Imageless imagery in aphantasia revealed by early visual cortex decoding

DOI: 10.1016/j.cub.2024.12.012

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Chang, S., Zhang, X., Cao, Y., Pearson, J., & Meng, M. (2025). Imageless imagery in aphantasia revealed by early visual cortex decoding. Current Biology, 35(3), 591–599.e4. doi:10.1016/j.cub.2024.12.012

Abstract

Activity in the early visual cortex is thought to tightly couple with conscious experience, including feedback-driven mental imagery. However, in aphantasia (a complete lack of visual imagery), the state of mental imagery, what takes its place, or how any activity relates to qualia remains unknown. This study analyzed univariate (amplitude) and multivariate (decoding) blood-oxygen-level-dependent (BOLD) signals in primary visual cortex during imagery attempts. “Imagery” content could be decoded equally well in both groups; however, unlike in those with imagery, neural signatures in those with validated aphantasia were ipsilateral and could not be cross-decoded with perceptual representations. Further, the perception-induced BOLD response was lower in those with aphantasia compared with controls. Together, these data suggest that an imagery-related representation, but with less or transformed sensory information, exists in the primary visual cortex of those with aphantasia. Our data challenge the classic view that activity in primary visual cortex should result in sensory qualia.

Authors

Shuai Chang3
Xinyu Zhang2
Yangjianyi Cao1
Joel Pearson35
Ming Meng3

What This Study Is About

Researchers investigated whether the brains of people with aphantasia—the inability to create mental images—still process visual information during "imagination" even if the person doesn't see anything. They wanted to know if the primary visual cortex (the brain's main vision center) shows activity that matches what a person is trying to imagine.

How They Studied It

The study involved 15 people with aphantasia and 16 people with typical imagery. Participants lay in an fMRI scanner, which measures brain activity by tracking blood flow. They were asked to either look at specific patterns (perception) or try to imagine those same patterns (imagery) in different parts of their field of vision. Researchers then used computer algorithms to see if they could "decode" or guess what the person was looking at or imagining based solely on their brain activity.

What They Found

Surprisingly, the researchers could accurately decode what people with aphantasia were "imagining" from their brain activity, just as well as they could for the control group. However, there was a major difference: in typical imagers, the brain patterns for imagining a shape looked very similar to the patterns for actually seeing it. In people with aphantasia, these patterns did not match. Their brains were processing the information, but in a "transformed" or different format that didn't link up with actual visual perception.

What This Might Mean

This suggests that aphantasia isn't necessarily a lack of activity in the brain's vision center. Instead, the brain might be representing the information in a way that lacks "sensory qualia"—the actual feeling of seeing an image. It suggests that for a mental image to become conscious, the brain activity needs to closely mimic real seeing, which doesn't happen in aphantasia. One limitation is the small number of participants, which is common in brain-scanning studies but means more research is needed to confirm these patterns.

One Interesting Detail

While typical imagers showed activity on the opposite side of the brain from where they were imagining an object (which is how normal vision works), people with aphantasia showed activity on the same side, suggesting their brains use a fundamentally different "map" for imageless thoughts.

Imageless imagery in aphantasia revealed by early visual cortex decoding

Abstract

Authors

Imageless imagery in aphantasia revealed by early visual cortex decoding

Abstract

Authors

Imageless imagery in aphantasia revealed by early visual cortex decoding

Abstract

Authors

Imageless imagery in aphantasia revealed by early visual cortex decoding

Abstract

Authors

What This Study Is About

How They Studied It

What They Found

What This Might Mean

One Interesting Detail

What This Study Is About

How They Studied It

What They Found

What This Might Mean

One Interesting Detail

Joel Pearson

Merlin Monzel

Adam Zeman

Rebecca Keogh

Martin Reuter

Juha Silvanto

Paolo Bartolomeo

Carla Dance

Jianghao Liu

Fraser Milton