Insights from a formidable companion, the crab Neohelice granulata. CONFERENCIA

JULIETA SZTARKER

Brisbane

Congreso; ICN 2018; 2018

ISN

Neohelice granulata is a highly visual semi-terrestrial crab that displays a rich collection of behaviors, including a variety of escape responses, attacks to smaller crabs and diverse conspecific interactions. Using a combination of techniques such as lab and field behavioral analyses, intracellular recordings, calcium imaging techniques and histology we are advancing our understanding of the neural bases of such behaviors. So far, we have focused our research in exploring giant tangential neurons from the lobula (LG) the activity of which greatly correlates with different attributes of an escape response elicited by a visual danger stimuli and with the behavioral changes induced by learning. Interestingly, two classes of LG, MLG1 and MLG2 respond to approaching stimuli with a profile of response that closely follow the dynamic of expansion of the looming stimuli. MLG1 is part of an ensemble of 16 elements distributed uniformly over the whole lateromedial lobula axis. These neurons have large principal neurites that are easily identifiable in unstained brains. I will show new ultraestructural data that illustrate the connectivity patterns of MLG1. I will also present data from behavioral experiments aimed at exploring optomotor responses in two crab species belonging to two different families (Neohelice granulata and Uca uruguayensis), which shade light on the underlying circuit that commands this behavior. In addition, I will talk about other nervous structures identified in the optic lobes, the function and morphology of which are just starting to become clear.