Foveal pRF properties in the visual cortex depend on the extent of stimulated visual field

Prabhakaran, Gokulraj T; Carvalho, Joana; Invernizzi, Azzurra; Kanowski, Martin; Renken, Remco; Cornelissen, Frans W.; Hoffmann, Michael B.

doi:10.1016/j.neuroimage.2020.117250

Cited by 14 publications

(20 citation statements)

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“…The width of the bar subtended 1/4th (3.45 • ) of the stimulus radius (13.8 • ). The spatial and temporal properties of the stimulus have been described in Prabhakaran et al (Prabhakaran et al, 2020). The duration of each pRF mapping scan was 192 s and the scan was repeated 6 times for the patient cohort and 4 times for the controls.…”

Section: Visual Stimulationmentioning

confidence: 99%

Functional Dynamics of Deafferented Early Visual Cortex in Glaucoma

et al. 2021

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In advanced retinitis pigmentosa with retinal lesions, the lesion projection zone (LPZ) in the early visual cortex can be driven during visual tasks, while it remains unresponsive during passive viewing. We tested whether this finding translates to advanced glaucoma, a major cause of acquired blindness. During visual stimulation, 3T fMRI scans were acquired for participants with advanced glaucoma (n = 4; age range: 51–72) and compared to two reference groups, i.e., advanced retinitis pigmentosa (n = 3; age range: 46–78) and age-matched healthy controls with simulated defects (n = 7). The participants viewed grating patterns drifting in 8 directions (12 s) alternating with uniform gray (12 s), either during passive viewing (PV), i.e., central fixation, or during a one-back task (OBT), i.e., reports of succeeding identical motion directions. As another reference, a fixation-dot task condition was included. Only in glaucoma and retinitis pigmentosa but not in controls, fMRI-responses in the lesion projection zone (LPZ) of V1 shifted from negative for PV to positive for OBT (p = 0.024 and p = 0.012, respectively). In glaucoma, these effects also reached significance in V3 (p = 0.006), while in V2 there was a non-significant trend (p = 0.069). The general absence of positive responses in the LPZ during PV underscores the lack of early visual cortex bottom-up plasticity for acquired visual field defects in humans. Trends in our exploratory analysis suggesting the task-dependent LPZ responses to be inversely related to visual field loss, indicate the benefit of patient stratification strategies in future studies with greater sample sizes. We conclude that top-down mechanisms associated with task-elicited demands rather than visual cortex remapping appear to shape LPZ responses not only in retinitis pigmentosa, but also in glaucoma. These insights are of critical importance for the development of schemes for treatment and rehabilitation in glaucoma and beyond.

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Section: Visual Stimulationmentioning

confidence: 99%

Functional Dynamics of Deafferented Early Visual Cortex in Glaucoma

et al. 2021

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“…The width of the bar subtended 1/4 th (3.45°) of the stimulus radius (13.8°). The spatial and temporal properties of the stimulus have been described in Prabhakaran et al (Prabhakaran et al, 2020). The duration of each pRF mapping scan was 192 s and the scan was repeated 6 times for the patient cohort and 4 times for the controls.…”

Section: Visual Stimulationmentioning

confidence: 99%

“…We defined the borders of primary (V1) and extra-striate visual cortex (V2 & V3) for each participant using fMRI-based pRF-mapping data. Employing a 2D-Gaussian pRF model approach described previously (Dumoulin and Wandell, 2008;Prabhakaran et al, ሻ measures were derived from these position parameters. Polar angle estimates were projected onto an inflated cortical surface and the visual areas were delineated by following the phase reversals in the polar angle data (Sereno et al, 1995).…”

Section: Visual Area Delineationmentioning

confidence: 99%

“…Although glaucoma is a prevalent disease, the scope of cortical plasticity in the deafferented portions of the early visual cortex in advanced glaucoma has only received little attention. Zhou et al reported an enlarged para-foveal representation in the visual cortex of glaucoma patients (Zhou et al, 2017), but recent investigations of simulated peripheral response dropouts in controls (Prabhakaran et al, 2020) suggest that such effects do not necessarily reflect veridical long-term cortical reorganization. This mirrors the views based on previous reports analyzing the limited nature of visual cortex plasticity for foveal deafferentation (Barton and Brewer, 2015;Baseler et al, 2011;Haak et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Functional dynamics of de-afferented early visual cortex in glaucoma

Prabhakaran

Al-Nosairy

Tempelmann

et al. 2020

Preprint

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AbstractfMRI studies in macular degeneration (MD) and retinitis pigmentosa (RP) demonstrated that responses in the lesion projection zones (LPZ) of V1 are task related, indicating significant limits of bottom-up visual system plasticity in MD and RP. In advanced glaucoma (GL), a prevalent eye disease and leading cause of blindness, the scope of visual system plasticity is currently unknown. We performed 3T fMRI in patients with extensive visual field defects due to GL (n=5), RP (n=2) and healthy controls (n=7; with simulated defects). Participants viewed contrast patterns drifting in 8 directions alternating with uniform gray and performed 3 tasks: (1) passive viewing (PV), (2) one-back task (OBT) and (3) fixation-dot task (FDT). During PV, they passively viewed the stimulus with central fixation, during OBT they reported the succession of the same two motion directions, and during FDT a change in the fixation color. In GL, LPZ responses of the early visual cortex (V1, V2 and V3) shifted from negative during PV to positive for OBT [p (corrected): V1(0.006); V2(0.04); V3(0.008)], while they were negative in the controls’ simulated LPZ for all stimulation conditions. For RP a similar pattern as for GL was observed. Consequently, activity in the de-afferented visual cortex in glaucoma is, similar to MD and RP, task-related. In conclusion, the lack of bottom-up plasticity appears to be a general feature of the human visual system. These insights are of importance for the development of treatment and rehabilitation schemes in glaucoma.HighlightsFunctional dynamics of early visual cortex LPZ depend on task demands in glaucomaBrain activity in deprived visual cortex suggests absence of large-scale remappingLimited scope of bottom-up plasticity is a general feature of human visual systemVisual system stability and plasticity is of relevance for therapeutic advances

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“…It is made available under a preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in The copyright holder for this this version posted December 15, 2020. ; https://doi.org/10.1101/2020.12.15.422942 doi: bioRxiv preprint 2008), where we estimate pRF position and size for each voxel in the brain under a Baseline condition as well as a condition of Interest (see Figure 1 for a single pRF). We can think of the Interest and Baseline conditions as repeat data (e.g., Benson et al, 2018;van Dijk, de Haas, Moutsiana, & Schwarzkopf, 2016), different attention conditions (e.g, de Haas, Schwarzkopf, Anderson, & Rees, 2014;Klein, Harvey, & Dumoulin, 2014;van Es, Theeuwes, & Knapen, 2018;Vo, Sprague, & Serences, 2017), mapping sequences (e.g., Binda, Thomas, Boynton, & Fine, 2013;Infanti & Schwarzkopf, 2020), mapping stimuli (e.g., Alvarez, de Haas, Clark, Rees, & Samuel Schwarzkopf, 2015;Binda et al, 2013;Le, Witthoft, Ben-Shachar, & Wandell, 2017;Yildirim, Carvalho, & Cornelissen, 2018), scotoma conditions (e.g., Barton & Brewer, 2015;Binda et al, 2013;Haak, Cornelissen, & Morland, 2012;Prabhakaran et al, 2020), pRF modeling techniques (e.g., Carvalho et al, 2020) or uni-and multisensory conditions (Holmes, 2009) -to name but a few examples. As a pRF model, we adopt a 2D Gaussian, where pRF position represents the center of a pRF in visual space (the center of the Gaussian) and pRF size its spatial extent (the standard deviation of the Gaussian; see Figure 1).…”

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confidence: 99%

Pitfalls in Post Hoc Analyses of Population Receptive Field Data

Stoll

Infanti

Haas

et al. 2020

Preprint

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Data binning can cope with overplotting and noise, making it a versatile tool for comparing many observations. However, it goes awry if the same observations are used for binning and contrasting. This creates an inherent circularity, leaving noise and regression to the mean insufficiently controlled. Here, we use population receptive field analyses – where data binning is commonplace – as an example to expose this flaw through simulations and empirical repeat data.

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Foveal pRF properties in the visual cortex depend on the extent of stimulated visual field

Cited by 14 publications

References 48 publications

Functional Dynamics of Deafferented Early Visual Cortex in Glaucoma

Functional Dynamics of Deafferented Early Visual Cortex in Glaucoma

Functional dynamics of de-afferented early visual cortex in glaucoma

Pitfalls in Post Hoc Analyses of Population Receptive Field Data

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