RT Journal Article
SR Electronic
T1 Foveal pRF properties in the visual cortex depend on the extent of stimulated visual field
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.01.28.923045
DO 10.1101/2020.01.28.923045
A1 Prabhakaran, Gokulraj
A1 Carvalho, Joana
A1 Invernizzi, Azzurra
A1 Kanowski, Martin
A1 Renken, Remco J.
A1 Cornelissen, Frans W.
A1 Hoffmann, Michael B.
YR 2020
UL http://biorxiv.org/content/early/2020/01/29/2020.01.28.923045.abstract
AB Previous studies demonstrated that alterations in functional MRI derived receptive field (pRF) properties in cortical projection zones of retinal lesions can erroneously be mistaken for cortical large-scale reorganization in response to visual system pathologies. We tested, whether such confounds are also evident in the normal cortical projection zone of the fovea for simulated peripheral visual field defects. We applied fMRI-based visual field mapping of the central visual field at 3 Tesla in eight controls to compare the pRF properties of the central visual field of a reference condition (stimulus radius: 14°) and two conditions with simulated peripheral visual field defect, i.e., with a peripheral gray mask, stimulating only the central 7° or 4° radius. We quantified, for the cortical representation of the actually stimulated visual field, the changes in the position and size of the pRFs associated with reduced peripheral stimulation using conventional and advanced pRF modeling. We found foveal pRF-positions (≤3°) to be significantly shifted towards the periphery (p<0.05, corrected). These pRF-shifts were largest for the 4° condition [visual area (mean eccentricity shift): V1 (0.9°), V2 (0.9°), V3 (1.0°)], but also evident for the 7° condition [V1 (0.5°), V2 (0.5°), V3 (0.9°)]. Further, an overall enlargement of pRF-sizes was observed. These findings indicate the dependence of foveal pRF parameters on the spatial extent of the stimulated visual field. Consequently, our results imply that, previously reported similar findings in patients with actual peripheral scotomas need to be interpreted with caution and indicate the need for adequate control conditions in investigations of visual cortex reorganization.HighlightsFoveal pRF properties change in controls with restricted peripheral stimulationpRFs shift in position and enlarge in size for reduced stimulation extentAlterations in pRF characteristics in patients should be interpreted with cautionAdequate control conditions needed in investigations of visual cortex plasticity