News item

FlyMAD: from a “crazy idea” to a functional method

At the Vienna Biocenter “crazy ideas” materialize! Dan Bath, a VBC PhD Student in Barry Dickson’s Lab wants to understand the integration of excitatory and inhibitory information in the central brain. To address this question he needed to quickly activate inhibitory neurons in freely-moving animals. Dan teamed up with Andrew Straw´s team to create a tool for rapid manipulation of neurons in freely-moving flies: FlyMAD (the Fly Mind Altering Device).

Dan Bath

Rapid control of neuronal activity in freely walking Drosophila

Life Science are mostly driven by curiosity; nevertheless some of the most exciting results are technological developments that help elucidate longstanding scientific questions - frequently the existence of the right tools/technologies is the bottleneck for the advancement in science. This week in Nature Methods a team of IMP scientists describes an important tool for studying the neuronal circuits in Drosophila - FlyMAD. 

But so what is FlyMAD?  FlyMAD (the Fly Mind Altering Device) is a tool for the rapid manipulation of neurons in freely-moving flies: it uses computer vision to target an infrared laser on freely-walking flies. Or as I see it - from a non-specialist perspective - it is a cool and ingenious combination of mirrors, cameras and lasers which manipulate neurons in freely-moving animals within seconds.  Before FlyMAD, the ability to turn neurons on and off during freely-moving animals with thermogenetics was limited to very slow timescales, usually several minutes. With FlyMAD, the authors improved those timescales to fractions of a second.  This is an extremely powerful and versatile tool as it enables fast thermogenetic and optogenetic modulation of neuronal activity in freely-walking flies, and we are sure that it will allow many more functional insights into neuronal circuits in Drosophila. 

One of the protagonists of the FlyMAD device is VBC PhD Student Dan Bath (co-first author).  Dan studied at the University of Western Ontario (Canada) where he completed a Masters in Biology. Afterwards he was interested in Barry Dickson’s work on courtship behavior in flies, and so he applied to the VBC PhD programme.  Dan started his PhD in the Dickson Lab (formerly at the IMP, the lab moved to HHMI Janelia Farm Research Campus last fall), with the aim of understanding how the integration of excitatory and inhibitory information in the central brain leads to observed behaviors (using the Drosophila courtship as a model system). To write this piece I went to our archive and looked at Dan’s application to the PhD Programme - funny enough even in 2010 his research interests were exactly what he set out to do during his PhD.

Dan started his PhD project at the VBC in early 2011, and quickly realized that: “In order to fully understand inhibition, I needed to quickly activate inhibitory neurons during ongoing courtship. The previous standards for neuronal activation did not measure up to these requirements. Thanks to FlyMAD's rapid, dual activation or silencing of neurons, I am able to tackle an intriguing biological question in exciting new ways”.  

Fortunately for Dan in the neighboring lab at IMP, Andrew Straw and his team work on Neural circuits for vision, and in parallel focus on engineering tools for quantitative behavior.

“Coming from a background in biology, the technical requirements of establishing the method were far beyond my capabilities. Through collaboration with Andrew Straw's lab, in particular John Stowers (co-first author), we managed to bring FlyMAD from a crazy idea to a functional method that surpassed our original goals. Without our complementary skills, the project would never have been a success”, says Dan.

The multidisciplinary scientific environment at the VBC has supported yet another successful collaboration between labs with complementary expertise; furthermore the core facilities were instrumental for the technical design and manufacturing of this new technology.

Congrats to the FlyMAD Team and keep up the excellent work!


Bath DE, Stowers JR, Hörmann D, Poehlmann A, Dickson BJ, Straw AD (2014) FlyMAD: rapid thermogenetic control of neuronal activity in freely walking Drosophila. Nat Methods, Available online 25 May 2014, Opens external link in new windowdoi: 10.1038/nmeth.2973