Some of our accomplishments

Research in the Active Perception Laboratory has uncovered important principles on how humans process visual information and identified sensorimotor strategies critical for normal visual functions. Many findings follow from testing predictions of our theory of space-time encoding, a theory of how the visual system establishes spatial representations. Representative recent findings include:

• Luminance modulations from small eye movements enhance vision of fine spatial details (Rucci et al, Nature 2007)
• Temporal modulations from fixational eye drifts are matched to the characteristics of the natural visual world (Kuang et al, Current Biology, 2012)
• Fixational drifts partly compensate for the instability of the head during normal head-free fixation (Poletti et al, Current Biology, 2015)
• Tuning of minute eye movements (both drift and microsaccades) is critical to achieve normal visual acuity (Intoy & Rucci, Nature Communications, 2020)
• Microsaccades precisely relocate gaze during normal examination of fine spatial patterns (Ko et al, Nature Neuroscience 2010)
• Microsaccades compensate for non-uniform vision within the central fovea (Poletti et al, Current Biology, 2013)
• Microsaccades adapt to visuomotor contingencies (Havermann et al, J. Neurosci., 2014)
• Microsaccades follow stereotypical cognitive strategies (Shelckova & Poletti, Proc. National Academy of Sciences, 2020)
• Attention can be precisely allocated within the central fovea (Poletti et al, Nature Neuroscience, 2017)
• Microsaccades are accompanied by attentional modulations in the central fovea (Zhang et al, Current Biology, 2021)
• The saccade-fixation cycle establishes a coarse-to-fine perceptual dynamics (Boi et al, Current Biology, 2018)
• During viewing of natural scenes, luminance modulations from saccades also equalize power on the retina but on narrower frequency range than drift. As a consequence the bandwidth of equalized input power oscillates during the saccade-fixation cycle (Zhao et al, Current Biology, 2020).
• Eye muscle proprioception contributes to representing space across saccades (Poletti et al, J. Neurosci., 2013)
• A rapid and non-uniform modulation occurs in the fovea at the time of saccades. A suppression in sensitivity is rapidly followed by a selective enhancement at the very center of gaze (Intoy et al, Proceeding of the National Academy of Sciences, 2021)
• The normal instability of head yields above threshold parallax information during natural fixation (Aytekin & Rucci, Vision Research 2012)

Our work has also led to the development of new tools for experimental studies in visual neuroscience. These systems are at the foundations of many of our findings, as they have enabled measurements and sensorimotor manipulations that were not before possible. Notable devices include:

• EyeRIS, a system for flexible gaze-contingent display control (Santini et al, 2007). We have completely redesigned this system in 2021.
• A digital DPI eye-tracker, a system that enables precise measurement of eye movements and, combined with EyeRIS, accurate gaze localization (US Patent 16/550,831)
• The oscillating field monitor, an eye-tracker than enables high-resolution recording of eye movements during normal head movements (Eibenberger et al, 2016)