Summary
This study reveals that the extracellular matrix molecule reelin is essential for guiding intrinsically photosensitive retinal ganglion cell (ipRGC) axons to their correct targets in the ventral LGN and intergeniculate leaflet, which are critical relay stations for non-image-forming light responses including circadian entrainment. Disruption of reelin causes ipRGC axon mistargeting, which has implications for understanding developmental disorders affecting circadian photoentrainment and non-visual light responses.
Key Findings
- Reelin is selectively enriched in the vLGN and IGL (but not dLGN) during retinogeniculate circuit formation, suggesting a targeting role specific to non-image-forming pathways.
- In reelin-deficient (reln(rl/rl)) mice, ipRGC axons showed reduced innervation of the vLGN and IGL and were misrouted into adjacent non-retino-recipient thalamic nuclei.
- Image-forming RGC axons and layer VI cortical neuron axons correctly targeted the dLGN in reelin mutants, indicating that reelin's targeting role is class-specific to non-image-forming ipRGCs.
Categories
The Science of Light: This paper investigates the neural circuitry connecting ipRGCs to brain targets, directly relevant to understanding how non-image-forming photoreceptors wire into the visual system.
Eye Health & Vision: The study examines retinogeniculate targeting mechanisms that underlie proper visual system development and circuit formation.
Author(s)
J Su, CV Haner, TE Imbery, JM Brooks
Publication Year
2011
Number of Citations
62
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