Optical flow-based characterization of serotonergic modulation of crayfish hindgut motility

Peristalsis is a series of gastrointestinal (GI) contractions carrying food through the digestive tract. Due to its major role in maintaining homeostasis, several drivers have evolved for its smooth functioning: from motor input from the central nervous system (CNS) or enteric nervous system (ENS) lining the gut. Recent studies have shed light on the shared neurochemistry and structure between these, which have often led to comorbid GI and neurological disorders while dysfunctional. To fully understand this interaction between ENS and CNS, it is crucial to study a shared signaling pathway. Receptors for Serotonin, a common neurotransmitter, were previously observed to be embedded along the lining of the gut, suggesting its role in muscular contraction. However, it is not clear to what degree peristalsis is driven by local Serotonin concentration as compared to the CNS input. To explore this relationship further, we study a simple crayfish model and capture its hindgut motility under denervation and serotonergic excitation. Using optical flow as a motion detection tool, we identify and characterize patterns of gut motility. We study whether adding Serotonin could compensate for the lack of CNS input and how these motility patterns differ from the typical gut motion.