Optimized Stereotactic Injection Protocol for Targeting the Locus Coeruleus with Minimal Neurotoxicity

The Locus Coeruleus is a critical brain region known for its vulnerability to mechanical perturbations, neuroinflammation, and axonal disruption. This protocol presents a refined stereotactic injection procedure designed to target the LC while minimizing neurotoxicity. By positioning the injection site 0.5 mm lateral to the LC, we effectively deliver viral vectors without directly damaging the region. The protocol outlines the administration of anesthetics, including ketamine and xylazine, ensuring stable conditions during surgery. Key steps include precise head fixation, identification of anatomical landmarks, and careful drilling of the skull to facilitate accurate injections. The use of a beveled needle allows for controlled viral infusion, with a recommended volume of 500 nl per hemisphere at a rate of 50-100 nl/min. Post-operative care, including analgesic administration and monitoring for distress, is emphasized to ensure animal welfare. This optimized approach not only enhances the safety of stereotactic injections in the LC but also supports the integrity of experimental outcomes in neurobiological research.