Neurological disorders leading to mechanical dysfunction of organs: emergent behavior of a neuromechanical dynamical system

An understanding of how neurological disorders lead to mechanical dysfunction of organs remains an open problem. For example, opioid-induced gastrointestinal (GI) motility disorder is known to be of neurological origin but with scarce understanding of how mechanical dysfunction emerges. Organ-scale neuromechanical models are needed to answer such questions. Using esophagus as a model problem, we demonstrate how emergent behavior of a neuromechanical dynamical system can help resolve longstanding questions. Specifically, we focus on repetitive antegrade contractions (RACs) pattern in the esophagus that emerges in response to sustained volumetric distension. Any deviations from the baseline RACs pattern indicates esophageal motility disorder. In this study, we seek to settle an ongoing debate on the emergence of RACs by developing a new empirically guided neuromechanical model. The neural circuitry is constructed as a chain of unidirectionally coupled relaxation oscillators, receiving excitatory signals from stretch receptors along the esophageal body. We successfully reproduce normal and abnormal esophageal response to distension. This work potentially provides a template to interrogate neurologically driven mechanophysiological pathologies of organs.