Less than ten miles from Hollywood's theaters, which turning just about every new blockbuster into a 3D sensation, 3D vision is the fad of another venue: the lab. Scientists at UCLA have designed a microscope that can record the three-dimensional, lightning-fast patterns of neurons firing in a live brain.
The new imaging scope partially uses an old trick familiar to laser-scanning aficianados: two-photon laser-scanning microscopy. Simply put, a laser excites electrons in fluorescent dyes that have been previously added to neurons in the brain. Once excited, the dyes give off detectable photons, that is, particles of light. But then the researchers found a way to split the main laser beam into four “beamlets,” meaning they could record four times as many neuron firing than with one beam. And the four beams could each be set to penetrate a different depth into the tissue — hence a picture with dimension.
The technique is called STEM, “spatio-temportal excitation-emission multiplexing,” and it allows a microscope to image neurons like this one:
Many mental disorders including schizophrenia and autism are thought to be due to the miscommunication of neurons. But “seeing” brain activity — especially in vivo and in real time — could take some of the guesswork out what's going on in the brain.
As one researcher says in the UCLA press release, the new microscope captures images nearly ten times faster than a video camera, a view with fine detail. Already, some scientists have been able to spot the difference between a normal mouse brain and one with a form of autism, called Fragile X syndrome.