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Mapping the Mind: Online Interactive Atlas Shows Activity of 20,000 Brain-Related Genes

A meticulously constructed atlas of the human brain reveals the molecular roots of mental illness—and of everyday behavior
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THE HUMAN BRAIN IN 3-D

In another screenshot to be included in a later iteration of the atlas, a single 3-D view merges structural MRI scans with other imaging data showing the locations of the nerve fiber tracts. Colors separate different subdivisions of the brain’s cerebral cortex, its outermost section.....[ More ]

TRACTS OF THOUGHT

Here, a 3-D rendering of the brain shows the major tracts of nerve fibers spanning its interior, with the colors denoting the directions in which they run: blue fibers run top-to-bottom, red side-to-side and green front-to-back.....[ More ]

MAPPING A MOLECULE FOR MOVEMENT

In this screenshot from the Allen Brain Atlas, spots overlaying three MRI snapshots of the brain denote the activity of a gene called ADORA2a implicated in movement disorders such as Huntington’s and Parkinson’s diseases.....[ More ]

CONSTELLATION OF GENES

This image from a gene chip shows the activity of thousands of genes from tissue taken from a section of the hippocampus. Each spot denotes activity from a separate, single gene; the brighter the spot, the more active that gene is in the tissue sample tested.....[ More ]

GENE CHIPS AT WORK

To assess gene expression in each small bit of tissue, researchers expose its RNA to a gene chip, or DNA microarray. These small devices are coated with clusters of identical DNA molecules, called probes, within separate areas.....[ More ]

LASER DISSECTION

Researchers view each hair-thin wafer of brain tissue under a microscope outfitted with a laser for precision dissection. The laser cuts short ribbons of tissue about one-millimeter across. Note the white “holes” in this slice from the brain’s hippocampus, a structure involved in memory.....[ More ]

REVEALING ANATOMY

Anatomists cut each solidified brain slice into blocks small enough to fit onto a 2 X 3-inch microscope slide, making incisions that skirt key brain structures ( left ). Staining of a thin sliver of each block can highlight the main bodies of nerve cells ( top, purplish image ) with the darker areas indicating high cell density near the brain’s surface.....[ More ]

BEEFING UP THE BRAIN

A scientist pours a solidifying substance onto the frozen brain ( left ), so that it maintains its shape and can be easily divided into smaller sections. Removing a layer of white residue smoothes the surface of the slab and reveals its internal anatomy ( right ).....[ More ]

SLICED AND FROZEN

Technicians slice the brain as if it were a loaf of bread into slabs up to about a centimeter thick. They place each slab onto a plate that sits on a slurry of dry ice, freezing the neural tissue to preserve it.....[ More ]

STRIPPING OFF SCAFFOLDING

In the first phase of construction, laboratory workers remove the thin, sturdy membrane, embedded with a net of blood vessels, that encases the brain. Stripping the cerebrum of this protective layer allows the brain to be sliced more evenly.....[ More ]

UNCHARTED TERRITORY

Through this web portal, researchers can enter an intricate molecular landscape in which the active genes dot each hill and valley of the human brain. The interactive atlas, called the Allen Human Brain Atlas, is designed to greatly speed scientists’ discovery of the molecular underpinnings of mental illness as well as the intricacies of ordinary human thought and behavior.....[ More ]

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