On the significance of viscerosomatic convergence

Abstract

Viscerosomatic convergence is a surprisingly common inducible feature of the response properties of neurons throughout the central nervous system. It indicates an extensive potential overlap between neuronal domains that process interoceptive information and those that process exteroceptive and proprioceptive information. This potential for overlap suggests that responses of individual neurons serve different functions at different times depending on the current pattern of activity in other neurons throughout the nervous system. Within such a dynamic scheme, skin and skeletal muscle have access to interoceptive control mechanisms and take variable advantage of that access for different purposes, for example, for shunting blood supply to tissues that need it. Similarly, viscera have access to exteroceptive control mechanisms and use them flexibly as needed. One important use would be to employ the exteroceptive domain's efficient protective mechanisms when a viscus is under threat. Visceral and referred pain would thus be byproducts of this opportunistic tactic.