An MRI based average macaque monkey stereotaxic atlas and space (MNI monkey space)

In studies of the human brain, a standard stereotaxic space such as the Montreal Neurological Institute (MNI space) is widely used to provide a common reference for the three-dimensional localization of functional activation foci and anatomical structures, enabling the comparison of results obtained across different studies. Here we present a standard macaque monkey brain MRI template that offers a common stereotaxic reference frame to localize anatomical and functional information in an organized and reliable way for comparison across individual monkeys and studies. We have used MRI volumes from a group of 25 normal adult macaque monkeys (18 cynomolgus and 7 rhesus) to create a common standard macaque monkey brain as well as atlases for each of these species separately. In addition, the digital macaque monkey volume was subjected to 3D volumetric analysis and comparison of brain structures between the individual brains and the average atlas. Furthermore, we provide a means of transforming any macaque MRI volume into MNI monkey space coordinates in 3D using simple web based tools. Coordinates in MNI monkey space can also be transformed into the coordinate system of a detailed neuroanatomical paper atlas (Paxinos et al., 2008), enabling researchers to identify and delineate cortical and subcortical structures in their individual macaque monkey brains.