Mutual coupling between the ocular circadian pacemakers of Bulla gouldiana.

The ocular circadian pacemakers of Bulla gouldiana were found to be mutually coupled, and their interaction could be observed in an isolated nervous system maintained in vitro. Experimentally induced phase separations between the two ocular pacemakers were reduced when the eyes were allowed to interact for 48 hours. The reduction in phase separation did not occur however when the cerebral commissure was severed, indicating that this neural tract is a critical pathway coupling these two circadian clocks.