In 1954, Penfield and Jasper’s findings based on electric stimulation of epileptic patients led them to hypothesize that a sensory representation of the body should be found in the precuneus. They termed this representation the “supplementary sensory” area and emphasized that the exact form of this homunculus could not be specified on the basis of their results. In the decades that followed, their prediction was neglected. The precuneus was found to be involved in numerous motor, cognitive and visual processes, but no work was done on its somatotopic organization. Here we used a periodic experimental design in which 16 human subjects (8 women) moved 20 body parts, to investigate the possible body part topography of the precuneus. We found an anterior-to-posterior, dorsal-to-ventral, toes-to-tongue gradient, in a mirror orientation to the SMA. When inspecting body part specific functional connectivity, we found differential connectivity patterns for the different body parts to the primary and secondary motor areas, parietal and visual areas, and a shared connectivity to the extrastriate body area, another topographically organized area. We suggest that a whole-body gradient can be found in the precuneus and is connected to multiple brain areas with different connectivity for different body parts. Its exact role and relations to the other known functions of the precuneus such as self-processing, motor imagery, reaching, visuo-motor and other body-mind functions should be investigated.
Link to full paper here. Co-authored by Noa Zeharia, Shir Hofstetter, Tamar Flash and Amir Amedi
About Amir Amedi:
Amir Amedi is the Director of the Meir and Ruth Rosental Brain Imaging Lab, IDC Herzliya. He did a PhD in Computational Neuroscience (ICNC, Hebrew University), Postdoctoral and Instructor of Neurology (Harvard Medical School) and was a senior lecturer, Associate Prof. and full Prof. at the Hebrew University. He is adj. Research Prof. at IDV, Sorbonne U. France. He is recipient of The Krill Prize for Excellence in Scientific Research, the Wolf Foundation (2011), the international Human Frontiers Science Program Organization Career Development award (2009), the JSMF Scholar Award in Understanding Human Cognition (2011). He received 2 consecutive ERC grants (www.BrainVisionRehab.com 2013-2018; ExperieSENSE 2018-2023). He is an internationally acclaimed brain scientist with 15 years of experience in the field of brain neuroplasticity and multisensory integration. He is also a co-founder of www.ReNewSenses.com where he is engaged in developing novel Sensory substitution Device and AI algorithms to help the visually and hearing impaired.
For further information, please contact Amedilab@idc.ac.il