# From imaging to precision: low cost and accurate determination of stereotactic coordinates for brain surgery Sapajus apella using MRI

## TL;DR

This paper introduces a low-cost, accurate method using MRI to determine brain surgery coordinates in capuchin monkeys, improving precision over traditional brain atlas methods.

## Contribution

A novel, affordable MRI-based protocol for deriving individual stereotactic coordinates in Sapajus apella monkeys.

## Key findings

- The protocol uses a 3D-printed head-holder and fiducial markers for MRI imaging.
- Open-source software improves anatomical targeting and neurosurgical experiment design.
- The method is adaptable for other nonhuman primate species lacking brain atlases.

## Abstract

The capuchin monkey (Sapajus apella), a New World monkey species, exhibits prominent characteristics that make it an ideal model for neuroscience research. These characteristics include its phylogenetic traits, telencephalization coefficient, anatomical structures and pathways, genetic profile, immune responses, cognitive abilities, and complex behavioral repertoires. Traditionally, methodologies for stereotactic neurosurgery in research models have relied on the use of brain atlases. However, this approach can lead to errors due to the considerable variation in brain size and shape among individual monkeys. To address this issue, we developed a protocol for deriving individual coordinates for each monkey using a straightforward and relatively inexpensive method involving MRI imaging. Our protocol utilizes a specially designed, 3D-printed stereotactic head-holder that is safe to use with an MR magnet, non-invasive placement of fiducial markers, and post-processing with open-source software. This approach enhances MRI data visualization, improves anatomical targeting, and refines the design of neurosurgical experiments. Our technique could also prove beneficial in other areas of neuroscience research that require accurate calculation of stereotaxic coordinates. Furthermore, it could be useful for other nonhuman primate species for which brain atlases are typically unavailable.