The circuitry of the enteric nervous system

Abstract A brief account of the aquisition of knowledge of the enteric nervous system and the ways in which technological developments have contributed to analysis of the reflex circuits is presented. The review concentrates on the motility controlling circuits in the small intestine of the guinea-pig, where much more is known than for any other region or species. In this region, the basic circuit is known. Primary sensory neurons connect monosynaptically to motor neurons, and also make connections via chains of interneurons, which in turn provide outputs to the motor neurons. The ascending excitatory and descending inhibitory reflexes are manifested through these circuits. Sufficient details of the functions and connections of all neuron classes are available to permit activity in the reflex pathways to be realistically simulated in a computer model, which is briefly described.