IFIBYNE   05513
INSTITUTO DE FISIOLOGIA, BIOLOGIA MOLECULAR Y NEUROCIENCIAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Polarization vision in crabs: a two-channel detection system?
Autor/es:
MARTÍN BERÓN DE ASTRADA; MELANIE AILIN BASNAK
Lugar:
Montevideo
Reunión:
Congreso; XII International Congress for Neuroethology; 2016
Institución organizadora:
International Society for Neurethology
Resumen:
Polarization vision is used by many different species in vital tasks, such as orientation, navigation, and contrast enhancement. Neohelice granulata, like other crabs, lives in an environment rich in polarization information. A prior experiment showed that a looming stimulus with the same intensity and spectral light composition that the background, but a 90º degree difference in the angle of polarization of light evoked the animal?s escape response. This suggests that this species is able to detect moving stimuli using only polarization cues. Our goal now was to assess if Neohelice possesses differential sensitivity to stimuli polarized with different angles. To achieve this, we presented looming stimuli in a modified LCD screen, placed to one side of a rotating sphere where the animals could walk freely. The monitor was mounted on a rotating device. The stimuli held a constant 90º polarization contrast with the background. Thus, by rotating the ensemble, the two main polarization vectors entered the crab?s eye with different angles. We quantified the escape response and found it to be greater for those stimuli for which the two E-vectors? angles were vertical and horizontal. This result suggests that Neohelice?s photoreceptors have better sensitivity for vertically and horizontally polarized light. This interpretation is consistent with anatomical studies that evidence an orthogonal pattern of the photoreceptor?s microvilli in the eyes of decapods. We are now conducting electrophysiological recordings from Neohelice?s photoreceptors to characterize their polarization sensitivity, an issue we expect to discuss with visitors at the current poster presentation.