LOI, Poh Kheng/*; TUBLITZ, Nathan/J; GASTON, MIchelle/R; Institute of Neuroscience, University of Oregon; Institute of Neuroscience, University of Oregon; Institute of Neuroscience, University of Oregon: Neural control of body patterning in the European cuttlefish Sepia officinalis. P.K. Loi* , N.J. Tublitz & M.R. Gaston. Institute of Neuroscience, University of Oregon.

Unshelled cephalopods exhibit a wide range of body patterns used for camouflage, inter- and intra-species communication. Body patterns in cephalopods are highly plastic; they are generated in less than a second and can be held for a fraction of a second or for hours. These body patterns are formed by a unique chromatophore system under direct neuromuscular control. The goal of our lab is to fully elucidate the mechanisms underlying body patterning behavior in cephalopods, with a primary emphasis on the European cuttlefish Sepia officinalis . Our studies on chromatophore activity show that several neurotransmitters control chromatophore expansion. Glutamate mediates rapid chromatophore expansion where as FMRFamide-related peptides (FaRPs) are responsible for a much slower rate of chromatophore expansion. Immunocytochemical studies confirm the presence of both types of transmitters in the neurons in the anterior(ACL) and posterior chromatophore lobes (PCL) and also in the peripheral terminals of chromatophore motoneurons. Some of these neurons were immunopositive for both glutatmate and FaRPs. Molecular studies in the cuttlefish revealed 2 FaRPs encoding genes in Sepia. In situ experiments showed that one of the FaRPs encoding gene is expressed in the ACL and PCL. Reconstruction studies using nerve backfilling and electrical stimulation suggest the possibility of a topographic mapping within the PCL of the chromatophore motoneurons.Experiments with other cephalopods reveal that the glutamate/ FaRPs regulation of chromatophore activity is widespread among the cephalopods. Although all species appear to have the glutamate system, a functional FaRP control system is limited to cuttlefish and octopi