Abstract
The primary somatosensory cortex (S1) contains a complete body map that mirrors the subcortical maps developed by peripheral sensory input projecting to the sensory hindbrain, the thalamus and then S1. Peripheral changes during development alter these maps through 'bottom-up' plasticity. Unknown is how S1 size influences map organization and whether an altered S1 map feeds back to affect subcortical maps. We show that the size of S1 in mice is significantly reduced by cortex-specific deletion of Pax6, resulting in a reduced body map and loss of body representations by an exclusion of later-differentiating sensory thalamocortical input. An initially normal sensory thalamus was repatterned to match the aberrant S1 map by apoptotic deletion of thalamic neurons representing body parts with axons excluded from S1. Deleted representations were rescued by altering competition between thalamocortical axons using sensory deprivation or increasing the size of S1. Thus, S1 size determined the resolution and completeness of body maps and engaged 'top-down' plasticity that repatterned the sensory thalamus to match S1.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Apoptosis
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Axons / physiology
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Body Image
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Eye Proteins / genetics
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Eye Proteins / physiology
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Female
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Homeodomain Proteins / genetics
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Homeodomain Proteins / physiology
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Male
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Mice
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Mice, Inbred C57BL
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Mice, Knockout
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Mice, Transgenic
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Neural Pathways / physiology
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Neuronal Plasticity / physiology*
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Neurons / physiology
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Organ Specificity
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PAX6 Transcription Factor
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Paired Box Transcription Factors / deficiency
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Paired Box Transcription Factors / genetics
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Paired Box Transcription Factors / physiology
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Posterior Thalamic Nuclei / growth & development
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Posterior Thalamic Nuclei / physiology*
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Recombinant Fusion Proteins / physiology
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Repressor Proteins / deficiency
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Repressor Proteins / genetics
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Repressor Proteins / physiology
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Rhombencephalon / physiology
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Sensation / physiology
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Somatosensory Cortex / pathology
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Somatosensory Cortex / physiology*
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Vibrissae / innervation
Substances
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Eye Proteins
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Homeodomain Proteins
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PAX6 Transcription Factor
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Paired Box Transcription Factors
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Pax6 protein, mouse
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Recombinant Fusion Proteins
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Repressor Proteins