Visual parameters of looming stimuli that trigger the escape of a crab and neuronal correlates.

OLIVA, DAMIÁN; MEDAN, VIOLETA; TOMSIC, DANIEL

Vancouver

Congreso; 8th International Society for Neuroethology Meeting; 2007

International Society for Neuroethology

An object that approaches on a collision course (looming stimuli) provokes in Chasmagnathus a strong and highly directional escape response. Recently, wehave shown that this response can be reliably elicited and precisely measured in the laboratory. Moreover, by performing in vivo intracellular recordings from theoptic lobe, we found two classes of lobula giant neurons that appear to play a key role in the behavioral response to looming stimuli (Oliva et al. 2007). Toinvestigate what features of the image expansion generated during the object approach are the ones considered by the crab to initiate the escape, wechallenged the animals with a set of different looming stimuli that varied either in their size or speed of approach. In addition, we evaluated the performance ofthe two classes of lobula giant neurons called MLG1 and MLG2 (see poster 32 by Medan et al.) to the same stimuli.