Reconstructing imagined letters from early visual cortex reveals tight topographic correspondence between visual mental imagery and perception

DOI

Visual mental imagery is the quasi-perceptual experience of “seeing in the mind’s eye”. While a tight correspondence between imagery and perception in terms of subjective experience is well established, their correspondence in terms of neural representations remains insufficiently understood. In the present study, we exploit the high spatial resolution of functional magnetic resonance imaging (fMRI) at 7T, the retinotopic organization of early visual cortex, and machine-learning techniques to investigate whether visual imagery of letter shapes preserves the topographic organization of perceived shapes. Sub-millimeter resolution fMRI images were obtained from early visual cortex in six subjects performing visual imagery of four different letter shapes. Predictions of imagery voxel activation patterns based on a population receptive field-encoding model and physical letter stimuli provided first evidence in favor of detailed topographic organization. Subsequent visual field reconstructions of imagery data based on the inversion of the encoding model further showed that visual imagery preserves the geometric profile of letter shapes. These results open new avenues for decoding, as we show that a denoising auto encoder can be used to pretrain a classifier purely based on perceptual data before fine-tuning it on imagery data. Finally, we show that the auto encoder can project imagery-related voxel activations onto their perceptual counterpart allowing for visually recognizable reconstructions even at the single-trial level. The latter may eventually be utilized for the development of content-based BCI letter-speller systems.

Identifier
DOI https://doi.org/10.34894/ITWFZP
Related Identifier https://doi.org/10.1007/s00429-019-01828-6
Metadata Access https://dataverse.nl/oai?verb=GetRecord&metadataPrefix=oai_datacite&identifier=doi:10.34894/ITWFZP
Provenance
Creator Senden, Mario ORCID logo; Emmerling, Thomas C. ORCID logo; van Hoof, Rick ORCID logo; Frost, Martin A.; Goebel, Rainer ORCID logo
Publisher DataverseNL
Contributor Senden, Mario; faculty data manager FPN
Publication Year 2020
Rights info:eu-repo/semantics/restrictedAccess
OpenAccess false
Contact Senden, Mario (Maastricht University); faculty data manager FPN (Maastricht University)
Representation
Resource Type fMRI data; Dataset
Format application/zip
Size 14282423; 191284518; 2595891813; 3640350603; 189268342; 2456073049; 2727742321; 187764215; 2619096907; 2918627375; 4626431934; 4596368856; 4966917911; 5267708032
Version 1.0
Discipline Agriculture, Forestry, Horticulture, Aquaculture; Agriculture, Forestry, Horticulture, Aquaculture and Veterinary Medicine; Life Sciences; Social Sciences; Social and Behavioural Sciences; Soil Sciences