Table 1.

Indications of learned gut behavior and the neurophysiological proxis (see text for detailed discussion)

Function	Stimulus	Induced, “learned” gut behavior	Putative neural correlate
Motility	Muscle response induced by: • Repetitive distension (<10 sec) • Repetitive distortion or chemical stimulation of mucosa • Muscle distension after mucosal distortion (≥2 min) • Distension of adjacent regions • Conditoned distension (repetitive stretch of 1.5g→3g→1.5g) • Repetitive gastric step-wise distension (5-20 mmHg) • Stress • High fat diet	• Attenuated peristaltic reflex • Attenuated peristaltic reflex • Enhanced peristaltic reflex (cross-sensitization) • Enhanced relaxation • Enhanced intestinal contraction after conditioning • Enhanced adaptive relaxation • Increased colonic motility • Increased gastric emptying	• Synaptic depression in sensory circuits • Synaptic depression in sensory circuits • Synaptic facilitation in sensory circuits • ? • Sustained postsynaptic excitation (LTP), hyperexcitability of sensory neurons • Synaptic facilitation in sensorimotor circuits • LTP and hyperexcitability of sensory neurons • Synaptic facilitation
ENS activity	• Acute inflammatory insult • Post-inflammatory conditions	• Decreased propulsive motility “Attention deficit disorder” • Decreased colonic propulsion “Attention deficit disorder”	• Synaptic facilitation, hyperexcitability of sensory neurons, • Hyperexcitability of sensory neurons and synaptic facilitation remains
Motility disorders	• Postinfectious irritable bowel syndrome • Postinfectious functional dyspepsia	• Dysmotility • Dysmotility	• Postsynaptic sensitization and desensitization • Hyporesponsiveness to synaptic activation