Amputees often feel 'phantom' sensations emanating from their missing limb (for a review, see Giummarra et al 2007). This entry discusses the role of action and perception in the constitution of these physically absent yet phenomenally present body parts. I urge the view that phantoms are to some extent enactive – they are constituted by active perceptual engagement with the world (see e.g. Noë 2004).
Impressed by the way in which a blind man localised sensations at the tip of his cane, Head and Homes (1911) hypothesised that his brain must update its representation of bodily posture on the fly and treat the cane as part of his arm. It turns out that they were correct; neural representations of limb locations are highly adaptable and continually modified by vision, touch, and kinaesthesia. Experiments on macaques reveal that while using a rake to retrieve food, the receptive field of neurons in somatosensory cortex – the location of the brain's inner model of the body – extends beyond the boundary of the monkeys' arm to incorporate the area occupied by the rake (Iriki, Tanaka & Iwamura1996).