Sara Reardon, reporter
It looks like fireworks in a zebrafish brain: this video shows the first live images of 80 per cent of a living vertebrate's brain activity. The flashing display could help explain how different parts of the brain work together to control the animal's behaviour.
Leading neuroscientists in the US are now focussed on understanding how the brain works through the Brain Activity Map (BAM) project, but it's difficult to peer deeply enough into a brain to map the activity of every neuron. Because zebrafish embryos are transparent, the task is easier.Misha Ahrens and Philipp Keller from the Howard Hughes Medical Institute in Ashburn, Virginia, used a novel microscopy technique and a super-fast camera to capture the flashes of zebrafish neurons firing. They were able to take a picture of a fish's entire brain every 1.3 seconds, the fastest functional imaging speed ever recorded.
Previous techniques could show the activity of only about 1000 neurons at a time. "What you can do now is see how tens of thousands of neurons represent the outside world and how they control behaviour," says Ahrens. By subjecting a zebrafish to odours, chemicals or visual images, they will be able to see how its brain interprets and responds to different stimuli.
According to Rafael Yuste of Columbia University in New York, one of the lead investigators for BAM, it's a phenomenal piece of work. But it will be some time before the technique is useful for anything but transparent zebrafish embryos. To see the brain of a mouse, for example, the skull would have to be removed and even so it would be tricky to image deep structures.
If you enjoyed this post, watch the first brain movie of a mouse thinking or see the first MRI videos that capture the fetal brain connecting up.