Absence of shared representation in the visual cortex challenges unconscious imagery in aphantasia

Abstract

Aphantasia is defined as the absence (or near-absence) of imagery experience, most commonly in but not necessarily limited to the visual modality. While the neural and cognitive underpinnings of aphantasia remain hotly debated (see Zeman1 for a recent review), a proposal that has recently gained attention is that people with aphantasia may have unconscious mental imagery2, meaning that despite lacking the experience associated with imagery, they may still possess the relevant neural activity. A recent article in Current Biology by Chang et al.3 reported finding ‘imageless imagery’ in aphantasic subjects, thus seemingly supporting this view. However, we argue here that the representations found in aphantasic subjects by Chang et al.3, as well as in other studies (e.g., by Liu et al.4,5), should not be viewed as unconscious imagery because they fail to show the perception-like pattern usually associated with mental imagery.

What This Study Is About

This study investigates whether people with aphantasia—the inability to create mental images—might still have "unconscious" mental imagery happening in their brains. The researchers looked at whether the brain activity of aphantasics during imagery tasks truly mimics the patterns seen during actual seeing (perception).

How They Studied It

The researchers analyzed data from previous neuroimaging studies that used fMRI (brain scans) to monitor the visual cortex—the part of the brain that processes what we see. They compared two groups: "typical imagers" (people who can see pictures in their mind) and "aphantasics." They specifically looked for three things: if the visual cortex was active, if that activity contained specific details about the object being imagined, and if those brain patterns matched the patterns created when the person was actually looking at the object.

What They Found

While people with aphantasia do show activity in their visual cortex when trying to imagine something, and that activity contains some specific details, it does not match the brain patterns used for real seeing. In typical imagers, the brain "recycles" the same patterns for both seeing and imagining. In aphantasics, these patterns are different. This suggests that even if there is activity in the visual brain, it isn't "unconscious imagery" because it doesn't look like the brain's version of a picture.

What This Might Mean

The findings suggest that aphantasia isn't just "blind" imagery; instead, people with aphantasia may use entirely different mental strategies to think about objects. Their brains might be processing information in a non-visual or more abstract way, even when using the visual parts of the brain. This challenges the idea that everyone’s brain tries to "picture" things the same way.

One Interesting Detail

The researchers found that in aphantasics, the brain activity during imagery tasks was often stronger on the same side of the brain as the object they were thinking about. This is the opposite of how normal vision works, where the left side of the brain handles the right side of your vision and vice versa.

Absence of shared representation in the visual cortex challenges unconscious imagery in aphantasia

Abstract

Authors

Absence of shared representation in the visual cortex challenges unconscious imagery in aphantasia

Abstract

Authors

Absence of shared representation in the visual cortex challenges unconscious imagery in aphantasia

Abstract

Authors

Absence of shared representation in the visual cortex challenges unconscious imagery in aphantasia

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