Langley initially expected to find afferent cell bodies in autonomic ganglia, with projections to other ganglia. He believed that activation of these “autonomic afferents” should lead to purely autonomic responses. However Langley’s own careful work demonstrated that there were no such neurons.
The fundamentally important point is that integrative processes responsible for the organization of visceral function occur principally within the central nervous system (brain and/or spinal cord). Both somatic and visceral afferents result in complex, brain mediated, responses that include somatic and visceral function. Autonomic motor activity can be generated by both somatic and visceral inputs to the CNS, and visceral inputs to the CNS initiate responses that are both somatic and autonomic.
Natural bodily functioning does not include “purely autonomic” or “purely somatic” responses, just as it does not include ‘purely sympathetic” or “purely parasympathetic” responses.
Bill Blessing and Ian Gibbins (2008), Scholarpedia, 3(7):2787. revision #46085 [link to/cite this article] Curator: Dr. Bill Blessing, Centre for Neuroscience, Flinders University, Adelaide, AUSTRALIA