Abstract
Thalamic nuclei are thought to funnel sensory information to the brain's primary cortical areas, which in turn transmit signals afresh to higher cortical areas. Here we describe a direct projection in the macaque monkey from the lateral geniculate nucleus (LGN) to the motion-selective middle temporal area (MTor V5), a cortical area not previously considered 'primary'. The constituent neurons are mostly koniocellular, send virtually no collateral axons to primary visual cortex (V1) and equal about 10% of the V1 population innervating MT. This pathway could explain the persistence of motion sensitivity in subjects following injury to V1, suggesting more generally that residual perception after damage in a primary area may arise from sparse thalamic input to 'secondary' cortical areas.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Axons / ultrastructure
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Brain Mapping
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Calcium-Calmodulin-Dependent Protein Kinase Type 2
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Calcium-Calmodulin-Dependent Protein Kinases / metabolism
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Cholera Toxin
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Dendrites / ultrastructure
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Geniculate Bodies / physiology*
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Immunohistochemistry
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Macaca mulatta / anatomy & histology*
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Macaca mulatta / physiology
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Male
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Motion Perception / physiology
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Neuronal Plasticity / physiology
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Neurons / cytology
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Neurons / physiology
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Temporal Lobe / anatomy & histology*
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Temporal Lobe / physiology
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Vision, Low / physiopathology
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Visual Cortex / anatomy & histology*
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Visual Cortex / physiology
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Visual Pathways / anatomy & histology*
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Visual Pathways / physiology
Substances
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Cholera Toxin
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Calcium-Calmodulin-Dependent Protein Kinase Type 2
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Calcium-Calmodulin-Dependent Protein Kinases