Quantifying Patterns of Smooth Muscle Motility in the Gut and Other Organs With New Techniques of Video Spatiotemporal Mapping

Abstract

The uses and limitations of the various techniques of video spatiotemporal mapping based on change in diameter (D-type ST maps), change in longitudinal strain rate (L-type ST maps), change in area strain rate (A-type ST maps), and change in luminous intensity of reflected light (I-maps) are described, along with their use in quantifying motility of the wall of hollow structures of smooth muscle such as the gut. Hence ST-methods for determining the size, speed of propagation and frequency of contraction in the wall of gut compartments of differing geometric configurations are discussed. We also discuss the shortcomings and problems that are inherent in the various methods and the use of techniques to avoid or minimize them. This discussion includes, the inability of D-type ST maps to indicate the site of a contraction that does not reduce the diameter of a gut segment, the manipulation of axis [the line of interest (LOI)] of L-maps to determine the true axis of propagation of a contraction, problems with anterior curvature of gut segments and the use of adjunct image analysis techniques that enhance particular features of the maps.

Embryogenesis of the peristaltic reflex

“…C ). These maps are similar to D‐maps (Lentle & Hulls, ), but the grey level is not directly proportional to the diameter change. The rostro‐caudal axis runs from top to bottom for all maps shown.…”

Optical Ultrastructure of Large Mammalian Hearts Recovers Discordant Alternans by In Silico Data Assimilation

“…In such a perspective, including specialized lighting setups would concur to reduce specular reflection. In particular, a cross-polarized lighting setup may provide the best quality images with the least specular reflection and most detailed textures (Lentle and Hulls, 2018). The appearance of optical ultrastructure further connects the present study with a major and multidisciplinary research effort in high-resolution imaging of large biological tissues (Kuruppu et al, 2021).…”

Methodological considerations in studying digestive system physiology in octopus: limitations, lacunae and lessons learnt

“…The external profile of the digestive tract changes with the progression of contractions and also as the degree of distension of a particular segment is changed by bolus progression. High resolution video recording of the digestive tract followed by automated computer analysis of the apparent diameter enables the generation of "spatiotemporal maps" showing the contractile activity, its magnitude, direction (oroanal or ano-oral) and speed of travel (see Lentle and Hulls, 2018 for review of the method). Spatiotemporal mapping frequently used in mammals to investigate the effects of drugs (e.g., in mouse stomach, Worth et al, 2015) has also been utilised to study motility in the digestive tract of the fish Oncorhynchus mykiss (Brijs et al, 2017a) and Myoxocephalus scorpius (Brijs et al, 2014;Brijs et al, 2017b).…”