Neural Control of Locomotion in Marine Invertebrates

Richard Satterlie

Frank Hawkins Kenan Professor of Marine Biology, UNCW

Cubomedusan Jellyfish Carybdea marsupialis

Clione limacina Education/Employment Pteropod Mollusc Hydromedusan BS Sonoma State University (California), 1973 Jellyfish Polyorchis penicillatus PhD University of California, Santa Barbara, 1978 Lucifer Yellow fill of the swim motor neurons in the inner nerve ring of the hydromedusa Polyorchis. Only a single neuron was PostDoc University of Alberta (Canada), 1978-1980 filled with the dye, but all neurons are connected by gap junctions which allow passage of the Lucifer Yellow dye. The neurons are Left – Normal, non-feeding posture. Right – Following ballistic Asst. Prof. Arizona State University, 1980-1985 ~25µm at their widest diameters. eversion of buccal cones and capture of prey (shelled pteropod) Assoc. Prof Arizona State University, 1985-1991 Professor Arizona State University, 1991-2004

Awards and Honors Serotonin Immunoreacivity in the cerebral ganglia. Awards and Honors Each ganglion is ~300µm in diameter FMRFamide (neuroactive peptide) immunoreactivity surrounding a radial canal of the hydromedusa Proboscidactyla. The nerve cell Grass Foundation Fellowship in Neurobiology bodies are ~7µm. Neural Control of Locomotory Speed In the (Marine Biological Laboratory, Woods Hole) 1978 Pteropod Mollusc, Clione limacina (Projects – available for grad/undergrad participation) Izaak Walton Killam Memorial Post-Doctoral Scholarship (University of Alberta) 1979-80 Comparative Investigation of 1. Role of a serotonergic arousal system in regulating Swim Control in Jellyfish locomotory speed Dean’s Distinguished Teaching Award, ASU, 1990 (Projects—available for grad/undergrad participation) 2. Neural control of a ballistic startle response Outstanding Professor Award Top – low power electron micrograph of the striated swim muscle Cubomedusae 3. Mechanosensory inputs that trigger swim ASU Golden Key National Honor Society, 1990 of the hydromedusa Polyorchis. Bottom – higher magnification of acceleration Carboxyfluroescein fills of the pair of “whole body withdrawal” the junction between two of the muscle cells showing a pair of 1. Role of the “Diffuse Nerve Net” in modulation of neurons – cell bodies are the bright circles in the pleural ganglia. Distinguished Alumni Award desmosomes surrounding a gap junction. swimming activity in cubomedusae 4. Role of postinhibitory rebound in swim These neurons control protective withdrawal of the body. Cerebral acceleration in pattern generator swim ganglia are to the top, intestinal ganglia at bottom center, pedal Sonoma State University, 1992 2. Organization of the nerve ring (ultrastructure and interneurons ganglia bottom (lateral to the intestinals) physiology) Fulbright Scholar 5. Serotonin-triggered second messenger systems in 3. Feeding-related modulation of swim activity pattern generator interneurons and their roles in University of St. Andrews, Scotland, 1994 4. Protective “crumpling” and its inhibition of swim swim acceleration Parents Association Professor, ASU, 1994-96 6. Role of wing dorsoventral muscles in regulating activity wing stiffness during swim acceleration Guggenheim Fellow, 2002-03 5. Vision in cubomedusae (morphology, 7. Buccal cone ultrastructure ultrastructure, and physiology) 8. Role of the pleural asymmetric white cell in 6. Physiology and biomechanics of turning behavior reproductive behavior Service (current) 7. Modeling of swim pacemaker interactions 9. Synapse identification in wings (ultrastructure and immunohistochemistry) Immunohistochemical stain of wing dorsoventral muscles. The 8. Nervous system morphology through the life cycle dark bands are swim muscle bundles. The dorsoventral muscles run Editorial Board, Integrative and Comparative Biology Top – One of two complex eyes in the rhopalium (sensory club) of into and out of the plane of the poster, and branch as they reach the cubomedusa Carybdea. Cubomedusae have four of these Scyphomedusae each surface epithelium of the wing. The swim muscle bands are sensory clubs, which also contain swim pacemakers. Bottom, left – ~80µm wide. Program Officer, Division of Neurobiology Section through a rhopalium showing the two complex eyes and 1. Dual innervation of swim muscle and the role of Society for Integrative and Comparative Biology two of the four ocelli (less complex photoreceptor structures). the “Diffuse Nerve Net” in swim modulation Bottom, right – Section through one of the ocelli. Some researchers claim that cubomedusae can form images with the 2. Eyes of scyphomedusae and photoreception complex eyes. This is an active area of scientific debate and research. 3. Physiology and biomechanics of turning behavior 4. Modeling of swim pacemaker interactions 5. Nervous system morphology through the life cycle Hydromedusae 1. Morphology of conducting systems and their roles in controlling and regulating swimming

Sensorin immunoreactivity in the central nervous system of Clione. Top trace – intracellular recording of a pattern generator Double label immunohistochemical preparation from the cubomedusa All Groups (including Anthozoans) Sensorin marks primary mechanoreceptor neurons. This is a stereo interneuron. Each spike triggers a dorsal swim contraction of the Tripedalia cystophora. The red stain (actin antibody) shows the pair. If you defocus until you see three images, concentrate on wings. Bottom trace – extracellular recording from the wing nerve. striated swim muscle that lines the inside of the bell. Note the Evolution of gap junctions – presence in the Hydrozoa the center one of the three, and you may see a single At the arrow, a swim acceleration occurs. Note the increased striations. The green stain shows neurons of the subumbrellar motor and absence in the Scyphozoa, Cubozoa, and frequency of interneuron firing, baseline depolarization, and in the nerve net (tubulin antibody). The large swellings on the green 3-D image. Anthozoa (molecular biology project) wing nerve, recruitment of large spike elements. neurons are ~15µm.