Rolf Degen summarizing... Meta-analysis: The images we summon up in our mind's eye do nor tap into the visual perception apparatus at the back of the brain

Visual mental imagery engages the left fusiform gyrus, but not the early visual cortex: A meta-analysis of neuroimaging evidence. Alfredo Spagna et al. Neuroscience & Biobehavioral Reviews, Volume 122, March 2021, Pages 201-217. https://doi.org/10.1016/j.neubiorev.2020.12.029

Highlights

• Models of visual mental imagery highlight the importance of early visual areas.

• Temporal, not occipital lesions impair visual mental imagery in neurological patients.

• We performed an ALE meta-analysis of fMRI studies of visual mental imagery.

• Visual mental imagery engages fronto-parietal networks and the left fusiform gyrus.

• Our results reconcile neuroimaging evidence with cognitive neurology.

Abstract: The dominant neural model of visual mental imagery (VMI) stipulates that memories from the medial temporal lobe acquire sensory features in early visual areas. However, neurological patients with damage restricted to the occipital cortex typically show perfectly vivid VMI, while more anterior damages extending into the temporal lobe, especially in the left hemisphere, often cause VMI impairments. Here we present two major results reconciling neuroimaging findings in neurotypical subjects with the performance of brain-damaged patients: (1) A large-scale meta-analysis of 46 fMRI studies, of which 27 investigated specifically visual mental imagery, revealed that VMI engages fronto-parietal networks and a well-delimited region in the left fusiform gyrus. (2) A Bayesian analysis showed no evidence for imagery-related activity in early visual cortices. We propose a revised neural model of VMI that draws inspiration from recent cytoarchitectonic and lesion studies, whereby fronto-parietal networks initiate, modulate, and maintain activity in a core temporal network centered on the fusiform imagery node, a high-level visual region in the left fusiform gyrus.

Keywords: Fronto-parietal networksAttentionWorking memoryFusiform gyrusTemporal lobe