Distinct distributed networks support visual and linguistic mental imagery

Poster Session F - Tuesday, April 16, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Nathan Anderson¹ (nathan.anderson@northwestern.edu), Joseph Salvo¹, Maya Lakshman¹, Jonathan Smallwood², Rodrigo Braga¹; ¹Northwestern University, ²Queen's University

Mental imagery is the process of experiencing sensory information in the absence of a direct external stimulus. Individual-level precision fMRI studies have provided evidence that a distinct network (“DN-A”) can be defined within the canonical default network which shows increased activity when mentalizing scenes, especially when these are reported to be visually vivid. Here, we examined the involvement of brain networks in the phenomenological experience of imagination across other domains. Eight healthy adult participants performed a mental imagery task, imagining various scenarios and rating each on multiple attributes, including visual and auditory vividness, language content, spatial cognition, difficulty, etc. Participants also completed a passive fixation task, used to estimate brain networks in each individual based on functional connectivity. Extensive (7.6 hrs) of fMRI data was collected from each participant. A principal component analysis of behavioral ratings from each trial revealed a principal component (PC1) that represented the main effect of imagining across all trials. Trial-wise regression of PC1 loadings against evoked responses revealed that this component corresponded to activity within DN-A. A second component (PC2) differentiated highly visual/scene-related versus highly auditory/linguistic trials. This component was associated with anticorrelated activity between DN-A and the language network. Our results indicate that, while DN-A appears to play a prominent role in imagining, its involvement is greater for imagining scenes, while other distributed networks (e.g., the language network) are engaged when imagining other types of content. These results also demonstrate the utility of collecting significant amounts of neuroimaging and behavioral data for examining imagination.

Topic Area: OTHER