The spinomesencephalic tract has been described travelling with the spinotectal tract to the periacqueductal grey matter and superior colliculus of the midbrain. The spinohypothalamic pathway is a very recently described route which does not synapse in the reticular formation. It carries information of emotional significance from the skin, lips, sex organs, gastrointestinal tract, intracranial blood vessel tongue and cornea directly to the hypothalamus. Clearly there is one pathway that is concerned with a discriminative analysis of pain, but many others that concern our reactions to it, and feelings about it. Unfortunately there is no discrete centre where pain is recognised.
Pain is so important to survival that almost the whole brain is involved.
Pain involves cognition, emotion, and behaviour. Therefore it is not surprising that PET scan data obtained during painful stimulation indicates activity in the following cortical areas . Brodmann's tissue classification follows in brackets. References Boivie J, Central pain syndromes. An Updated Review, IASP Press, Seattle, p.23-29.