Central pattern generators (CPGs) are circuits that generate rhythmic motor outputs which govern rhythmic behaviors. CPG core rhythmic activity is based on intrinsic and synaptic properties but can be altered by neuromodulators (Bucher et al., 2015). Neuromodulators can act on multiple levels: directly on the CPG circuit or indirectly modulating the circuit by acting on descending modulatory projection neurons (Marder and Bucher, 2006). There is much less known about indirect modulatory actions.

 Here, I am examining a novel indirect pathway: sensory neurons that project through the paired labral nerves within the crustacean stomatogastric nervous system. The aim of this research is to trace the anatomical pathways of the labral nerve neurons and locate their cell bodies. Stimulation and recording from these nerves will then be used to further determine their actions, and the stimuli that activates these neurons.

• Stimulate and record from the crustacean labral nerves

• Identify the stimulus to which the labral neurons respond

• Identify how a signal from the labral neurons affects the gastric mill rhythm