Seeing more than schemas: the vmPFC represents imagery- rich mental scenarios

Abstract

Mental imagery varies dramatically across individuals, from vivid scene construction to the complete absence of visual experience, as seen in aphantasia. While the ventromedial prefrontal cortex (vmPFC) is traditionally associated with abstract, schematic representations, emerging theories suggest it may also contribute to constructing vivid, visual mental content. To test this, we developed a novel 7T fMRI experiment varying imagery demands across conditions: Prior to scanning, participants memorized richly detailed scenarios, more constrained, stationary objects, and finally semantic definitions for each of three abstract German words (e.g., hope). During fMRI and eye-tracking, the same word was presented across trials, but participants vividly re-engaged with one of three distinct representations (i.e., scenarios, objects, and definitions), allowing for comparison across richly different cognitive modes triggered by identical visual input. Univariate analyses confirmed previous findings; highlighting the roles of the vmPFC, hippocampus, parahippocampal cortex, and visual-perceptual cortex in imagery-rich scenario construction. We further performed multivoxel pattern analysis (MVPA) to examine distributed neural representations, which can reveal the informational content of mental imagery beyond activation magnitude. Critically, the vmPFC was the only brain region where MVPA classifier accuracy was higher for scenario construction than for object and abstract conditions, directly supporting our hypothesis that the vmPFC encodes imagery-rich details rather than solely abstract, schematic information. Eye movement variability also distinguished between conditions. These findings advance our understanding of vmPFC function, emphasising its role in representing vivid mental content. HighlightsO_LI{middle dot} vmPFC distinctly represents imagery-rich scenarios in MVPA analysis C_LIO_LIUnivariate fMRI reveals increased HC and PHC activity during scenario construction C_LIO_LIEye movements vary by imagery type, distinguishing scenarios from objects and definitions C_LI