ICYMI: Mental Map of the Body Stays Consistent After Amputation

New research finds the brain’s mental map of the body — housed in the primary somatosensory cortex — doesn’t reorganize itself following limb loss, contrary to popular belief.

Pixabay

New research suggests the brain’s detailed sensory map of the body doesn’t change much even after a person loses a limb. This finding upends a long-standing belief that this map reorganizes itself following amputation. The groundbreaking study was published August 21 in Nature Neuroscience.

Our bodies are mapped out in the brain’s primary somatosensory cortex, which processes information like touch, pain, and temperature. Conventional wisdom suggested areas of the cortex corresponding to an amputated body part would shift to an adjacent part on the map to fill in the gap after amputation.

For this study, a group of U.K.-based researchers documented cortical activity using fMRI among three participants before they underwent arm amputation. Five years following the procedure, their mental maps worked the same as they did beforehand, including in the areas representing their removed limbs. Researchers found part of the cortex representing the patients’ lips, a neighboring area on the map unaffected by surgery, also remained static.

Big Picture: This revelation could have implications for medical interventions designed for people who have lost a limb. A better understanding of how the brain actually maps the body could inform approaches to treating phantom pain following amputation, or for designing novel prosthetics which could be connected to the primary somatosensory cortex, according to Nature. Given the study's limited sample size and type, however, more research is necessary to expand on these findings and assess whether they apply to other types of amputations.

Read More: The brain’s map of the body is surprisingly stable — even after a limb is lost. Nature

More Top Stories 

• Lithium might play a key role in protecting brain health as we age. CNN
• Personalized deep brain stimulation implants helped reduce chronic pain severity among patients whose condition was previously considered untreatable. New Scientist
• Long thumbs are linked to larger brains in primates — including humans. The Guardian
• In a first, several patients living with paralysis successfully had their thoughts translated to text on a screen in real time using an experimental neural prosthetic. Scientific American
• Female prairie voles genetically modified to lack oxytocin receptors don’t form strong “friendships” with their peers, suggesting oxytocin plays a key role in forming those bonds. Popular Science
• People in their 80s with robust memories — dubbed “superagers” — display anatomical brain differences compared to others their age, including resistance to amyloid plaques associated with Alzheimer’s disease. STAT News
• Among males of a fruit fly species known for offering their vomit during courtship, researchers identified neurons tied to digestion which may have played a key role in the evolution of this behavior. Science News
• Feline dementia shares a similar pathology to Alzheimer’s disease in people, meaning older cats may offer an untapped resource for studying the condition and novel therapeutics to treat it. BBC Science Focus
• Using a miniature model of the human brain called an organoid, researchers determined microglia play a significant role in driving healthy interneuron development in utero. Live Science

About the Author

Bella Isaacs-Thomas

Bella is the Staff Writer and Editor for BrainFacts. She previously worked as a digital science reporter at PBS NewsHour, where she was named a fellow in the 2022-2023 class of the National Science-Health-Environment Reporting Fellowships (SHERF) and earned a 2021 D.C. Science Writers Association Newsbrief Award for writing. She graduated from the University of Michigan with a bachelor's degree in 2018.