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Published on: June 26, 2012
A mapping label required for normal scale of body representation in the cortex
P Vanderhaeghen1, Q Lu, N Prakash
1Department of Cell Biology and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115, USA.
Nature Neuroscience
|March 22, 2000
Summary
Genetically determined positional labels, like Ephrin-A5, guide the somatosensory cortex (S1) body map. Disrupting these labels, such as Ephrin-A5 gene, significantly alters the map
Area of Science:
- Neuroscience
- Developmental Biology
- Genetics
Background:
- The neocortical primary somatosensory area (S1) contains a body surface map.
- Cortical area allocation reflects functional importance (e.g., face, hands).
- The role of genetic positional labels in this mapping is unclear.
Purpose of the Study:
- Investigate the role of genetically determined positional labels in neocortical mapping.
- Determine how Ephrin-A5/EphA4 gradients influence thalamocortical axon guidance.
- Analyze the impact of Ephrin-A5 gene disruption on the S1 body map.
Main Methods:
- In vitro axon guidance assays using Ephrin-A5.
- Genetic disruption of the Ephrin-A5 gene in mice.
- Analysis of the S1 body map in developing and adult mice.
Main Results:
- Ephrin-A5 and EphA4 exhibit matching medial > lateral gradients in S1 and the thalamic ventrobasal (VB) complex.
- Ephrin-A5 specifically influences VB axon guidance in vitro.
- Ephrin-A5 gene disruption causes significant, topographically specific distortions in the S1 body map, altering regional areas by up to 50%.
Conclusions:
- Provides evidence for within-area thalamocortical mapping labels.
- Demonstrates that genetic differences can induce lasting changes in the relative scale of topographic map regions.
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