Video: Mini microscope

A small microscope that can be mounted on an animal’s head should offer a front-row view of how its brain processes visual and other stimuli on the move.

A laser inside the device scans the activity of neurons through a tiny hole in the skull, made prior to the experiment under anaesthetic. When the microscope was attached to freely moving rats looking at screens, it produced images of brain cells that had been labelled with a fluorescent dye.

Compared with previous methods – which require restraining animals and inserting electrodes – this technique is much less invasive, revealing brain activity in animals that are moving and interacting with their environment in a more natural way. It was developed at the Max Planck Institute for Biological Cybernetics in Tübingen, Germany.

Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0903680106