New technique IDs odor-related neurons

COURTESY OF ANDRE FIALA AND THOMAS RIEMENSPERGER

Using light to activate specific brain cells that release chemicals implicated in positive or negative experiences, Andr￢ Fiala and colleagues at the University of Wrzburg identified neurons that are responsible for assigning value to a neutral odor in the Drosophila. ¹ "It is a very elegant study revealing both impressive technical and scientific findings," says Faculty of 1000 member Martin Giurfa of the National Center for Scientific Research and the University of Toulouse in France.

"The first point is the technical event. They put light-activated ion channels in the Drosophila larvae that open or close depending on the presence of light. It is a fantastic procedure because it is a noninvasive method - they do not catch or touch the larvae. They produce the sensation that there is something bad or good by activating dopaminergic neurons, which represent an aversive stimulus like salt punishment, or octopaminergic neurons, which represent a positive stimulus like fructose reward. The scientific significance is that they show for the first time that simultaneously in the same individual, [octopamine and dopamine] are necessary and sufficient to mediate the two different kinds of rewards. It would be very nice to know whether the same thing applies in other species, like bees, but we currently do not have a protocol for aversive learning in honeybees. We need to develop a particular lab tool to show that this is a general principle."