Emerging principles in functional representations of touch

The somatosensory system is fundamental to the formation and maintenance of coherent representations of the human body. Traditional concepts of somatosensation have been shaped by the principles of somatotopic and hierarchical organisation of primary somatosensory and motor cortices. However, emerging research has shown that perceptual and neural representations of touch are not fully captured by these principles. In this Review, we critically discuss how newer empirical research has expanded the understanding of touch and body representations. We first consider the role of higher-level categorical information about the body and its parts and the standard configuration of the body. We then discuss empirical evidence showing that functional representations of touch can complement and integrate across topographic organisation. Finally, we review how the processing of touch is influenced by the source of the touch (another person or an object), and how the identity of the toucher shapes responses.