Snapshots of Life: Neurons in a New Light

Mouse Midbrain

Credit: Michael Shribak, Marine Biological Laboratory, Woods Hole, MA

Birds do it, bees do it, and even educated fleas do it. No, not fall in love, as the late Ella Fitzgerald so famously sang. Birds and insects can see polarized light—that is, light waves transmitted in a single directional plane—in ways that provides them with a far more colorful and detailed view of the world than is possible with the human eye.

Still, thanks to innovations in microscope technology, scientists have been able to tap into the power of polarized light vision to explore the inner workings of many complex biological systems, including the brain. In this image, researchers used a recently developed polarized light microscope to trace the spatial orientation of neurons in a thin section of the mouse midbrain. Neurons that stretch horizontally appear green, while those oriented at a 45-degree angle are pinkish-red and those at 225 degrees are purplish-blue. What’s amazing is that these colors don’t involve staining or tagging the cells with fluorescent markers: the colors are generated strictly from the light interacting with the physical orientation of each neuron.

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Lighting up the Eyes

microscopic image of a network of blood vessels

Image created using a nuclear label of a flat-mount preparation of the hyaloid vessels from the eye.
Source: Richard Lang, Cincinnati Children’s Hospital Medical Center, OH

This image may conjure up thoughts of bioluminescent jellyfish, but it actually shows a network of developing blood vessels in the eye of a three day old mouse. A study in Nature last week determined that light regulates the pattern of mouse blood vessels as they develop. Observing the intermediate states of eye development is important because abnormal blood vessel development is a major cause of blindness in premature infants.

Funded by National Eye Institute, NIH.