Cortical representation of space around the blind spot

Awater, Holger; Kerlin, Jess R.; Tong, Frank

doi:10.1167/5.8.894

Cited by 5 publications

(10 citation statements)

References 0 publications

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“…We selected a continuous region of this atlas, predicted to be within V1 with ≥80%. In all participants this revealed clusters of significant pRF fits (especially for the reverse correlation approach) at a location consistent with the expected representation of the blind spot in V1 (5, 7). However, due to artifacts a few stray vertices occasionally survived thresholding throughout the rest of V1.…”

Section: Methodssupporting

confidence: 61%

“…We therefore selected the pRFs that survived statistical thresholding in both conditions, and then computed the mean Euclidian distance between the blind spot and control estimates for these pRFs, separately for the reverse correlation and the forward-model analysis. This analysis revealed significantly smaller distances in pRF positions (t(7)=-3.6, p=0.0087) for the reverse correlation (mean=1.66°) than the forward-model (mean=2.59°).…”

Section: Resultsmentioning

confidence: 87%

“…This means that even with high spatial resolution brain imaging, only a small number of voxels encode responses from this region of V1. Nonetheless, fMRI experiments have shown that the blind spot is a discontinuity in the visual field representation: with responses to spatially separate stimuli on either side of a blind spot exciting anatomically segregated responses in V1, despite observers perceiving such a configuration as single and continuous (7, 8).…”

Section: Introductionmentioning

confidence: 99%

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Highly accurate retinotopic maps of the physiological blind spot in human visual cortex

Urale

Puckett

York

et al. 2021

Preprint

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The physiological blind spot is a naturally occurring scotoma corresponding with the optic disc in the retina of each eye. Even during monocular viewing, observers are usually oblivious to the scotoma, in part because the visual system extrapolates information from the surrounding area. Unfortunately, studying this visual field region with neuroimaging has proven difficult, as it occupies only a small part of retinotopic cortex. Here we used functional magnetic resonance imaging and a novel data-driven method for mapping the retinotopic organization in and around the blind spot representation in V1. Our approach allowed for highly accurate reconstructions of the extent of an observer’s blind spot, and out-performed conventional model-based analyses. This method opens exciting opportunities to study the plasticity of receptive fields after visual field loss, and our data add to evidence suggesting that the neural circuitry responsible for impressions of perceptual completion across the physiological blind spot most likely involves regions of extrastriate cortex – beyond V1.

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Section: Methodssupporting

confidence: 61%

Section: Resultsmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

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Highly accurate retinotopic maps of the physiological blind spot in human visual cortex

Urale

Puckett

York

et al. 2021

Preprint

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“…However, prior studies (Fiorani et al, 1992; Ramachandran, 1992; Awater et al, 2005; Matsumoto and Komatsu, 2005) have reported that no perceptual filling-in occurs when single bars are presented to just one side of the BS as used in this study. Thus, our effect cannot be explained by the traditional perspective on “filling-in” around the BS, though one appealingly parsimonious account would be that common mechanisms underlie both our distortion phenomena and filling-in around the BS.…”

Section: Discussionmentioning

confidence: 71%

"Referred Visual Sensations": Rapid Perceptual Elongation after Visual Cortical Deprivation

Dilks¹,

Baker²,

Liu³

et al. 2009

Journal of Neuroscience

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Visual perceptual distortion (i.e., elongation) has been demonstrated in a single case study after several months of cortical deprivation after a stroke. Here we asked whether similar perceptual elongation can be observed in healthy participants after deprivation and, crucially, how soon after deprivation this elongation occurs. To answer this question, we patched one eye, thus noninvasively and reversibly depriving bottom-up input to the region of primary visual cortex (V1) corresponding to the blind spot (BS) in the unpatched eye, and tested whether and how quickly elongation occurs after the onset of deprivation. Within seconds of eye patching, participants perceived rectangles adjacent to the BS to be elongated toward the BS. We attribute this perceptual elongation to rapid receptive field expansion within the deprived V1 as reported in electrophysiological studies after retinal lesions and refer to it as "referred visual sensations" (RVS). This RVS is too fast to be the result of structural changes in the cortex (e.g., the growth of new connections), instead implicating unmasking of preexisting connections as the underlying neural mechanism. These findings may shed light on other reported perceptual distortions, as well as the phenomena of "filling-in."

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“…They were explicitly instructed to calibrate it as small as necessary to preclude any residual flickering. The circular probe flickered from dark gray to light gray to be more salient than a probe with constant color (Awater, 2005). All stimuli were presented centered at the respective calibrated blind spot location.…”

Section: Blind Spotsmentioning

confidence: 99%

Humans treat unreliable filled-in percepts as more real than veridical ones

Ehinger

Häusser

Ossandón

et al. 2016

Preprint

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Humans often evaluate sensory signals according to their reliability for optimal decision-making. However, how do we evaluate percepts generated in the absence of direct input that are, therefore, completely unreliable? Here, we utilize the phenomenon of filling-in occurring at the physiological blind-spots to compare partially inferred and veridical percepts. Subjects chose between stimuli that elicit filling-in, and perceptually equivalent ones presented outside the blind-spots, looking for a Gabor stimulus without a small orthogonal inset. In ambiguous conditions, when the stimuli were physically identical and the inset was absent in both, subjects behaved opposite to optimal, preferring the blind-spot stimulus as the better example of a collinear stimulus, even though no relevant veridical information was available. Thus, a percept that is partially inferred is paradoxically considered more reliable than a percept based on external input. In other words: Humans treat filled-in inferred percepts as more real than veridical ones.

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Cortical representation of space around the blind spot

Cited by 5 publications

References 0 publications

Highly accurate retinotopic maps of the physiological blind spot in human visual cortex

Highly accurate retinotopic maps of the physiological blind spot in human visual cortex

"Referred Visual Sensations": Rapid Perceptual Elongation after Visual Cortical Deprivation

Humans treat unreliable filled-in percepts as more real than veridical ones

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