Anaesthetisation of prefrontal cortex and response to noxious stimulation

Abstract

REPORTS indicate that responses to pain may be modified by damage to the frontal lobes (see refs 1 and 2). Nevertheless, neither the nature of the change nor the degree to which any effect of damage is localised anatomically has been firmly established. I have systematically examined the function of the prefrontal cortex in response to an aversive stimulus in the rat. Small quantities of a short-acting anaesthetic, procaine hydrochloride, were injected to block directly the neural function of specific areas within the prefrontal cortex. The prefrontal cortex in the rat occupies both a lateral region, the dorsal bank of the rhinal sulcus, and a medial region, the pregenual medial wall of the hemisphere³. In the rat, the prefrontal cortex is involved in brain-stimulation reward⁴. I suggest that, in addition, the prefrontal cortex acts to limit the response to painful stimulation, and that this anti-nociceptive function is localised in or near the sulcal region.