Somatosensory plasticity at 7T: neurochemicals, maps, and perception
The ordered topography of primary somatosensory cortex (SI) has long served as a model system for studies of both cortical organisation and reorganisation. To date, studies of the fine-grain detail of such cortical maps have remained largely the domain of electrophysiologists working with animal models. However, with recent advances in the spatial resolution of fMRI, afforded by the advent of 7 tesla systems, it is now feasible to resolve the detailed functional architecture of SI at the level of individual human participants. Here I present the results of a series of studies focused on single-subject mapping of the cortical representations of the digits (fingers) in SI. Specifically, I will outline the mapping approach applied and the observed inter-subject variability of these maps in SI, before going on to discuss evidence for extremely short-term experience-dependent plasticity in these representations. Finally, I will aim to put these maps into context, exploring the relationship of cortical somatotopy with both MRS-derived measures of neurochemicals, and perceptual measures of tactile function.