Everyday experience has taught animals and humans alike that activation
of certain types of cutaneous and deep tissue sensory receptors not only
evokes sensations but induces a great variety of motor and autonomic
responses, some of them being very welcome, others not at all. As regards
the autonomic responses, which are the topic of this review, examples of
the welcome type include the vasodilation of an ice-cold hand as a con￾sequence of stimulating its warmth receptors when exposing the hand to
an open fire place. On the other hand, unwelcome autonomic effects of
somatosensory activity include, amongst many more harmless examples,
the severe symptoms of circulatory failure, sweating, nausea, vomiting
etc. as a consequence of excruciating visceral pain.