High-resolution fMRI investigations of the fingertip somatotopy and variability in BA3b and BA1 of the primary somatosensory cortex. (17th December 2016)

• Record Type: Journal Article
• Authors: Pfannmöller, Jörg Peter; Greiner, Marvin; Balasubramanian, Mukund; Lotze, Martin
• Is Part Of: Neuroscience. Volume 339(2016)
• Page Start: 667
• Page End: 677
• Publication Date: 2016-12-17
• Subjects: ° degree -- 3D three dimensional -- A Anterior -- BA Brodmann Area -- BA1 Brodmann Area 1 -- BA3b Brodmann Area 3b -- BBR boundary-based register -- BOLD blood oxygenation level-dependent -- CRPS complex regional pain syndrome -- D1 thumb -- D2 index finger -- D3 middle finger -- FDR False Discovery Rate -- fMRI functional magnetic resonance imaging -- FoV field of view -- FSaverage FreeSurfer Group Space Template -- GLM general linear model -- Hz hertz -- IQR inter quartile range -- LOS line of sight -- min minute -- mm millimeter -- MNI Montreal Neurological Institute -- MRI magnetic resonance imaging -- ms millisecond -- n.s. not significant -- p probability -- R right -- S = −log10p FreeSurfer probability -- s second -- S superior -- S1 primary sensory cortex -- TA Total Acquisition Time -- TE Echo Time -- TI Inversion Time -- TR Repetition Time -- V1 primary visual cortex -- α significance level -- Ω hand knob; left-right symmetry -- distance mapping -- fine-scale mapping -- nonlinear normalization -- FreeSurfer -- surface-based; Neurochemistry -- Periodicals; Neurophysiology -- Periodicals; Neurology -- Periodicals; Neurochimie -- Périodiques; Neurophysiologie -- Périodiques; Neurochemistry; Neurophysiology; Electronic journals; Periodicals; Electronic journals; 612.8
• DOI: 10.1016/j.neuroscience.2016.10.036
• Languages: English
• ISSNs: 0306-4522

Abstract

Highlights: Differences in the functional maps of the fingertip somatotopy in BA1 and BA3b. Analysis of the functional and anatomical contribution to the variability in the somatotopy. Evaluation of left-right symmetry in the fingertip somatotopy. Group analysis of the fingertip somatotopy in BA3b and BA1. Maximization of fine-scale mapping and statistical sensitivity in group comparisons. Abstract: The fingertip somatotopy in BA1 and BA3b of monkeys exhibits characteristic differences with a more discrete separation of the body parts in BA3b and a continuous orientation column-like structure in BA1. We present evidence for similar differences in the human somatotopy using BOLD fMRI for the investigations. Though the variability between the individual maps was large, we found a group-wide somatotopic representation in BA3b and BA1. The variability due to anatomical differences was small in our sample. This was demonstrated by comparing exact shortest distances in the individual brains and after nonlinear normalization to the group space template, for the removal of the individual anatomical variability. Distance mapping along Dijkstra paths was found to be a valid approximation to exact shortest paths only in the individual brains. The degree of fine-scale detail mapping was improved if valid surface distances instead of 3D Euclidean distances were applied. A further improvement was achieved by mapping the distances between all neighboring fingertips instead of only the outer fingertips. Taking into account all optimizations we found mirror symmetry of the somatotopy with respect to the interhemispheric gap.