Tracking the mind’s eyes: Spatiotemporal Dynamics of Domain-General and Domain-Specific Visual Mental Imagery

Abstract

When we relive our memories, enjoy a novel, create a painting, or predict whether our car will fit in a parking spot, we use our “Mind’s Eye” to engage in Visual Mental Imagery (VMI). The current consensus is that VMI depends crucially on early visual areas. By contrast, longstanding evidence from neurological patients demonstrates that vivid VMI is possible even with no contribution from these areas. Instead, VMI can be impaired by left temporal damage. In a meta-analysis of neuroimaging studies, we discovered VMI-associated activity, not only in fronto-parietal areas, where it had been detected by earlier studies, but also in a previously undescribed functional region of the left ventrotemporal cortex, which we have called the Fusiform Imagery Node (FIN). The role of this region in VMI was apparent in a ultra-high field 7T fMRI that showed activation in left-hemisphere fronto-parietal areas, the relevant domain-preferring areas in the ventral temporal cortex partly overlapping with the perceptual domain-preferring areas, and the domain-general FIN. These recent results make this the ideal moment to build a new neurocognitive model of voluntary VMI, reliant on a heterarchical neural architecture that mixes domain-general and domain-specific mechanisms. In this study, we will identify the functional role of cortical nodes in VMI-related networks using MEG in neurotypical participants, and we will ascertain the temporal dynamics of the relevant neural processes associated with domain-specific VMI. Results will be compared and contrasted against predictions from competing models of visual mental imagery, providing new hypotheses for the mechanisms underlying this function, and building a bridge to broader theories of conscious awareness.