Bioethics Blogs

Snapshots of Life: Seeing, from Eye to Brain

Credit: Xueting Luo and Kevin Park, University of Miami

Fasten your seat belts! We’re going to fly through the brain of a mouse. Our tour guide is Kevin Park, an NIH-funded neuroscientist at the University of Miami, who has developed a unique method to visualize neurons in an intact brain. He’s going to give us a rare close-up of the retinal ganglion cells that carry information from the eye to the brain, where the light signals are decoded and translated.

To make this movie, Park has injected a fluorescent dye into the mouse eye; it is taken up by the retinal cells and traces out the nerve pathways from the optic nerve into the brain.

The ride begins just behind the eyeball and follows the optic nerve past the suprachiasmatic nucleus (which is critical for circadian rhythms) to the target destination: the superior colliculus. This region, which appears as the large bright oval, helps coordinate head and eye movements. The movie is a technical tour de force, which is why it was among the winners of the Federation of American Societies for Experimental Biology’s 2013 BioArt competition. As cool as this video is in its own right, it also provides a cutting edge tool to study connections inside the brain—without cutting it into thin slices.

Right now, you might be experiencing a little déjà vu. That’s because last year I told you about a new technique called CLARITY that could make a normally opaque brain transparent. Park has modified a tetrahydrofuron based-chemical treatment that also makes the brain (and optic nerve) transparent [1].

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.