title: New whole-body sensory-motor gradients revealed using phase-locked analysis and verified using multivoxel pattern analysis and functional connectivity.
abstract: Topographic organization is one of the main principles of organization in the human brain. Specifically, whole-brain topographic mapping using spectral analysis is responsible for one of the greatest advances in vision research. Thus, it is intriguing that although topography is a key feature also in the motor system, whole-body somatosensory-motor mapping using spectral analysis has not been conducted in humans outside M1/SMA. Here, using this method, we were able to map a homunculus in the globus pallidus, a key target area for deep brain stimulation, which has not been mapped noninvasively or in healthy subjects. The analysis clarifies contradictory and partial results regarding somatotopy in the caudal-cingulate zone and rostral-cingulate zone in the medial wall and in the putamen. Most of the results were confirmed at the single-subject level and were found to be compatible with results from animal studies. Using multivoxel pattern analysis, we could predict movements of individual body parts in these homunculi, thus confirming that they contain somatotopic information. Using functional connectivity, we demonstrate interhemispheric functional somatotopic connectivity of these homunculi, such that the somatotopy in one hemisphere could have been found given the connectivity pattern of the corresponding regions of interest in the other hemisphere. When inspecting the somatotopic and nonsomatotopic connectivity patterns, a similarity index indicated that the pattern of connected and nonconnected regions of interest across different homunculi is similar for different body parts and hemispheres. The results show that topographical gradients are even more widespread than previously assumed in the somatosensory-motor system. Spectral analysis can thus potentially serve as a gold standard for defining somatosensory-motor system areas for basic research and clinical applications.
authors.affiliation: The Edmond and Lily Safra Center for Brain Sciences (ELSC) and Medical Neurobiology Department of IMRIC and The Hebrew University of Jerusalem Medical School and Hebrew University of Jerusalem, Jerusalem 91220, Israel, Sorborne Universités, UPMC Univ Paris 06, Institute de la Vision, UMR_S968, Paris, F-75012, France.
authors.forename: Noa
authors.initials: N
authors.lastname: Zeharia
authors.affiliation: The Edmond and Lily Safra Center for Brain Sciences (ELSC) and Medical Neurobiology Department of IMRIC and The Hebrew University of Jerusalem Medical School and University College London, 17 Queen Square, London WCIN 3AR, United Kingdom, and.
authors.forename: Uri
authors.initials: U
authors.lastname: Hertz
authors.affiliation: Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot 76 100, Israel.
authors.forename: Tamar
authors.initials: T
authors.lastname: Flash
authors.affiliation: The Edmond and Lily Safra Center for Brain Sciences (ELSC) and Medical Neurobiology Department of IMRIC and The Hebrew University of Jerusalem Medical School and Hebrew University of Jerusalem, Jerusalem 91220, Israel, Sorborne Universités, UPMC Univ Paris 06, Institute de la Vision, UMR_S968, Paris, F-75012, France, amir.amedi@ekmd.huji.ac.il.
authors.forename: Amir
authors.initials: A
authors.lastname: Amedi
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000098:blood supply / Q000502:physiology; D001931:Brain Mapping; D005260:Female; D018594:Human Body; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000098:blood supply / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D012044:Regression Analysis; D012677:Sensation / Q000502:physiology*; D012683:Sensory Deprivation; D013057:Spectrum Analysis; D060388:Support Vector Machine
chemical_list: D010100:Oxygen
keywords: functional connectivity; motor system; spectral analysis; topography