Cortical feedback depolarization waves: A mechanism of top-down influence on early visual areas
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- Per E. Roland
- Divisions of *Brain Research and
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- Akitoshi Hanazawa
- Divisions of *Brain Research and
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- Calle Undeman
- Divisions of *Brain Research and
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- David Eriksson
- Divisions of *Brain Research and
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- Tamas Tompa
- Divisions of *Brain Research and
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- Hiroyuki Nakamura
- Developmental Anatomy, Department of Neuroscience, Karolinska Institute, S171 77 Solna, Sweden
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- Sonata Valentiniene
- Divisions of *Brain Research and
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- Bashir Ahmed
- Divisions of *Brain Research and
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説明
<jats:p>Despite the lack of direct evidence, it is generally believed that top-down signals are mediated by the abundant feedback connections from higher- to lower-order sensory areas. Here we provide direct evidence for a top-down mechanism. We stained the visual cortex of the ferret with a voltage-sensitive dye and presented a short-duration contrast square. This elicited an initial feedforward and lateral spreading depolarization at the square representation in areas 17 and 18. After a delay, a broad feedback wave (FBW) of neuron peak depolarization traveled from areas 21 and 19 toward areas 18 and 17. In areas 18 and 17, the FBW contributed the peak depolarization of dendrites of the neurons representing the square, after which the neurons decreased their depolarization and firing. Thereafter, the peak depolarization surrounded the figure representation over most of areas 17 and 18 representing the background. Thus, the FBW is an example of a well behaved long-range communication from higher-order visual areas to areas 18 and 17, collectively addressing very large populations of neurons representing the visual scene. Through local interaction with feedforward and lateral spreading depolarization, the FBW differentially activates neurons representing the object and neurons representing the background.</jats:p>
収録刊行物
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- Proceedings of the National Academy of Sciences
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Proceedings of the National Academy of Sciences 103 (33), 12586-12591, 2006-08-15
Proceedings of the National Academy of Sciences