Knowing that you have pain requires something
else that occurs after the neural patterns that
correspond to the substrate of pain – the
nociceptive signals – are displayed in the
appropriate areas of the brain stem, thalamus,
and cerebral cortex and generate an image of
pain, a feeling of pain.
(Damasio, 1999, p. 73)This next stage is also in the brain. It is ‘the neu-
ral pattern of you knowing, which is just another
name for consciousness’ (p. 73). This means that
the necessary neural correlates for pain are to
have both the activity in the pain system, and the
neural pattern of self – and both are not just cor-
relates, but causes.
Saying that feeling pain depends on knowing
you are in pain allows Damasio to distinguish
between self-willed actions and automatic
reactions, such as removing your hand from
the hotplate before you even felt the pain – in
this case, there is no pain before the action,
only afterwards once your knowledge catches
up. But Damasio undermines his own argument
by saying that even the first pattern alone
‘generate[s] an image of pain, a feeling of pain’
(Damasio, 1999, p. 73). He claims that the feel-
ing of pain depends on knowing one is in pain,
but at the same time he still relies on the more
traditional assumption that nociceptive signals
alone can be sufficient. Notice also that the neu-
ral patterns are ‘displayed’, and that the ‘feeling‘the neural pattern of
you knowing, which is
just another name for
consciousness’
(Damasio, 1999, p. 73)
FIGURE 4.8 • The somatosensory homunculus.
In the somatosensory cortex each
part of the body is represented
in a different area. When input
from one part is missing, the input
from other parts can invade that
area. According to Ramachandran,
this can explain why amputees
sometimes feel real cold on their
face as cold in their phantom
fingers, or sexual stimulation as a
touch on their phantom foot.that the limb is still there. Accordingly, many surgeons
have operated on stumps, performed further amputa-
tions, cut the sensory nerves, and even operated on the
spinal cord, often without stopping the pain.
A completely different approach was taken by Ramachan-
dran (Ramachandran and Blakeslee, 1998). He reasoned
that when we clench our fist, feedback from the hand tells
us when to stop, but with no hand there is no such feed-
back and motor signals to clench keep on going, causing
the pain. He positioned a mirror in front of a patient so
that he could see his normal hand reflected where his
phantom should be. When the patient moved his normal
hand, he saw what appeared to be the phantom moving,
thus providing the necessary feedback. In about half Ram-
achandran’s cases the phantom seemed to move and the
pain eased. In one case, after practising with the mirror, a
painful phantom arm that had lasted ten years completely
disappeared. Ramachandran claims to have been the first
to ‘amputate’ a phantom limb. other methods have since
used sensory and motor retraining, brain stimulation, and
virtual reality (Lenggenhager et al., 2014).
the reason why phantoms can be so persistent is that
they are part of our body schema. this ‘phantom body’ is
the brain’s simulation of our bodily form that uses touch,
vision, and other inputs to keep an updated model of our
posture, position, and actions, and is essential to coordi-
nate movement. the basic form of the body schema is
innate (melzack, 1989), so that if a limb is lost its ghostly
version remains.