Spikiness and animacy as potential organising principles of human ventral visual cortex

Considerable research has been devoted to understanding the fundamental organising principles of the ventral visual pathway. A recent study revealed a series of 3–4 topographical maps arranged along the macaque inferotemporal (IT) cortex. The maps articulated a two-dimensional space based on the spikiness and animacy of visual objects, with ‘inanimate-spiky’ and 'inanimate-stubby’ regions of the maps constituting two previously unidentified cortical networks. The goal of our study was to determine whether a similar functional organisation might exist in human IT. To address this question, we presented the same object stimuli and images from ‘classic’ object categories (bodies, faces, houses) to humans while recording fMRI activity at 7 Tesla. Contrasts designed to reveal the spikiness-animacy object space evoked extensive significant activation across human IT. However, unlike the macaque, we did not observe a clear sequence of complete maps, and selectivity for the spikiness-animacy space was deeply and mutually entangled with category-selectivity. Instead, we observed multiple new stimulus preferences in category-selective regions, including functional sub-structure related to object spikiness in scene-selective cortex. Taken together, these findings highlight spikiness as a promising organising principle of human IT and provide new insights into the role of category-selective regions in visual object processing.

Methods
This dataset contains anatomical and functional MRI data from 10 human subjects. All neuroimaging data are included in their raw form. Additionally, anatomical data have been preprocessed and parcellated using FreeSurfer (Dale et al. 1999; Fischl et al. 1999), specifically, using the recon-all function. Region of interest masks were created from the Harvard Oxford Cortical Structural Atlas or taken from a probabilistic retinotopic atlas (Wang et al., 2015) and are in standard MNI152 2mm space.