Laser Cell Ablation in Intact Drosophila Larvae Reveals Synaptic Competition

We are trying to understand the mechanisms underlying neural circuit assembly during development, and we use simple nervous systems like drosophila to study this question. One of these mechanisms is the role of synaptic competition in circuit assembly, and the present paper is focused on this issue. One exciting new technology in neuroscience is called optogenetics.

It uses light sensitive ion channels to turn neurons on or off using light pulses. These new methods allow us to control neural circuitry in new ways and link the circuits to behavior. Ablation of a single neuron in the living animal has allowed us to characterize the role of competition in the assembly of simple neural circuits.

Now we can screen for the molecular machinery that underlies this widespread phenomenon. We demonstrate a competitive interaction between the two giant neurons for synaptic contact with their target motor neurons. This result has paralleled throughout the animal kingdom, especially in the vertebrate visual system where it was first discovered.

This paves the way for investigating the molecules that regulate this competition in a genetically tractable organism like drosophila. We will use this new method of optogenetics to enhance our understanding of the neural circuit underlying the escape behavior. We will also use our understanding of the neural circuit to better understand how these new optogenetic tools work.