Abstract
Previous studies have revealed correspondences between cortical topology and brain function for primary (Hinds et al. 2008; Rajimehr & Tootell 2009) and extrastriate visual cortex (Weiner et al. 2014; Witthoft et al. 2014). Here, we looked at the relationship between cortical folding and regions within macaque inferotemporal cortex (IT) that are selectively active when viewing faces. These regions are located in stereotypical locations across individuals, though correspondence with particular anatomical features has not been previously reported.
We performed functional and anatomical neuroimaging on thirteen macaques. Seven monkeys were raised in environments where they did not see faces and did not develop face-selective domains. Six control monkeys were raised with normal visual experience of faces and developed face-selective domains. Face-selectivity was probed in a localizer scan session. To measure cortical topology, surface models were reconstructed for each monkey from anatomical volumes.
We reveal a structure-function relationship between cortical folding in the superior temporal sulcus (STS) and the location of the middle face(-selective) patch (ML). Within the STS, we identified several “bumps” (convexities) in consistent locations across individuals. In control monkeys, ML was localized to one particular bump within central IT, demonstrating that topological features of the STS can serve as landmarks for functional specialization. This bump was present at birth and existed in monkeys that lacked face-selective domains. These results demonstrate that cortical folding may predict the location of functional specializations in IT but are not sufficient for their development. These “bumps” may not be directly related to face-selectivity, but rather, likely emerge in utero along with early architecture such as retinotopic maps, which also predict where face domains develop (Arcaro et al. 2017). Such a relationship between cortical folding and retinotopy may emerge from general mechanisms such as mechanical pressures that preserve connections across retinotopically matched regions (Van Essen 1997).