Figure 3.

Schematic of the single cell oscillator and the coupled SCN network. (a) The intracellular model consists of transcriptional/translational feedback loops of clock genes, modified from Bernard et al. (15). Clock genes induce the release of a neuropeptide that acts as a coupling agent. Feedback of the neuropeptide activates PKA and CREB, leading to Per/Cry mRNA transcription. (b) The individual cellular oscillators are coupled through a mean field of the released neuropeptide in the intercellular medium with a time delay to account for different phases of neuropeptide release. To see this figure in color, go online.