PisaVisionLab

  • Full Screen
  • Wide Screen
  • Narrow Screen
  • Increase font size
  • Default font size
  • Decrease font size

Join Us on Facebook

Alessandro Benedetto

E-mail Print PDF
  • Alessandro Benedetto

PhD Student in Neuroscience, University of Florence

Contacts

  • Email: alessandro.benedetto ( AT ) unifi.it

Research laboratories

  • Department of Neuroscience, Psychology, Pharmacology and Child Health, Univesity of Florence
  • Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa
  • CNR Institute of Neuroscience, Pisa

Education

  • 2013-2016: PhD course in Neuroscience - Dottorato Toscano di Neuroscienze (XXIX ciclo).
  • 2011-2013: Master degree in Psychology - Cognitive Neuroscience. University Vita-Salute San Raffaele, Milano.
  • 2008-2011: Bachelor in Philosophy of Mind and Language. University Vita-Salute San Raffaele, Milano.

Current research and interests

  • Neural oscillations
  • Time perception
  • Attention
  • Music and the brain

Conferences

  • P.Binda, A.Benedetto. Cortical control of the pupillary light response. 9th FENS (Poster). Milan, Italy, 2014.
  • A.Benedetto, G.M.Cicchini, D.Spinelli, D.C.Burr, M.C.Morrone. Luminance level rhythmically modulates early sensory function. New Perspectives in Neuroscience: Research Results of Young Italian Neuroscientists (Poster). Naples, Italy, 26/02/2015.
  • A.Benedetto, M.C.Morrone, D.Burr. Audio-Visual Temporal-Order Judgment Reveals Rhythmic Oscillations in Temporal Bias. International Multisensory Research Forum 2015 (Poster). Pisa, Italy, 13-16/06/2015.
  • A.Benedetto, D.Burr, D.Spinelli, M.C.Morrone. Rhythmic modulation of human visual sensitivity depends on luminance. European Conference on Visual Perception 2015 (Poster). Liverpool, UK, 23-27/08/2015.
  • A.Benedetto, D.Spinelli, M.C. Morrone. Rhythmic modulation of visual contrast discrimination triggered by action. Oscillatory processes in perception and cognition (Talk). Toulouse, France, 9/12/2015.
  • A.Benedetto, M.C.Morrone. Saccadic preparation triggers visual oscillations in contrast sensitivity. International Multisensory Research Forum 2016 (Talk). Suzhou, Cina, 15-18/06/2016.

Theses

  • "A Behavioral Study of Sensorimotor Integration in Metrical Coding". Master's Thesis, University Vita-Salute San Raffaele Milano (2013). Supervisor: G. Baud-Bovy.
  • "The temporal dynamics of vision for action and perception". Doctoral Thesis, University of Florence (03/04/2017). Supervisor: M.C. Morrone.


Publications

2017

Benedetto, A. & Morrone, M.C. (2017). Saccadic suppression is embedded within extended oscillatory modulation of sensitivity, J Neurosci, PDF

Action and perception are intimately coupled systems; one clear case is saccadic suppression, the reduced visibility around the time of saccades, important in mediating visual stability; another is the oscillatory modulation of visibility synchronized with hand action. To suppress effectively the spurious retinal motion generated by the eye movements, it is crucial that saccadic suppression and saccadic onset be temporally synchronous. However, the mechanisms that determine this temporal synchrony are unknown. We investigated the effect of saccades on contrast discrimination sensitivity over a long period stretching over more than 1 second before and after saccade execution. Human subjects made horizontal saccades at will to two stationary saccadic targets separated by 20 degrees degrees. At a random interval, a brief Gabor patch was displayed between the two fixations in either the upper or lower visual field, and the subject had to detect its location. Strong saccadic suppression was measured between -50 and 50 ms from saccadic onset. However, the suppression was systematically embedded in a trough of oscillations of contrast sensitivity that fluctuated rhythmically in the delta range (at about 3 Hz), commencing about one second before saccade execution and lasting for up to one second after the saccade. The results show that saccadic preparation and visual sensitivity oscillations are coupled, and the coupling might be instrumental in temporally aligning the initiation of the saccade with the visual suppression.Significant statementSaccades are known to produce a suppression of contrast sensitivity at saccadic onset and an enhancement after saccadic offset. Here we show that these dynamics are systematically embedded in visual oscillations of contrast sensitivity that fluctuate rhythmically in the delta range (at about 3 Hz), commencing about one second before saccade execution and lasting for up to one second after the saccade. The results show that saccadic preparation and visual sensitivity oscillations are coupled, and the coupling might be instrumental in aligning temporally the initiation of the saccade with the visual suppression.


2016

Benedetto, A. & Binda, P. (2016). Dissociable saccadic suppression of pupillary and perceptual responses to light, J Neurophysiol, 3 (115), 1243-1251. PDF

We measured pupillary constrictions in response to full-screen flashes of variable luminance, occurring either at the onset of a saccadic eye movement or well before/after it. A large fraction of perisaccadic flashes were undetectable to the subjects, consistent with saccadic suppression of visual sensitivity. Likewise, pupillary responses to perisaccadic flashes were strongly suppressed. However, the two phenomena appear to be dissociable. Across subjects and luminance levels of the flash stimulus, there were cases in which conscious perception of the flash was completely depleted yet the pupillary response was clearly present, as well as cases in which the opposite occurred. On one hand, the fact that pupillary light responses are subject to saccadic suppression reinforces evidence that this is not a simple reflex but depends on the integration of retinal illumination with complex "extraretinal" cues. On the other hand, the relative independence of pupillary and perceptual responses suggests that suppression acts separately on these systems-consistent with the idea of multiple visual pathways that are differentially affected by saccades.

Benedetto, A., Spinelli, D. & Morrone, M. C. (2016). Rhythmic modulation of visual contrast discrimination triggered by action, Proceedings of the Royal Society of London B: Biological Sciences, 1831 (283), PDF


Recent evidence suggests that ongoing brain oscillations may be instrumental in binding and integrating multisensory signals. In this experiment, we investigated the temporal dynamics of visual–motor integration processes. We show that action modulates sensitivity to visual contrast discrimination in a rhythmic fashion at frequencies of about 5 Hz (in the theta range), for up to 1 s after execution of action. To understand the origin of the oscillations, we measured oscillations in contrast sensitivity at different levels of luminance, which is known to affect the endogenous brain rhythms, boosting the power of alpha-frequencies. We found that the frequency of oscillation in sensitivity increased at low luminance, probably reflecting the shift in mean endogenous brain rhythm towards higher frequencies. Importantly, both at high and at low luminance, contrast discrimination showed a rhythmic motor-induced suppression effect, with the suppression occurring earlier at low luminance. We suggest that oscillations play a key role in sensory–motor integration, and that the motor-induced suppression may reflect the first manifestation of a rhythmic oscillation.

You are here: People Graduate Students Alessandro Benedetto