Are feature detection and optic flow analysis segregated in crabs?

JULIETA SZTARKER

Montevideo

Congreso; XII International Congress of Neuroethology; 2016

ISN

Visually-guided prey capture behaviors, alike predator avoidance behaviors, require analyzing the retinal motion generated by the external moving target (prey or predator), as well as the panoramic optic flow self-generated during the chasing or escaping performance. While the first is required to classify, pinpoint the location and tracking the potential prey or predator, the second is needed for an accurate control of the course of these actions. In insects, neurons involved in processing object motion have been described in the lobula (third optic neuropil). On the other hand, neurons involved in optic flow analysis have been described in the lobula plate (a tectum like neuropil).The crab Neohelice granulata offers methodological advantages for the study of visual information processing, including the possibility of recording intracellularly the response to visual stimuli of neurons in the intact animal. After years of recordings, we have shown that giant neurons from the lobula are tuned to object motion, but not to flow field motion. Crabs do respond to optic flow: they display strong compensatory eye movements to panoramic displayment (optomotor response) but where this information is processed is unknown. Recently, the presence of a neuropil alike the lobula plate was identified in crabs. Here we describe the characteristics of this neuropil, its neuronal components and preliminary results on the behavioral consequence of lesion experiments. Our results support the idea that, in the crab, the information of object motion and of optic flow field are segregated and processed in the lobula and lobula plate respectively.