Stereotaxic Surgery in Infant Mice and Postoperative Care

Understanding the developmental, cellular, and circuit processes across the postnatal period is crucial for elucidating the complexities of brain development and its impact on behavioral and social maturation. The transition from infant to adulthood involves significant neurobiological changes, including synaptic pruning and myelination, which are fundamental for cognitive abilities, emotional regulation, and social interactions. Studying brain development in prepubertal mice enables researchers to identify critical periods that support healthy brain growth and to establish timely interventions for neurodevelopmental disorders. To precisely dissect brain function, stereotaxic surgery has been a pivotal technique in neuroscience research, offering unparalleled precision in targeting brain regions of interest and allowing the delivery of viral agents. Even though stereotaxic surgeries in adult mice are widely implemented across neurobiology labs, there are very limited guidelines for performing stereotaxic surgeries in prepubertal mice, as well as crucial postoperative care to ensure the infant can be successfully reintroduced to its dam and littermates. Here, we describe a protocol for stereotaxic surgery and viral injection in infant (P11-P12) mice, highlighting anesthesia and analgesia delivery, considerations for postoperative care, and differences from stereotaxic surgery in adults. This protocol can be implemented in any brain region of interest by updating the desired target coordinates and can be modified for brain targeting at later stages in postnatal development, such as during the juvenile period (P15-P30). Overall, this protocol provides an entry point for the study of postnatal brain development and function.