Fig. 6.

Diversity of GPCR expression among clock neurons as a mechanism for tuning physiology and behavior. The clock neuron network expresses RNAs for ∼two-thirds of all GPCRs encoded by the fly genome. This allows the network to constantly assess the outside environment as well as the state of other networks in the brain that can then signal to the clock center. These signals can then alter the physiology of the clock and lead to changes in clock-controlled output.