Simplified adaptor for stereotactic surgery in non-human primates.

BACKGROUND: It is challenging for researchers performing stereotactic procedures to transition from small animals to non-human primate (NHP) experiments. The NHP stereotactic atlas is based on ear-bar zero (EBZ), which is an anatomical reference frame that is not visible during surgery. Most current NHP stereotactic systems require high-cost MRI or CT imaging and complex computer processing to determine the stereotactic coordinates, limiting the procedure to those with significant expertise.

NEW METHOD: We have designed a simplified adaptor consisting of a circular arc for coronal tilt, a carrier for electrodes or cannulas, and an anchor to attach the adaptor to a conventional stereotactic frame. Our adaptor allows easy identification of the EBZ with the help of an anchor notch, and provides digital distance sensors without the need for imaging data or computer processing. Our system enables the use of trajectories that avoid injury to important structures and vessels.

RESULTS: We tested the accuracy of our system using simulated targeting with phantoms, and demonstrated sub-millimeter accuracy. Infusion of methylene blue also showed satisfactory staining in target structures deep in the brain.

COMPARISON WITH EXISTING METHODS: This system does not require high-cost imaging and extra training to determine EBZ. Once EBZ is set automatically by the system itself, targeting is similar to that in small animal stereotactic procedure.

CONCLUSION: Our simple adaptor will aid researchers who plan to conduct experiments involving stereotactic surgery in NHPs.