Aphantasia vs visual activity in the brain

1 min readByNeal White

According to an article over on TheGuardian.com, “Short films made from brain activity of mice aim to show how they see world”, scientists are able to extract brain signals and show what a mouse is actually seeing.

What I found particularly interesting is that one worried scientist voiced a concern that I think aphantasia would render moot (offers complete protection). I think all they'd get from me is blackness…

“The risk in humans would be if you can reconstruct not what they see, but what they imagine,” he said. “We don’t necessarily want to share everything that’s happening in our heads,” he added. “The privacy of our neural data is important and will become more and more important.”

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Josh Camden•recently•edited

Actually my understanding that this is not only possible but already happening with humans. A human is shown a series of images then told to imagine it, in the image absence. They're connected to a brain scanner, pushing data to an ai. Eventually the ai sees a pattern is able to more and more accurately predict what the subject is thinking providing more and more data is provided. Science fiction remains so right up to and beyond the day its already become fact.

Liên Vũ Kim•recently•edited

This is a bit far-fetched, since whoever think reconstructing what a person see is the same thing that what they imagine must have equated the two together metaphysically, even though seeing is an external process while imagining is internal.

Neal White•recently•edited

Good point. I have no idea if it's actually possible, but my thinking is that if scientists are able to somehow tap into the imagined visuals of a typical person, they still wouldn't be able to decipher what I'm thinking of, since there's no image in my mind's eye.

Alice Grebanier•recently•edited

Scientists already use machine learning to create models of fMRI scans of the visual cortex during visual perception and imagination. My impression is that these models can work pretty well for multiple scans from the same person, but nowhere near so well between people. Interestingly in a recent paper, it was found that the accuracy of the predictions of what was seen or imagined (meaning accuracy above chance) was about the same for visualizers and aphants when the models were applied only to perception or only to imagination. However, the cross-task accuracy (visualization vs perception) was better than chance only for the visualizers. For aphants, the cross-task accuracy was no better than chance. (See https://doi.org/10.1016/j.cub.2024.12.012) The visual images used in this study were very simple, but there still are some implicatons. Just because you do not experience any visualization when you try to imagine something doesn't mean that your visual cortex is not doing anything. So maybe it could be possible to read someone's mind, even if they were aphantasic, if you had a library of fMRI scans taken when they were imagining different types of things. Maybe not today (who is going to sit in an fMRI for this purpose anyway???), but who knows what the future may bring.

Ravi M.•recently•edited

My intuition also agrees that having aphantasia does not necessarily mean your thoughts may not have visual information to decode. I just posted separately that I have been able to unlock the ability to visualize a small number of times in my life. This suggests that the machinery is there and can function correctly, but somehow I usually don't have access to it. Hence, there may be visual information that could be decoded, even though I have aphantasia.

Ravi M.•recently•edited

As a side note, even if mental imagery is not decoded from one's thoughts, it is likely that other thoughts such as an internal monologue could still be decoded, in turn revealing one's thoughts. I think safeguarding the privacy of people's neural data is a real concern.