The brain continuously integrates multiple sensory inputs and, in combination with evoked memories of past events, choses a single behavioural response to the exclusion of all other possible responses. Brain circuits communicate with motor circuits in the spinal cord via descending neurons. While spinal motor circuits can operate autonomously, descending inputs from the brain can modulate their activity and alter the choice of motor program. Neurons whose activation elicits a specific motor program, while simultaneously suppressing other motor programs, have been generally referred to as command neurons. The activity of a command neuron can act as a surrogate signal for the execution of the motor program they elicit, allowing the experimenter to focus on the circuits upstream while using the activity of command neurons as a circuit readout. In this project, you will investigate with optophysiology, electrophysiology and modelling how circuits upstream of command neurons operate towards eliciting a particular motor program to the exclusion of others. At your disposal are the whole 3,000-neuron synapse-level wiring diagram of the larval Drosophila brain, together with thousands of single-cell type specific genetic driver lines to monitor and control the activity of neurons in this brain. Your research will build upon a decade of studies on the structure-function relationship of neural circuits in this organism, which has proven to be an outstanding experimental powerhouse for finding out how neural circuits work.

Eschbach C, Fushiki A, Winding M, Schneider-Mizell C, Shao M, Arruda R, Eichler K, Valdes-Aleman J, Ohyama T, Thum AS, Gerber B. (2019)
Multilevel feedback architecture for adaptive regulation of learning in the insect brain.
bioRxiv. 1:649731.

Carreira-Rosario A, Zarin AA, Clark MQ, Manning L, Fetter RD, Cardona A, Doe CQ. (2018)
MDN brain descending neurons coordinately activate backward and inhibit forward locomotion.
Elife. 2;7:e38554.

Eichler K, Li F, Litwin-Kumar A, Park Y, Andrade I, Schneider-Mizell CM, Saumweber T, Huser A, Eschbach C, Gerber B, Fetter RD. (2017)
The complete connectome of a learning and memory centre in an insect brain.
Nature. 548(7666):175.

Takagi S, Cocanougher BT, Niki S, Miyamoto D, Kohsaka H, Kazama H, Fetter RD, Truman JW, Zlatic M, Cardona A, Nose A. (2017)
Divergent connectivity of homologous command-like neurons mediates segment-specific touch responses in Drosophila.
Neuron. 96(6):1373-87.

Jovanic T, Schneider-Mizell CM, Shao M, Masson JB, Denisov G, Fetter RD, Mensh BD, Truman JW, Cardona A, Zlatic M. (2016)
Competitive disinhibition mediates behavioral choice and sequences in Drosophila.
Cell. 167(3):858-70.