A probabilistic atlas of finger dominance in the primary somatosensory cortex
George C. O’Neill,
Ayan Sengupta,
Michael Asghar,
Eleanor L. Barratt,
Julien Besle,
Denis Schluppeck,
Susan T. Francis,
Rosa M. Sanchez Panchuelo
Affiliations
George C. O’Neill
Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK; Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, London, UK
Ayan Sengupta
Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK; Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Department of Psychology, Royal Holloway, University of London, Egham, UK
Michael Asghar
Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
Eleanor L. Barratt
Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
Julien Besle
Department of Psychology, American University of Beirut, Beirut, Lebanon
Denis Schluppeck
School of Psychology, University of Nottingham, Nottingham, UK
Susan T. Francis
Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK; NIHR Nottingham Biomedical Research Centre, University of Nottingham, Nottingham, UK
Rosa M. Sanchez Panchuelo
Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK; Corresponding author. Sir Peter Mansfield Imaging Centre, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom.
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). 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. 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.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 validated using a leave-one-out cross validation procedure. Anatomical variance across the somatotopic map is also assessed to investigate whether the functional variability across subjects is coupled to structural differences. 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. The atlas and constituent subject maps are available online for use as a reference in future neuroimaging studies.
