| Temporal-frequency tuning of direction selectivity in cat visual cortex. | |
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MedLine Citation:
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PMID: 1562571 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Responses of 71 cells in areas 17 and 18 of the cat visual cortex were recorded extracellularly while stimulating with gratings drifting in each direction across the receptive field at a series of temporal frequencies. Direction selectivity was most prominent at temporal frequencies of 1-2 Hz. In about 20% of the total population, the response in the nonpreferred direction increased at temporal frequencies of around 4 Hz and direction selectivity was diminished or lost. In a few cells the preferred direction reversed. One consequence of this behavior was a tendency for the preferred direction to have lower optimal temporal frequencies than the nonpreferred direction. Across the population, the preferred direction was tuned almost an octave lower. In spite of this, temporal resolution was similar in the two directions. It appeared that responses in the nonpreferred direction were suppressed at low frequencies, then recovered at higher frequencies. This phenomenon might reflect the convergence in visual cortex of lagged and nonlagged inputs from the lateral geniculate nucleus. These afferents fire about a quarter-cycle apart (i.e. are in temporal quadrature) at low temporal frequencies, but their phase difference increases to a half-cycle by about 4 Hz. Such timing differences could underlie the prevalence of direction-selective cortical responses at 1 and 2 Hz and the loss of direction selectivity in many cells by 4 or 8 Hz. |
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Authors:
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A B Saul; A L Humphrey |
Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Visual neuroscience Volume: 8 ISSN: 0952-5238 ISO Abbreviation: Vis. Neurosci. Publication Date: 1992 Apr |
Date Detail:
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Created Date: 1992-05-20 Completed Date: 1992-05-20 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 8809466 Medline TA: Vis Neurosci Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 365-72 Citation Subset: IM |
Affiliation:
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Department of Neurobiology, Anatomy, and Cell Science, University of Pittsburgh School of Medicine, PA 15261. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Cats Electrophysiology Form Perception / physiology* Geniculate Bodies / physiology Visual Cortex / physiology* |
| Grant Support | |
ID/Acronym/Agency:
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EY06034/EY/NEI NIH HHS; EY06459/EY/NEI NIH HHS; MH18273/MH/NIMH NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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