Figure 6.

Initial SCN response to LD phase shift is loss of rhythmicity in VIP neurons, then a shift to the new phase precedes the shift of behavioral rhythms. (A) Recording clock gene expression in vivo from the SCN during an 8 h advance of the LD cycle. Light treatments are indicated by bars on top of the recordings. SCN VIP neurons are expressing a reporter for Per2 (example shown in blue) or Cry 1 (red lines) during 17 days. The phase shifts of SCN VIP neurons (B) or wheel-running behavior (C) are summarized. Running wheels were present in the experiments reported in (C) but not for the data in (B) [27].