Meeting Abstract

66.1  Saturday, Jan. 5  Chemosensory and Mechanosensory Mediation of Inter-sucker Coordination in Octopus bimaculoides NAIR, S.*; BAROCAS, J.; HADJISOLOMOU, S.; GRASSO, F.W.; Brooklyn College, City University of New York; Brooklyn College, City University of New York; Brooklyn College, City University of New York; Brooklyn College, City University of New York savithrinair@yahoo.com

Coleoid cephalopods possess suckers on their arms and tentacles but Octopus suckers are distinguished by their extrinsic muscles which permit the animal to move them independently of arm motions. The neuroanatomical sensory-motor structures (ganglia, nerve roots and tracts) of the suckers and arms that support arm-sucker coordination have been mapped, but the information that is shared between them has not been thoroughly explored. We hypothesized that mechanical and chemical stimulation of a single sucker would be communicated to adjacent suckers. We found significant responses (movements made after stimulus application) to both types of stimuli in neighboring suckers. This relationship diminished with distance from the stimulated sucker. We also hypothesized that different chemical stimuli and different mechanical loads would elicit different types of reactions from the nearby suckers. Different types of chemical stimuli (low or high pH, octopus extract and artificial sea water, a neutral stimulus,) suspended in agar elicited differential reactions from neighboring suckers when placed in contact with a focal sucker. Different mechanical loads also produced differential responses in that recruitment of responses from suckers neighboring the stimulated sucker increased with load. We found a tendency for suckers proximal and distal to the stimulated sucker to respond differently to a given level of stimulation (chemical or mechanical). Our results demonstrate new functional properties of the sensory-motor neural networks that underlie arm-sucker coordination in Octopus.