The posterior arcuate fasciculus and the vertical occipital fasciculus.

This letter aims to clarify the definitions of the posterior arcuate fasciculus (pAF) and the vertical occipital fasciculus (VOF). These two tracts are of interest in many different fields, including the neuroscience of language (Catani, Jones, & ffytche, 2005), post-mortem dissection (Vergani, Mahmood, Morris, Mitchell, & Forkel, 2014), reading (Thiebaut de Schotten, Cohen, Amemiya, Braga, & Dehaene, 2014; Yeatman, Rauschecker, & Wandell, 2012), neurosurgery (Bartsch, Geletneky, & Jbabdi, 2013; Martino et al., 2013), and human vision (Takemura et al., 2015; Yeatman et al., 2014). Despite this broad interest, there is not an agreed upon anatomical definition of these two tracts. Here, we use a computational approach to create a reproducible method that delineates these tracts. Some authors describe the pAF and VOF as separate tracts (Catani et al., 2005; Curran, 1909; Yeatman et al., 2014), but there are reasons why the distinction between the pAF and VOF remains unclear. First, Wernicke's original semischematic image of the VOF (Wernicke, 1881) was in unspecified non-human primate and there is only a partial