



A meticulously constructed atlas of the human brain reveals the molecular roots of mental illness—and of everyday behavior
By Allan R. Jones and Caroline C. Overly | September 2, 2010 | 7
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....[More]
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. [Less] [Link to this slide]
In the first phase of construction, laboratory workers remove the thin, sturdy membrane, embedded with a net of blood vessels, that encases the brain....[More]
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. [Less] [Link to this slide]
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]
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. [Less] [Link to this slide]
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....[More]
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). [Less] [Link to this slide]
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 )....[More]
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. A different stain marks nerve cell fibers (bottom), revealing heavy staining in the central region where nerve fiber tracts connect one region of the brain to another. Anatomists use these higher resolution images to sketch out the structural anatomy of the brain in detail. On this anatomical scaffold researchers will overlay information about gene activity—the genes a cell translates into RNA transcripts and then often protein molecules. [Less] [Link to this slide]
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....[More]
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. Each tissue ribbon is then dropped into a test tube and its RNA purified for gene expression analysis. [Less] [Link to this slide]
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]
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. Each probe binds to the RNA of a specific gene—the one that contains a complementary set of chemical units, or bases. In a DNA molecule, the base adenine (A) sticks to thymine (T), and guanine (G) pairs with cytosine (C). Thus, the sequence that would bind to the strand illustrated above is (from top to bottom): T, C, C, T, G, C, A. In this way, a chip records which genes are active, and to what extent they are active, in the tissue sample. [Less] [Link to this slide]
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]
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. [Less] [Link to this slide]
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]
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. (The adora2a protein also binds to caffeine.) The color of each spot indicates the extent to which ADORA2a is expressed in that location, with red signifying higher levels and green, lower. The red crosshairs intersect in the basal ganglia, a brain area involved in motor control and in which the gene is strongly expressed. [Less] [Link to this slide]
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]
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. (Although the nerve fiber data is already available in the online atlas, the viewing tool needed to see the brain in 3-D will appear in future versions of the atlas.) [Less] [Link to this slide]
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....[More]
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. Some nerve fiber tracts are also visible. Such images provide an important anatomical reference on which researchers can overlay information about gene expression. [Less] [Link to this slide]
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Ruled by the Body: How Physical Illness Affects the Brain
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7 Comments
Add CommentA link would be nice. O wait let me guess. You probably have to be a privileged member of academia to access this atlas ?
Reply | Report Abuse | Link to thisI still dom;t see any way to access the data.
Reply | Report Abuse | Link to thishttp://www.scientificamerican.com/article.cfm?id=mapping-the-mind
Reply | Report Abuse | Link to thispaste that in your browser and you'll be able to read the article.
http://www.scientificamerican.com/article.cfm?id=mapping-the-mind
Reply | Report Abuse | Link to thisthat will get you to the article. go for it.
The online Brain Atlas is available to all, free access, no passwords, etc, here: http://www.brain-map.org
Reply | Report Abuse | Link to thisThis is a pay article. Last time I checked SciAm isn't a welfare periodical but is run to make a profit. If you can't get that concept then you need professional help.
Reply | Report Abuse | Link to thisThe URL provided by bobnamy gets you to the Brain Atlas itself.
Thanks for the URL bobnamy. I stand corrected.
Reply | Report Abuse | Link to this