000231975 001__ 231975
000231975 005__ 20181203024839.0
000231975 0247_ $$2doi$$a10.1016/j.neuroimage.2017.06.021
000231975 022__ $$a1095-9572
000231975 02470 $$2ISI$$a000414073100040
000231975 037__ $$aARTICLE
000231975 245__ $$aAnatomical and functional properties of the foot and leg representation in areas 3b, 1 and 2 of primary somatosensory cortex in humans: A 7T fMRI study
000231975 260__ $$bElsevier$$c2017$$aSan Diego
000231975 269__ $$a2017
000231975 300__ $$a15
000231975 336__ $$aJournal Articles
000231975 520__ $$aPrimary somatosensory cortex (S1) processes somatosensory information and is composed of multiple subregions. In particular, tactile information from the skin is encoded in three subregions, namely Brodmann areas (BAs) 3b, 1 and 2, with each area representing a complete map of the contralateral body. Although, much is known about the somatotopic organization of the hand in human S1, less research has been carried out regarding the somatotopic maps of the foot and leg in S1. Moreover, a latero-medial S1 organization along the superior part of the postcentral gyrus has been reported when moving from hip to toes, yet to date there is no study investigating leg/foot maps within the different subregions of S1. Using ultra-high field MRI (7T), we mapped six cortical representations of the lower limb (hip to toes) at the single subject level and performed this analysis separately for BAs 3b, 1 and 2. Analyzing the BOLD responses associated with tactile stimulations of the mapped foot and leg regions on each side, we quantified the extent and the strength of activation to determine somatotopic organization. In addition, we investigated whether each mapped representation also responded to the stimulation of other body parts (i.e. response selectivity) and conducted dissimilarity analysis relating these anatomical and functional properties of S1 to the physical structure of the lower limbs. Our data reveal somatotopy for the leg, but not for the foot in all investigated BAs, with large inter-subject variability. We found only minor differences between the properties of the three investigated BAs, suggesting that S1 maps for the lower limbs differ from those described for the hand. We also describe greater extent/strength of S1 activation for the big toe representation (compared to the other mapped representations) within all BAs, suggesting a possible homology between the first digit of upper and lower extremity in humans, and report different patterns of selectivity in the foot representations (i.e. lower selectivity) compared to the other leg representations (i.e. greater selectivity). These data provide a detailed description of human S1 subregions for the foot and leg, highlight the importance of high-resolution mapping studies and of single subject analysis, and indicate potential differences between the lower and the upper limb.
000231975 6531_ $$aCIBM-AIT
000231975 6531_ $$a7 T fMRI
000231975 6531_ $$aBrodmann areas 3b-1–2
000231975 6531_ $$alower limb representation
000231975 6531_ $$aprimary somatosensory cortex
000231975 6531_ $$asomatotopy
000231975 700__ $$aAkselrod, Michel
000231975 700__ $$aMartuzzi, Roberto
000231975 700__ $$aSerino, Andrea
000231975 700__ $$0243732$$g176249$$avan der Zwaag, Wietske
000231975 700__ $$aGassert, Roger
000231975 700__ $$0240593$$g165806$$aBlanke, Olaf
000231975 773__ $$j159$$tNeuroImage$$q473-487
000231975 909C0 $$xU11025$$0252325$$pLNCO
000231975 909C0 $$pCIBM$$xU12623$$0252477
000231975 909C0 $$xU12599$$0252517$$pCNP
000231975 909CO $$pSB$$pSV$$particle$$ooai:infoscience.tind.io:231975
000231975 917Z8 $$x161735
000231975 917Z8 $$x148230
000231975 937__ $$aEPFL-ARTICLE-231975
000231975 973__ $$rREVIEWED$$sPUBLISHED$$aEPFL
000231975 980__ $$aARTICLE