Binocular Visual Integration in Neohelice granulata.

FLORENCIA SCARANO; JULIETA SZTARKER; VIOLETA MEDAN; MARTÍN BERÓN DE ASTRADA; DANIEL TOMSIC

JOURNAL OF NEUROSCIENCE

SOC NEUROSCIENCE

Lugar: Washington; Año: 2018 vol. 38 p. 6933 - 6948

0270-6474

Animals use binocular information to guide many behaviors. In highly visual arthropods, complex binocular computations involved in processing the panoramic optic flow generated during self-motion take place in the optic neuropils. However, the extent to which binocular processing of object motion occurs in these neuropils remains unknown. We investigated this in a crab, where the distance between the eyes and the extensive overlapping of their visual fields advocate for the use of binocular processing. By performing in vivo intracellular recordings from the lobula (third optic neuropil), we assessed the responses of object-motion sensitive neurons to ipsilateral or contralateral moving objects under binocular and monocular conditions. Most recorded neurons responded to stimuli seen independently with either eye, proving that each lobula receives profuse visual information from both eyes. The contribution of each eye to the binocular response varies among neurons, from those receiving comparable inputs from both eyes to those with mainly ipsilateral or contralateral components, some including contralateral inhibition. The electrophysiological profiles indicated that a similar number of neurons were recorded from their input or their output side. In monocular conditions, the first group showed shorter response delays to ipsilateral than to contralateral stimulation, while the second group showed the opposite. These results fit well with neurons conveying centripetal and centrifugal information from and toward the lobula respectively. Intracellular and massive stainings provided anatomical support for this and for direct connections between the two lobulae, but simultaneous recordings failed to reveal such connections. A simplified model circuit of interocular connections is discussed.