Emerging principles in functional representations of touch

The somatosensory system is fundamental to the formation and maintenance of coherent mental representations of the human body. Traditional concepts of somatosensation have been shaped by the principles of somatotopic and hierarchical organization of the primary somatosensory cortex and the motor cortex. 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 our 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 organization. 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. The somatosensory system processes tactile sensations to represent the human body. In this Review, Tamè and Longo discuss updates to the classical principles of somatosensation that reflect emerging patterns and complexities in how touch is represented.