Frontiers in Systems Neuroscience Systems Neuroscience

Abstract

neurons may be altered. Indeed, Chiappe et al. (2010) have recently shown that locomotion can alter the velocity tuning of optic flow-processing interneurons in the blowfly. To identify neural mechanisms that may be involved in the loco-motor state modulation of velocity coding of optic flow–process-ing interneurons, we have investigated how a pharmacologically induced state change affects the velocity coding of an identified visual interneuron of the blowfly, the H2 cell. We chose the blow-fly as a model system because its eye movements and optic flow-processing neurons, the lobula plate tangential cells (LPTCs), have been exceptionally well characterized (revs: Hausen, 1993; Krapp and Wicklein, 2008). A characteristic behavior of moving flies is to perform rapid yaw turns, whose velocity is twice as high during flight as during walking (Hateren and Schilstra, 1999; Blaj and van Hateren, 2004). We chose the H2 cell because it supports optomotor responses to yaw rotations, as part of a recurrent network of cells tuned to horizontal motion (Hausen, 1982a,b; Haag and Borst, 2001; Krapp et al., 2001). We induced the state change in the blowfly using the octopamine agonist chlordimeform (CDM). Octopamine is a biogenic amine that plays a significant role in fight-or-flight responses in insects (Roeder, 2005). It is released in high quantities throughout the