Abstract We compare the major white matter tracts in human and macaque occipital lobe using diffusion MRI. The comparison suggests similarities but also significant differences in spatial arrangement and relative sizes of the tracts. There are several apparently homologous tracts in the two species, including the vertical occipital fasciculus (VOF), optic radiation, forceps major, and inferior longitudinal fasciculus (ILF). There is one large human tract, the inferior fronto-occipital fasciculus, with no corresponding fasciculus in macaque. The macaque VOF is compact and its fibers intertwine with the dorsal segment of the ILF, but the human VOF is much more elongated in the anterior-posterior direction and may be lateral to the ILF. These similarities and differences will be useful in establishing which circuitry in the macaque can serve as an accurate model for human visual cortex. Contact information Hiromasa Takemura, Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology, and Osaka University, Japan htakemur@nict.go.jp Author contribution Designed the study: HT FP BAW. Performed the experiments. HT FP GAK SML JS FQY DAL WAF NKL. Analyzed the data. HT FP KSW MAB BAW. Contributed analysis tools. FP KSW MAB. Wrote the paper. HT FP KSW BAW.

Occipital white matter tracts in human and macaque