Cargando…
Direct evidence for encoding of motion streaks in human visual cortex
Temporal integration in the visual system causes fast-moving objects to generate static, oriented traces (‘motion streaks’), which could be used to help judge direction of motion. While human psychophysics and single-unit studies in non-human primates are consistent with this hypothesis, direct neur...
Autores principales: | , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society
2013
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3574303/ https://www.ncbi.nlm.nih.gov/pubmed/23222445 http://dx.doi.org/10.1098/rspb.2012.2339 |
_version_ | 1782259581411393536 |
---|---|
author | Apthorp, Deborah Schwarzkopf, D. Samuel Kaul, Christian Bahrami, Bahador Alais, David Rees, Geraint |
author_facet | Apthorp, Deborah Schwarzkopf, D. Samuel Kaul, Christian Bahrami, Bahador Alais, David Rees, Geraint |
author_sort | Apthorp, Deborah |
collection | PubMed |
description | Temporal integration in the visual system causes fast-moving objects to generate static, oriented traces (‘motion streaks’), which could be used to help judge direction of motion. While human psychophysics and single-unit studies in non-human primates are consistent with this hypothesis, direct neural evidence from the human cortex is still lacking. First, we provide psychophysical evidence that faster and slower motions are processed by distinct neural mechanisms: faster motion raised human perceptual thresholds for static orientations parallel to the direction of motion, whereas slower motion raised thresholds for orthogonal orientations. We then used functional magnetic resonance imaging to measure brain activity while human observers viewed either fast (‘streaky’) or slow random dot stimuli moving in different directions, or corresponding static-oriented stimuli. We found that local spatial patterns of brain activity in early retinotopic visual cortex reliably distinguished between static orientations. Critically, a multivariate pattern classifier trained on brain activity evoked by these static stimuli could then successfully distinguish the direction of fast (‘streaky’) but not slow motion. Thus, signals encoding static-oriented streak information are present in human early visual cortex when viewing fast motion. These experiments show that motion streaks are present in the human visual system for faster motion. |
format | Online Article Text |
id | pubmed-3574303 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | The Royal Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-35743032013-03-01 Direct evidence for encoding of motion streaks in human visual cortex Apthorp, Deborah Schwarzkopf, D. Samuel Kaul, Christian Bahrami, Bahador Alais, David Rees, Geraint Proc Biol Sci Research Articles Temporal integration in the visual system causes fast-moving objects to generate static, oriented traces (‘motion streaks’), which could be used to help judge direction of motion. While human psychophysics and single-unit studies in non-human primates are consistent with this hypothesis, direct neural evidence from the human cortex is still lacking. First, we provide psychophysical evidence that faster and slower motions are processed by distinct neural mechanisms: faster motion raised human perceptual thresholds for static orientations parallel to the direction of motion, whereas slower motion raised thresholds for orthogonal orientations. We then used functional magnetic resonance imaging to measure brain activity while human observers viewed either fast (‘streaky’) or slow random dot stimuli moving in different directions, or corresponding static-oriented stimuli. We found that local spatial patterns of brain activity in early retinotopic visual cortex reliably distinguished between static orientations. Critically, a multivariate pattern classifier trained on brain activity evoked by these static stimuli could then successfully distinguish the direction of fast (‘streaky’) but not slow motion. Thus, signals encoding static-oriented streak information are present in human early visual cortex when viewing fast motion. These experiments show that motion streaks are present in the human visual system for faster motion. The Royal Society 2013-02-07 /pmc/articles/PMC3574303/ /pubmed/23222445 http://dx.doi.org/10.1098/rspb.2012.2339 Text en http://creativecommons.org/licenses/by/3.0/ © 2012 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0/, which permits unrestricted use, provided the original author and source are credited. |
spellingShingle | Research Articles Apthorp, Deborah Schwarzkopf, D. Samuel Kaul, Christian Bahrami, Bahador Alais, David Rees, Geraint Direct evidence for encoding of motion streaks in human visual cortex |
title | Direct evidence for encoding of motion streaks in human visual cortex |
title_full | Direct evidence for encoding of motion streaks in human visual cortex |
title_fullStr | Direct evidence for encoding of motion streaks in human visual cortex |
title_full_unstemmed | Direct evidence for encoding of motion streaks in human visual cortex |
title_short | Direct evidence for encoding of motion streaks in human visual cortex |
title_sort | direct evidence for encoding of motion streaks in human visual cortex |
topic | Research Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3574303/ https://www.ncbi.nlm.nih.gov/pubmed/23222445 http://dx.doi.org/10.1098/rspb.2012.2339 |
work_keys_str_mv | AT apthorpdeborah directevidenceforencodingofmotionstreaksinhumanvisualcortex AT schwarzkopfdsamuel directevidenceforencodingofmotionstreaksinhumanvisualcortex AT kaulchristian directevidenceforencodingofmotionstreaksinhumanvisualcortex AT bahramibahador directevidenceforencodingofmotionstreaksinhumanvisualcortex AT alaisdavid directevidenceforencodingofmotionstreaksinhumanvisualcortex AT reesgeraint directevidenceforencodingofmotionstreaksinhumanvisualcortex |