Two dominant axes structure high-dimensional object representations in the human ventral temporal cortex

Abstract

The ventral temporal cortex is critical for visual object recognition, yet the principles organising its representations remain unclear. Using ultra-high-field 7T fMRI and dense sampling of 1,854 object concepts, we applied exploratory factor analysis to multivoxel response patterns to estimate the main axes of representational variation. Despite high dimensionality, over half of the explainable variance concentrated along two dominant axes: a continuum spanning objects of high biological salience, and a second integrating spatial context, physical scale, and manipulability. Importantly, neither reduced to a single semantic label, instead reflecting mixtures of visual and conceptual properties. Together they defined a triangular geometry, anchored by animal-, furniture- and food-related objects, stable across participants and two independent datasets, that mapped onto a lateral-to-medial cortical gradient, with category-selective regions emerging as local peaks within a broader continuum. These findings reveal that high-dimensional object representations in the ventral temporal cortex are structured by a small number of interpretable axes.