Assembling a Multi-Cellular CircadianPacemaker

Description and Aim

Nearly all organisms possess an endogenous circadian clock that regulates biological processes in the temporal domain.  This clock governs a wide array of rhythms, from biosynthetic to behavioral, and synchronizes (entrains) them to the 24-h environmental day-night cycle.  The discovery, characterization, and even manipulation of oscillating “circadian clock” genes during the last several years has been an indisputable triumph in our search for the genetic basis of animal behavior.  While we now know that the basic circadian oscillatory mechanism is intracellular, we still don’t understand how these molecular clockworks gain expression beyond the cell, to be translated into the adaptable temporal programs that are manifested by whole organisms.  In fact, behavioral rhythms in insects and mammals appear to be the product of complex brain pacemakers that are composed of multiple individual cellular circadian oscillators coupled together in neuronal networks.

In large part, the elucidation of molecular clocks was catalyzed by the fantastic cross-talk between researchers working on insects, especially fruitflies, and mice.  We believe that the time is now ripe to actively foster a similar collaboration at the neural circuit level of analysis.  New experimental techniques, results, and computational approaches now make such a proposed interface especially timely.  This workshop seeks to promote a new dialogue by bringing together senior and junior scientists working on this problem in an informal but intensive way.  Among the kinds of questions to be tackled are: How do photoresponsive cells reset endogenously rhythmic cells in the network?  How is the complex pacemaker reconfigured by photic input?  How are the activities of multiple cells integrated to create a coherent output signal? and more. 

Participants will engage in a number of activities, including a series of "class sessions" that pose questions for the workshop at large, "discussion groups" and "discussion group reports" to address the questions, and additional special sessions, including "hot topic" presentations and a "tutorial" on mathematical theory and modeling of neural networks.