Endogenous Pacemakers and Exogenous Zeitgebers 1

Suprachiasmatic nucelus (SCN)

- Tiny bundle of nerve cells in hypothalamus

- Primary endogenous pacemaker (maintains sleep/wake cycle)

- SCN lies above the optic chiasm

- It recieves information about light eve when our eyes are closed

Animal studies and the SCN

- DeCoursey

- Destoyed SCN connections in brains of 30 chipmunks

- They were returned…