Intrasession and Intersession Reproducibility of Artificial Scotoma pRF Mapping Results at Ultra- High Fields
Date
2022Author
Linhardt, David
Pawloff, Maximilian
Woletz, Michael
Hummer, Allan
Tik, Martin
Vasileiadi, Maria
Ritter, Markus
Lerma-Usabiaga, Garikoitz
Schmidt-Erfurth, Ursula
Windischberger, Christian
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Intrasession and Intersession Reproducibility of Artificial Scotoma pRF Mapping Results at Ultra-High Fields David Linhardt, Maximilian Pawloff, Michael Woletz, Allan Hummer, Martin Tik, Maria Vasileiadi, Markus Ritter, Garikoitz Lerma-Usabiaga, Ursula Schmidt-Erfurth, Christian Windischberger eNeuro 6 September 2022, 9 (5) ENEURO.0087-22.2022; DOI: 10.1523/ENEURO.0087-22.2022
eNeuro
eNeuro
Abstract
Functional magnetic resonance imaging (fMRI) combined with population receptive field (pRF) mapping allows
for associating positions on the visual cortex to areas on the visual field. Apart from applications in healthy
subjects, this method can also be used to examine dysfunctions in patients suffering from partial visual field
losses. While such objective measurement of visual deficits (scotoma) is of great importance for, e.g., longitudinal
studies addressing treatment effects, it requires a thorough assessment of accuracy and reproducibility
of the results obtained. In this study, we quantified the reproducibility of pRF mapping results within and
across sessions in case of central visual field loss in a group of 15 human subjects. We simulated scotoma by
masking a central area of 2° radius from stimulation to establish ground-truth conditions. This study was performed
on a 7T ultra-high field MRI scanner for increased sensitivity. We found excellent intrasession and intersession
reproducibility for the pRF center position (Spearman correlation coefficients for x, y: .0.95;
eccentricity: .0.87; polar angle: .0.98), but only modest reproducibility for pRF size (Spearman correlation
coefficients around 0.4). We further examined the scotoma detection performance using an automated method
based on a reference dataset acquired with full-field stimulation. For the 2° artificial scotoma, the group-averaged
scotoma sizes were estimated at between 1.92° and 2.19° for different sessions. We conclude that pRF
mapping of visual field losses yields robust, reproducible measures of retinal function and suggest the use of
pRF mapping as an objective method for monitoring visual deficits during therapeutic interventions or disease
progression.