Different features of visual motion stimuli give rise to different escape response velocities in a crab

BENGOCHEA M Y BERON DE ASTRADA

Huerta Grande, Cordoba

Congreso; Congreso Argentino de Neurociencias, 2013; 2013

Sociedad Argentina de Neurociencias

The visual world presents an abundance of information that animals break down into features, such as colour, direction of movement, size, contrast, etc. Crabs are highly visual animals that display complex visually guided behaviours. In nature, these animals are preyed on mostly by gulls. In order to avoid being preyed, the crabs have to sense and integrate different characteristic of the visual stimuli. By using a walking simulator device, we studied animal's escape response when it was confronted with computer-generated visual stimuli. The stimulation consisted of figures which differed in speed, contrast or size. A black figure moving at different speeds triggered a Gaussian like curve response with its maximum at 30º/s. Figures which differed from white to black against a grey background showed a sigmoid like curve response with surprising low responses for clear figures and high responses for dark ones. The presentation of bars with different angular sizes provoked greater escape responses as the angular size increased. By performing calcium imaging in vivo we have recently shown that the activity of small field columnar neurons feeding wide field giant neurons determines the habituation of the animal escape response. Our next step is to study if the visual tuning sensitivity of these columnar neurons also determines the animal´s proneness to escape from visual danger stimuli.