Robert Gonzalez in io9:
Today we are closer than ever to understanding the biological basis of human thought. In a major first for neuroscience, researchers have produced an image showing almost an entire vertebrate brain at work — down to the level of individual neurons. Soon we'll have a human brain “activity map” which reveals how electrical impulses in the brain correlate to thought patterns, biological processes, and more.
The neurons in question belong to a zebrafish embryo, and the researchers come from HHMI's Janelia Farm Research Campus. In the video up top, the activity of individual neurons appear as flashes, detonating across the fish's entire larval brain. And while the brain of a zebrafish only contains about 100,000 neurons (compared to the tens of billions in the human brain), it represents an important step along the path to creating a Brain Activity Map for us apes, a project into which the Obama administration may soon funnel billions of dollars.
According to findings published in the latest issue of Nature Methods, microscopist Phillip Keller and neurobiologist Misha Ahrens have modified an existing imaging technique (called light sheet microscopy) in such a way that enables them to record neuronal activity from the entire volume of the zebrafish's brain. They did this while the embryo was alive, and with a temporal resolution of 0.8 Hz (meaning they were recording activity about once every second). All told, Keller and Ahrens were able to capture “more than 80% of all neurons at single-cell resolution.“