Brain Imaging Meeting

Dear Colleagues,

we would like to invite you to upcoming Brain Imaging Meeting organized by Laboratory of Brain Imaging (LOBI) and Laboratory of Language Neurobiology (LLN). The seminar will take place on Wednesday 21.04.2021 at 2.30 PM, via google meet platform under the link:
During the meeting Marco Ninghetto, Msc - LOBI will present a talk entitled:
The 15 minutes of narrowing visual fields affects diameters of receptive fields in V1


Recently we showed that it is possible to measure simultaneously properties of central vision, the fine acuity, and of peripheral vision the motion perception. We designed a motion-acuity task based on discrimination between a circle and an ellipse matched for surface, build from random dot kinematograms (RDK). The two shapes were separated from the background RDK by the motion of dots by coherence, direction, or velocity. Motion was carried in positive or negative contrast. We found that the velocity-based acuity task in negative contrast was most challenging as compared to positive contrast (Kozak et al., 2021). A bigger number of neurons with small receptive fields process the fine details of the objects presented at the center of the visual field, while the peripheral receptive fields with wider diameter, are sensitive to motion in negative contrast. The size of receptive field is not stable over time, and it is primarily shaped during the development and successively by experience and events. To gain insight into the dynamics of the rearrangement when the peripheral vision is missing, we narrowed visual fields for a short amount of time (15 minutes), leaving intact 10 visual degrees of central vision. We noticed that the significant differences in receptive field diameter between hemispheres were unified when the peripheries were excluded. Despite the individual discrepancies, we demonstrated a significant shift of spared narrow foveal receptive fields to wider diameters after limiting visual stimulation. Further, we found a correlation between the size of receptive fields and motion-acuity thresholds: the increase of receptive field diameter correlates with lower acuity in negative contrast velocity-acuity task. With these results, we are left with a main question: does narrowing the visual fields cause central receptive fields to acquire peripheral characteristics?

See you there!
Brain Imaging Meeting Team
Date of publication
15 April 2021
Date of event