High Resolution Functional Mapping of Primary Motor Cortex & Primary Somatosensory Cortex in Humans at 7T

Robert Trampel¹, Andreas Schfer¹, Robin Martin Heidemann¹, Dimo Ivanov¹, Gabriele Lohmann¹, Stefan Geyer¹, Robert Turner¹

The functional properties of the sensorimotor system have been intensively studied by functional MRI over the last decades. Typical fMRI resolution at field strengths at 3 Tesla and below enables a rough somatotopic mapping, but may not unambiguously differentiate between primary motor cortex (M1) and primary somatosensory cortex (S1). Here, we performed isotropic sub-millimeter fMRI at 7 Tesla, using a paradigm comprising finger tapping, finger movement without touching the finger tips and imagined finger movement. Spatial differences in activation in S1 and M1 could be distinguished, and also signal time courses dependent on the laminar position across M1 cortex were obtained.