Neuronal Correlates of the Simulation, Execution, and Perception of Limb Movements

Abstract

Humans and animals can control only what they can sense. We therefore cannot precisely control voluntary movements that require elaborate motor control of our body parts unless we can perceive those movements. The neuronal correlates of the mental representation of the “body image”—our perception of the size, shape, movements, and relative configuration of our body parts (Head and Holms 1911)—have long been uncertain. Because brain damage often causes one’s body image to be distorted (Berlucchi and Aglioti 1997; Berti et al. 2005; Sellal et al. 1996), the body image represented as neuronal activity in our brain must be the result of neuronal computation and the integration of multisensory information (somatosensory and visual) about our body (Graziano and Gross 1998). Because people can sense and move body parts without the aid of vision, however, the body image must largely depend on somatic input. Recent neuroimaging techniques such as functional magnetic resonance imaging (fMRI) allow us to investigate the neuronal representations that are related to various types of our body image by measuring brain activity while people perceive limb movements (Naito 2004) or experience changing body configurations (Ehrsson et al. 2005). This chapter introduces neuronal representations underlying the somatic perception of various types of limb movements (particularly hand movements) and discusses how people perceive these movements and how this perception is related to the control of those movements.