This is an open book, open notes exam. You may take up to 24 hours to complete this test. Each question is worth 20 points. Please put your name on all sheets. Under no circumstances should your answers exceed the space given.
Nematodes are the most ubiquitous phylum in the animal kingdom, found on land, sea and air.
Their CNS is well defined with an assemblage of sensory, motor, and interneurons typical of other Metazoans. Their most obvious behavior is simple wriggling, consisting of alternating dorsal and ventral flexions which are mediated by dorsal and ventral longitudinal muscles that run the length of the body. Each muscle is innervated by a single excitatory motoneuron. Describe and draw a neuronal circuit underlying this simple behavior. Include the neurons that comprise the central pattern generator and make sure your circuit produces alternating contractions of the dorsal and ventral musculature.