Phantom limbs are traditionally conceptualized as the phenomenal persistenc
e of a body part after deafferentation, Previous clinical observations of s
ubjects with phantoms of congenitally absent limbs are not compatible with
this view, but, in the absence of experimental work, the neural basis of su
ch "aplasic phantoms" has remained enigmatic. In this paper, we report a se
ries of behavioral, imaging, and neurophysiological experiments with a univ
ersity-educated woman born without forearms and legs, who experiences vivid
phantom sensations of all four limbs. Visuokinesthetic integration of tach
istoscopically presented drawings of hands and feet indicated an intact som
atic representation of these body parts. Functional magnetic resonance imag
ing of phantom hand movements showed no activation of primary sensorimotor
areas, but of premotor and parietal cortex bilaterally. Movements of the ex
isting upper arms produced activation expanding into the hand territories d
eprived of afferences and efferences, Transcranial magnetic stimulation of
the sensorimotor cortex consistently elicited phantom sensations in the con
tralateral fingers and hand. In addition, premotor and parietal stimulation
evoked similar phantom sensations, albeit in the absence of motor evoked p
otentials in the stump. These data indicate that body parts that have never
been physically developed can be represented in sensory and motor cortical
areas. Both genetic and epigenetic factors, such as the habitual observati
on of other people moving their limbs, may contribute to the conscious expe
rience of aplasic phantoms.