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Figure 1 | BMC Physiology

Figure 1

From: Inference of mechanical states of intestinal motor activity using hidden Markov models

Figure 1

An overview of data acquisition, and how mechanical muscle states relate to the data. (a) A schematic of the experimental setup. A section of rabbit colon is kept alive in an organ bath and simultaneous intraluminal pressure (fibre-optic catheter, sensors spaced at 10 mm) and diameter (camcorder) are recorded during peristaltic movements. (b) from these recordings a diameter (magenta) and pressure (green) spatiotemporal map is created. (c) at any location within the diameter-pressure map we can plot the values of pressure (green) and diameter (magenta). In this example the values are taken from the 5s white line on the diameter-pressure map. (d) Plotting the relation between pressure and diameter in (c) is then displayed as an orbit plot. From the orbit plot the mechanical states of the muscle can be determined. In the example shown here 3 different mechanical states can been observed during the selected 5s period. The first mechanical state (blue–aqua section of the line) shows a decrease in diameter with no change in pressure (isotonic contraction; itc). In the next mechanical state (aqua–yellow) the pressure begins to increase with a corresponding decease in diameter (auxotonic contraction; atc). In the final mechanical state (yellow–red) the pressure drops with no further change in diameter (occluded isometric relaxation; oimr).

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