Neurobiology of visually guided prey and predator behaviors in crabs

DANIEL TOMSIC

Montevideo

Congreso; XII International Congress of Neuroethology; 2016

International Society for Neuroethology

In nearly all active moving animals vision constitutes the most important source of external information for organizing the behavior. Visual abilities likely originated to avoid obstacles during navigation and to detect and anticipate predator assaults. In order to escape from a predator, animals need to recognize the menace, localize it in space and determine the trajectory of attack. They also usually survey the environment in search of potential shelters. Additionally, they may count on memorized experiences about similar events. With all this information plus the time conferred by distant visual detection, animals make decision on the appropriate strategy to save their lives. Thus, upon the sight of a predator they can choose to freeze, to escape or to confront. And If for example they choose to escape, further decisions implicating the moment, direction and speed of run should be made. These abilities to process substantial amount of information, make complex decisions, form long-term memories and organize complicated motor patterns, exist even in animals with small brains. Some of them offer particular advantages for the neuroethological approach. In this talk I will present results from our investigations on the abilities of the crab Neohelice (previous Chasmagnathus) granulata to deal with visual danger stimuli, and the role of a group of motion-sensitive giant neurons in these behaviors. I will also show preliminary results on the prey capture abilities of the crab. Our studies comprise behavioral analyses in the field and the laboratory, neuroanatomy, in vivo intracellular electrophysiology and calcium imaging, and modeling.