A diffusible coupling signal from the transplanted suprachiasmatic nucleus controlling circadian locomotor rhythms

Transplanted suprachiasmatic nuclei (SCN), like neural pacemakers of silkmoths and Drosophila, restore circadian activity rhythms through a diffusible signal in animals whose own SCN have been ablated. This shows that the circadian rhythm is a result of the donor tissue rather than a consequence of spontaneous recovery of function. Re-establishment of appropriate synaptic connections and neural efferents is necessary for circadian rhythmicity.