Central pattern generators (CPGs) are neuronal circuits that underlie rhythmic movements including breathing and chewing. CPGs are capable of producing complex, rhythmic outputs in the absence of input signals, but are also capable of modifying the pattern in response to sensory feedback. Therefore, investigating the interplay between sensory-regulated and intrinsically controlled output is crucial in understanding disorders of rhythmic movement. The crab Cancer borealis stomatogastric nervous system includes two feeding-related CPGs and is an ideal model organism to study their function. The gastric mill CPG is responsible for chewing food within the foregut via gastric mill muscles, one of which, gm1, is directly below the shell (carapace). We measure contraction of the gm1 muscle when active during gastric mill rhythms using photoplethysmography (PPG) noninvasively in vivo. In response to environmental changes in feeding (different food textures), we observe how sensory feedback changes the speed, strength, and duration of the gastric mill rhythm. We aimed to answer the questions: (1) what causes the gastric mill rhythm to turn on? (2) Is there a difference in frequency and amplitude of the gastric mill rhythm when we feed soft food (squid) versus crunchy food (shrimp)? Establishing a difference in the gastric mill’s behavior between different foods helps elucidate the purposes for different patterns of the rhythm.
Author(s): Abby Smith, Biology and Spanish Major
Sarah Johnson, Microbiology Major
Advisor(s): Dawn Blitz, Department of Biology
You must be logged in to post a comment.