Due to the fine architecture of the cortical representation of the digits of the hand in the post-central gyrus ( Geyer et al., 2000), somatotopic mapping is more challenging than retinotopic and tonotopic mapping, in terms of both the spatial resolution of cortical maps and the statistical power ( Francis et al., 2000 Gelnar et al., 1998 Huang and Sereno, 2007 Kurth et al., 2000 Nelson and Chen, 2008 Overduin and Servos, 2004 Weibull et al., 2008). It has revealed the retinotopic organization of the visual cortex ( DeYoe et al., 1996 Engel, 1997 Sereno et al., 1995 Wandell et al., 2007), tonotopic organization in the auditory cortex ( Da Costa et al., 2011 Formisano et al., 2003 Moerel et al., 2018, 2012 Saenz and Langers, 2014) and the cortical representation of body parts ( Akselrod et al., 2017 Sanchez Panchuelo et al., 2018), particularly the digits of the hand ( Besle et al., 2013 Sanchez Panchuelo et al., 2010 Schweisfurth et al., 2015, 2014 Stringer et al., 2011 van der Zwaag et al., 2015) in the primary somatosensory cortex (S1). The atlas and constituent subject maps are available online for use as a reference in future neuroimaging studies.įunctional magnetic resonance imaging (fMRI) has proved to be a valuable tool for the non-invasive in-vivo study of orderly topographic organization of different cortical areas in humans. This probabilistic atlas quantifies the variability in digit representations in healthy subjects, finding some quantifiable separability between digits 2, 3 and 4, a complex overlapping relationship between digits 1 and 2, and little agreement of digit 5 across subjects.

Anatomical variance across the somatotopic map is also assessed to investigate whether the functional variability across subjects is coupled to structural differences. The atlas is validated using a leave-one-out cross validation procedure. Metrics quantify the likelihood of a given position being assigned to a digit (full probability map) and the most probable digit for a given spatial location (maximum probability map). The atlas is generated in both volume and surface standardised spaces from somatotopic maps obtained by delivering vibrotactile stimulation to each distal phalangeal digit using a travelling wave paradigm.

Here we generate a probabilistic atlas of the contralateral SI representations of the digits of both the left and right hand in a group of 22 right-handed individuals. With the advent of ultra-high field (7T), high spatial resolution functional MRI (fMRI) has allowed the differentiation of the cortical representations of each of the digits at an individual-subject level in human primary somatosensory cortex (S1).

Carman scan 1 software cardinality