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The Lingering Effects of an Artificial Blind Spot
BACKGROUND: When steady fixation is maintained on the centre of a large patch of texture, holes in the periphery of the texture rapidly fade from awareness, producing artificial scotomata (i.e., invisible areas of reduced vision, like the natural ‘blind spot’). There has been considerable controvers...
Autores principales: | , , |
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Formato: | Texto |
Lenguaje: | English |
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Public Library of Science
2007
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1797615/ https://www.ncbi.nlm.nih.gov/pubmed/17327917 http://dx.doi.org/10.1371/journal.pone.0000256 |
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author | Morgan, Michael J. McEwan, William Solomon, Joshua |
author_facet | Morgan, Michael J. McEwan, William Solomon, Joshua |
author_sort | Morgan, Michael J. |
collection | PubMed |
description | BACKGROUND: When steady fixation is maintained on the centre of a large patch of texture, holes in the periphery of the texture rapidly fade from awareness, producing artificial scotomata (i.e., invisible areas of reduced vision, like the natural ‘blind spot’). There has been considerable controversy about whether this apparent ‘filling in’ depends on a low-level or high-level visual process. Evidence for an active process is that when the texture around the scotomata is suddenly removed, phantasms of the texture appear within the previous scotomata. METHODOLOGY: To see if these phantasms were equivalent to real low-level signals, we measured contrast discrimination for real dynamic texture patches presented on top of the phantasms. PRINCIPAL FINDINGS: Phantasm intensity varied with adapting contrast. Contrast discrimination depended on both (real) pedestal contrast and phantasm intensity, in a manner indicative of a common sensory threshold. The phantasms showed inter-ocular transfer, proving that their effects are cortical rather than retinal. CONCLUSIONS: We show that this effect is consistent with a tonic spreading of the adapting texture into the scotomata, coupled with some overall loss of sensitivity. Our results support the view that ‘filling in’ happens at an early stage of visual processing, quite possibly in primary visual cortex (V1). |
format | Text |
id | pubmed-1797615 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2007 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-17976152007-02-28 The Lingering Effects of an Artificial Blind Spot Morgan, Michael J. McEwan, William Solomon, Joshua PLoS One Research Article BACKGROUND: When steady fixation is maintained on the centre of a large patch of texture, holes in the periphery of the texture rapidly fade from awareness, producing artificial scotomata (i.e., invisible areas of reduced vision, like the natural ‘blind spot’). There has been considerable controversy about whether this apparent ‘filling in’ depends on a low-level or high-level visual process. Evidence for an active process is that when the texture around the scotomata is suddenly removed, phantasms of the texture appear within the previous scotomata. METHODOLOGY: To see if these phantasms were equivalent to real low-level signals, we measured contrast discrimination for real dynamic texture patches presented on top of the phantasms. PRINCIPAL FINDINGS: Phantasm intensity varied with adapting contrast. Contrast discrimination depended on both (real) pedestal contrast and phantasm intensity, in a manner indicative of a common sensory threshold. The phantasms showed inter-ocular transfer, proving that their effects are cortical rather than retinal. CONCLUSIONS: We show that this effect is consistent with a tonic spreading of the adapting texture into the scotomata, coupled with some overall loss of sensitivity. Our results support the view that ‘filling in’ happens at an early stage of visual processing, quite possibly in primary visual cortex (V1). Public Library of Science 2007-02-28 /pmc/articles/PMC1797615/ /pubmed/17327917 http://dx.doi.org/10.1371/journal.pone.0000256 Text en This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. https://creativecommons.org/publicdomain/zero/1.0/ This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration, which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. |
spellingShingle | Research Article Morgan, Michael J. McEwan, William Solomon, Joshua The Lingering Effects of an Artificial Blind Spot |
title | The Lingering Effects of an Artificial Blind Spot |
title_full | The Lingering Effects of an Artificial Blind Spot |
title_fullStr | The Lingering Effects of an Artificial Blind Spot |
title_full_unstemmed | The Lingering Effects of an Artificial Blind Spot |
title_short | The Lingering Effects of an Artificial Blind Spot |
title_sort | lingering effects of an artificial blind spot |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1797615/ https://www.ncbi.nlm.nih.gov/pubmed/17327917 http://dx.doi.org/10.1371/journal.pone.0000256 |
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