Several neuropsychiatric disorders are characterized by avoidance behaviors. For instance, people with major depressive disorder may avoid engaging in social interactions or partaking in tasks and experiences to avoid unpleasant emotions. Despite this, the neurobiological underpinnings of avoidance behaviors remain unclear. To address this, our lab and others have employed a lever-press avoidance task wherein rats press a lever to avoid footshock. Previous research using this task demonstrates that antagonism of dopamine receptors or cannabinoid type-1 receptors attenuates avoidance behavior when rats are learning the task, but manipulations to these systems has no effect on behavior once avoidance is well-learned. To determine which brain regions may play a role in learning versus maintaining well-learned avoidance behavior we will combine avoidance behavior with immunohistochemical analysis for the protein product of the immediate early gene c-fos. Animals are trained on the avoidance task until they reach about 50% avoidance behavior (still learning) or greater than 80% avoidance behavior (well-learned avoidance). An hour after their final behavioral session, rats are euthanized and their brains are flash frozen. Brains are then sliced into coronal sections, mounted on slides and stained for the c-fos protein using immunohistochemistry. Stained slides are viewed under the microscope and c-fos expression is quantified in eight key mesolimbic and cortical brain structures using a microscope running custom software. Differences in c-fos expression serve as a proxy for cellular activation. Our data will thus elucidate differential involvement of key brain structures in learning avoidance behavior versus maintaining well-learned avoidance.

The brain is excellent at delegating tasks, giving each region within it a different goal and the capabilities to do it. Is this differentiation solely made because different areas lack the connections to parts of the body that others have, or is it because of something else? Using a brain-machine interface (BMI), we can investigate this phenomenon by providing areas of the brain with minimal direct involvement in motor function the ability to do so. During normal brain function, neurons in the M1 region of the brain give direct commands to the muscles to perform specific movements. However, the M1 region of the brain receives input from the premotor cortex (PMd) and is critical for motor planning. Connecting the PMd region and the M1 region directly into a BMI control task can reveal the underlying behaviors of the two regions when given similar functions. By training non-human primates to perform tasks using a BMI connected to those two areas, we investigate how the two regions’ neurons interact with their local environment through evaluation of spike-field coherence.