Excited to share our (Flo Martinez Addiego @yuqiliu1179.bsky.social @culhamari-lab.bsky.social) paper, now published in PNAS!

www.pnas.org/doi/10.1073/...
(or an easier read on medicine.georgetown.edu/news-release... )

Now out in @natneuro.nature.com

What happens to the brain’s body map when a body-part is removed?

Scanning patients before and up to 5 yrs after arm amputation, we discovered the brain’s body map is strikingly preserved despite amputation

www.nature.com/articles/s41593-025-02037-7

🧵1/18

These findings provide novel evidence for long-range motor reorganization and visual recruitment subsequent to S1 damage in human subjects, adding knowledge regarding the differential roles across motor regions in sensorimotor integration.

Finally, both LS and RF showed greater activity in middle occipital gyrus relative to controls, suggesting a potential reliance on visual imagery in the face of degraded sensory feedback.

In contrast, RF, who had a small island of spared ipsilesional (left) S1 that was active during stimulation of the hand, showed greater activation in contralesional (right) S1 for movement versus rest, demonstrating cross-hemispheric reorganization.

These findings provide evidence for a potential reweighting of the motor network after S1 damage, such that the noisy sensory information leads to inhibition of sensory prediction mechanisms in the cerebellum.

In one individual (LS) with near complete damage to the S1 hand area, moving the contralesional right hand elicited stronger activation in right putamen relative to age-matched controls, and surprisingly, *deactivation* in right cerebellum (Lobule VI).

As expected, both individuals showed elevated tactile detection thresholds and distorted tactile localization on the contralesional right hand, and accordingly relied heavily on vision when moving the hand. Otherwise they had preserved motor abilities.

New preprint! Work since I was with @jaredmedina.bsky.social and in collaboration with @jeffmyau.bsky.social, @cogsimon.bsky.social, and H. Branch Coslett. We studied motor and somatosensory reorganization in two cases in which left S1 was severely damaged but M1 was intact. doi.org/10.1101/2025...