演者：Dr. Satchidananda Panda
Salk Institute for Biological Studies La Jolla, California, USA
演題：Balance between phase shift and coupling among the SCN neurons determines adaptation to ambient light dark condition.
Coupling among cell autonomous circadian oscillator neurons ensures robust rhythm in rest-activity that is relatively resistant
to abrupt change in ambient light. The master regulator for such intercellular coupling is unknown. We took a genomic approach
to find coupling mechanism with the hypothesis that light induced phase shift weakens coupling among SCN neurons and makes them
labile to phase shift. We found that phase-shifting pulse of light transiently down-regulates Lhx1 expression in the SCN and its
target coupling factors. Mice with reduced expression of Lhx1 in the oscillator neurons of the Suprachiasmatic nucleus have intact
cell autonomous oscillators, but weakened coupling. This renders the mice susceptible to large phase shifts with change in ambient
light and under constant darkness the activity-rest cycle dampens to arrhythmicity.
世話人：理学系研究科 深田 吉孝