A microscope the size of a matchbox is allowing US biologists to peer inside the brains of live animals. Weighing a mere 3.9 grams, the microscope has been used to image blood vessels lying 1 millimetre below the surface of the brains of anaesthetised mice, with a resolution of 1 micrometre (one-thousandth of a mm).The researchers believe they may one day be able to view brain cells in the same way. In future the tiny microscope could be strapped to the head of a conscious, moving animal and beam back a movie of the neurons while the animal engages in a variety of activities, say its creators, led by Mark Schnitzer of Stanford University, US.
