快猫短视频

FOR the first time it is possible to watch as nerve cells start firing in synchrony 鈥� an activity thought to be the key to many brain processes.

鈥淭his is a totally new way of looking at the brain,鈥� says Frank Moss, director of the Center for Neurodynamics at the University of Missouri at St Louis. 鈥淚n my mind, it鈥檚 a revolutionary advance.鈥�

The well-known technique of magnetic resonance imaging measures blood flow rather than nerve activity, and takes a second or so to build up an image of the brain. An alternative technique known as magnetoencephalography measures the magnetic fields generated by the tiny electric currents flowing through active neurons. It is potentially much better for observing synchronisation, but its usefulness has been limited because it requires a vast amount of processing power to analyse results.

Now, though, Peter Tass鈥檚 team at the J眉lich Research Centre in Germany has improved the analysis software, making it possible to build up images of synchronisation with millisecond resolution, the timescale on which neurons actually operate (Physical Review Letters, DOI: 088101-1).

The group used the technique to study a task called paced finger tapping in which subjects are asked to continue tapping their finger in time to a beat after the sound is turned off. During the task, the sensory motor cortex controls the finger, the cerebellum works on timing and the secondary auditory cortex creates the brain鈥檚 inner voice. 鈥淲hat鈥檚 surprising is that when the subject switches to the inner voice for timing, all these areas become synchronised,鈥� says Tass. 鈥淭hat鈥檚 never been seen before.鈥�

And synchrony sometimes goes wrong. The characteristic tremors of Parkinson鈥檚 disease may be caused by parts of the brain that should behave independently somehow becoming locked in step. Tass hopes the imaging technique will help him work out how to break unwanted synchronisation.