In the complex maze of cells in the brain, identifying the function of individual neurons is a daunting task. Yet a team of researchers have recently developed a technique to facilitate this process, allowing them to turn specific cells on and off to test their effects on behaviour. Using a modified virus, they inserted a gene encoding a light-sensitive protein, channelrhodopsin-2, into the brain of adult macaques, together with a small segment of DNA, or promoter, which ensured it was activated only in Purkinje cells. Shown here in yellow, Purkinje cells are large and well-connected neurons, involved in producing coordinated movements. When activated by light through a thin optical fibre, channelrhodopsin-2 caused the Purkinje cells to fire, with measurable effects on movement. Although still in its infancy, this technique has huge potential, with a view to treating neurological disorders, such as epilepsy, by directly manipulating neuron activity.
Written by Emmanuelle Briolat
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