## The Peripheral Stereo-Threshold Project ## ---------- @[OSF](yauxr) This project proposes a method to measure stereoscopic threshold at fovea and in periphery. The stereoacuity threshold can be defined as the smallest disparity that elicits a reliable depth percept. This project aims at measuring stereoacuity in different parts of the visual filed, using a psychophysical experiment. To measure stereoacuity, we present two small spots, one having a greater disparity than the other, on the upper and lower vertical meridians and on the left and right horizontal meridians. Subjects indicate the one that appeared nearer. Also, the classical measurement of stereoacuity is performed at fixation, but not farther of nearer than fixation. Differently from this classical approach, we measured stereoacuity with different disparity pedestals (e.g., farther or closer than fixation). The proposed method has been used to investigate the effectiveness of the crossed-uncrossed overlap or retino-cortical projections. If the naso-temporal split in the retina were precise, the visual system would have problems evaluating disparities near the vertical meridian. If instead there were some crossed-uncrossed overlap, the functional field should extend on either side of the vertical meridian. We then evaluated the stereo-threshold along the vertical meridian and compared it to the horizontal meridian. We find no evidence for deficits, assessing the utility of the crossed-uncrossed overlap for disparity computation. Detailed information about the experiment, data collection and analysis can be found in: [Gibaldi, Agostino, Noah C. Benson, and Martin S. Banks. Crossed-Uncrossed Projections from Primate Retina are Adapted to Disparities of Natural Scenes. PNAS (in press).][1] The project is made of two parts, one for [performing the psychophysical experiment][2] and one for [data analysis][3]. [1]: http://inpress [2]: https://osf.io/74hgx/wiki/PsychophysicalExperiment/ [3]: https://osf.io/74hgx/wiki/DataAnalysis/