Are v1 simple cells optimized for visual occlusions? A comparative study.
Simple cells in primary visual cortex were famously found to respond to low-level image components such as edges. Sparse coding and independent component analysis (ICA) emerged as the standard computational models for simple cell coding because they linked their receptive fields to the statistics of...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2013-01-01
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| Series: | PLoS Computational Biology |
| Online Access: | http://europepmc.org/articles/PMC3675001?pdf=render |
| _version_ | 1818577891333505024 |
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| author | Jörg Bornschein Marc Henniges Jörg Lücke |
| author_facet | Jörg Bornschein Marc Henniges Jörg Lücke |
| author_sort | Jörg Bornschein |
| collection | DOAJ |
| description | Simple cells in primary visual cortex were famously found to respond to low-level image components such as edges. Sparse coding and independent component analysis (ICA) emerged as the standard computational models for simple cell coding because they linked their receptive fields to the statistics of visual stimuli. However, a salient feature of image statistics, occlusions of image components, is not considered by these models. Here we ask if occlusions have an effect on the predicted shapes of simple cell receptive fields. We use a comparative approach to answer this question and investigate two models for simple cells: a standard linear model and an occlusive model. For both models we simultaneously estimate optimal receptive fields, sparsity and stimulus noise. The two models are identical except for their component superposition assumption. We find the image encoding and receptive fields predicted by the models to differ significantly. While both models predict many Gabor-like fields, the occlusive model predicts a much sparser encoding and high percentages of 'globular' receptive fields. This relatively new center-surround type of simple cell response is observed since reverse correlation is used in experimental studies. While high percentages of 'globular' fields can be obtained using specific choices of sparsity and overcompleteness in linear sparse coding, no or only low proportions are reported in the vast majority of studies on linear models (including all ICA models). Likewise, for the here investigated linear model and optimal sparsity, only low proportions of 'globular' fields are observed. In comparison, the occlusive model robustly infers high proportions and can match the experimentally observed high proportions of 'globular' fields well. Our computational study, therefore, suggests that 'globular' fields may be evidence for an optimal encoding of visual occlusions in primary visual cortex. |
| first_indexed | 2024-12-16T06:37:07Z |
| format | Article |
| id | doaj.art-ae39401bc5e74b2cbebe0bb4b9c45af9 |
| institution | Directory Open Access Journal |
| issn | 1553-734X 1553-7358 |
| language | English |
| last_indexed | 2024-12-16T06:37:07Z |
| publishDate | 2013-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Computational Biology |
| spelling | doaj.art-ae39401bc5e74b2cbebe0bb4b9c45af92022-12-21T22:40:46ZengPublic Library of Science (PLoS)PLoS Computational Biology1553-734X1553-73582013-01-0196e100306210.1371/journal.pcbi.1003062Are v1 simple cells optimized for visual occlusions? A comparative study.Jörg BornscheinMarc HennigesJörg LückeSimple cells in primary visual cortex were famously found to respond to low-level image components such as edges. Sparse coding and independent component analysis (ICA) emerged as the standard computational models for simple cell coding because they linked their receptive fields to the statistics of visual stimuli. However, a salient feature of image statistics, occlusions of image components, is not considered by these models. Here we ask if occlusions have an effect on the predicted shapes of simple cell receptive fields. We use a comparative approach to answer this question and investigate two models for simple cells: a standard linear model and an occlusive model. For both models we simultaneously estimate optimal receptive fields, sparsity and stimulus noise. The two models are identical except for their component superposition assumption. We find the image encoding and receptive fields predicted by the models to differ significantly. While both models predict many Gabor-like fields, the occlusive model predicts a much sparser encoding and high percentages of 'globular' receptive fields. This relatively new center-surround type of simple cell response is observed since reverse correlation is used in experimental studies. While high percentages of 'globular' fields can be obtained using specific choices of sparsity and overcompleteness in linear sparse coding, no or only low proportions are reported in the vast majority of studies on linear models (including all ICA models). Likewise, for the here investigated linear model and optimal sparsity, only low proportions of 'globular' fields are observed. In comparison, the occlusive model robustly infers high proportions and can match the experimentally observed high proportions of 'globular' fields well. Our computational study, therefore, suggests that 'globular' fields may be evidence for an optimal encoding of visual occlusions in primary visual cortex.http://europepmc.org/articles/PMC3675001?pdf=render |
| spellingShingle | Jörg Bornschein Marc Henniges Jörg Lücke Are v1 simple cells optimized for visual occlusions? A comparative study. PLoS Computational Biology |
| title | Are v1 simple cells optimized for visual occlusions? A comparative study. |
| title_full | Are v1 simple cells optimized for visual occlusions? A comparative study. |
| title_fullStr | Are v1 simple cells optimized for visual occlusions? A comparative study. |
| title_full_unstemmed | Are v1 simple cells optimized for visual occlusions? A comparative study. |
| title_short | Are v1 simple cells optimized for visual occlusions? A comparative study. |
| title_sort | are v1 simple cells optimized for visual occlusions a comparative study |
| url | http://europepmc.org/articles/PMC3675001?pdf=render |
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