What This Study Is About
This scientific commentary discusses a breakthrough study that used brain stimulation to see if people with aphantasia—the inability to create mental images—also have trouble "simulating" physical movements in their minds. It explores whether aphantasia is more than just a lack of visual "pictures" and actually involves a deeper difference in how the brain prepares for action.
How They Studied It
The researchers reviewed a study where participants with either typical imagery or aphantasia performed three tasks: imagining a "pinch" movement (kinaesthetic imagery), watching a video of a pinch (action observation), and visual imagery. Researchers used Transcranial Magnetic Stimulation (TMS)—a non-invasive tool that uses magnetic pulses to stimulate the brain—to measure "corticospinal excitability." This is essentially a measure of how "ready" the brain's motor system is to move.
What They Found
In people with typical imagery, simply imagining a movement or watching someone else do it caused their motor system to "rev up" and become more excitable. However, in people with aphantasia, this response was missing. Their brains did not show increased readiness during these mental tasks. This suggests that for those with aphantasia, the brain may struggle to simulate the physical sensation of moving, not just the visual image of it.
What This Might Mean
These findings suggest that aphantasia is not just a "failure of will" or a lack of awareness, but is tied to specific biological differences in how the brain processes simulations. It indicates that aphantasia might be a "multi-sensory" condition that affects how people imagine touch and movement. However, the commentary notes that future studies should test more people and adjust the timing of the brain pulses to confirm these results.
One Interesting Detail
While aphantasia is often defined by a lack of visual imagery, research suggests it is quite diverse: about 24% of people with aphantasia report a total absence of all mental senses (including sound, touch, and smell), while others may only lack visual "pictures."