Validation of tractography against in vivo tracing in the macaque visual system: effect of distance correction

Validation of diffusion imaging has proved difficult due to the lack of an adequate gold-standard. In this work, the macaque visual system is used as a model, in which due to an extensive literature of in-vivo and post-mortem tracer studies, true connections are well-established. We performed probabilistic tractography on diffusion imaging data from two in-vitro macaque brains, and comparisons were made between identified connections at different thresholds of connection strength, and connections identified in the visual system wiring map of Felleman & van Essen. The effects of streamline-length based correction of the distance bias of probabilistic tractography were also explored