Researchers Map Human Motor Cortex With 20 Arrays, Challenging Classic Homunculus
Updated
Updated · Nature.com · Jun 17
Researchers Map Human Motor Cortex With 20 Arrays, Challenging Classic Homunculus
3 articles · Updated · Nature.com · Jun 17
Summary
Using 20 microelectrode arrays in 8 people with paralysis, researchers built what they call the first single-neuron-resolution map of the human precentral gyrus, finding whole-body movement signals at every sampled site.
The data showed body-part representations were highly intermixed rather than neatly separated, though dorsal regions still favored arm movements and ventral regions favored orofacial activity in line with the classic motor homunculus.
Two speech-preferring zones emerged, with a broadly tuned orofacial area between them; one superior ventral array decoded 45 movements with 86% average accuracy, suggesting overlooked targets for brain-computer interfaces.
Across the cortex, homologous limb movements such as toe curl and hand close had correlated neural patterns, supporting a compositional, behavior-centered code rather than a simple body-part map.
The findings could reshape intracortical BCI placement for restoring speech and movement, though the study was limited to 8 participants with paralysis rather than able-bodied volunteers.
If the brain’s classic body map is wrong, how will we control robotic limbs and restore speech with our thoughts?
Could one brain implant soon restore movement to all four limbs and even a person's voice?
With China approving the first commercial BCI, can this new brain map help the U.S. win the neurotechnology race?
The Somato-Cognitive Action Network (SCAN): A Paradigm Shift in Parkinson’s Disease Mechanisms, Motor Cortex Organization, and Neurotherapeutics
Overview
A major breakthrough in Parkinson's disease research has revealed the critical role of the Somato-Cognitive Action Network (SCAN). This discovery, soon to be published in Nature, emerged from the convergence of independent research efforts, including a decade-long investigation by Hesheng Liu's team into how deep-brain stimulation (DBS) alleviates symptoms. By connecting previously unexplained patterns in the primary motor cortex to SCAN, researchers have gained a clearer understanding of Parkinson's underlying mechanisms. This insight not only explains how current treatments work but also opens new possibilities for targeted therapies, marking a significant step forward in both science and clinical care.