| Directional responses of visual wulst neurones to grating and plaid patterns in the awake owl. | |
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MedLine Citation:
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PMID: 17897399 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The avian retinothalamofugal pathway reaches the telencephalon in an area known as visual wulst. A close functional analogy between this area and the early visual cortex of mammals has been established in owls. The goal of the present study was to assess quantitatively the directional selectivity and motion integration capability of visual wulst neurones, aspects that have not been previously investigated. We recorded extracellularly from a total of 101 cells in awake burrowing owls. From this sample, 88% of the units exhibited modulated directional responses to sinusoidal gratings, with a mean direction index of 0.74 +/- 0.03 and tuning bandwidth of 28 +/- 1.16 degrees . A direction index higher than 0.5 was observed in 66% of the cells, thereby qualifying them as direction selective. Motion integration was tested with moving plaids, made by adding two sinusoidal gratings of different orientations. We found that 80% of direction-selective cells responded optimally to the motion direction of the component gratings, whereas none responded to the global motion of plaids, whose direction was intermediate to that of the gratings. The remaining 20% were unclassifiable. The strength of component motion selectivity rapidly increased over a 200 ms period following stimulus onset, maintaining a relatively sustained profile thereafter. Overall, our data suggest that, as in the mammalian primary visual cortex, the visual wulst neurones of owls signal the local orientated features of a moving object. How and where these potentially ambiguous signals are integrated in the owl brain might be important for understanding the mechanisms underlying global motion perception. |
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Authors:
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Jerome Baron; Lucas Pinto; Marcelo Oliveira Dias; Bruss Lima; Sergio Neuenschwander |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The European journal of neuroscience Volume: 26 ISSN: 0953-816X ISO Abbreviation: Eur. J. Neurosci. Publication Date: 2007 Oct |
Date Detail:
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Created Date: 2007-09-27 Completed Date: 2008-01-29 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8918110 Medline TA: Eur J Neurosci Country: France |
Other Details:
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Languages: eng Pagination: 1950-68 Citation Subset: IM |
Affiliation:
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Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil. jbaron@icb.ufmg.br |
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| MeSH Terms | |
Descriptor/Qualifier:
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Action Potentials
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physiology Analysis of Variance Animals Motion Perception / physiology* Neurons / physiology* Orientation / physiology* Photic Stimulation / methods Strigiformes / physiology* Telencephalon / cytology* Visual Pathways / physiology Wakefulness* |
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