CIRCADIAN-RHYTHM IN LIGHT RESPONSE IN SUPRACHIASMATIC NUCLEUS NEURONSOF FREELY MOVING RATS

Long-term recordings of single SCN units were performed in freely movi ng rats simultaneously with multiunit recordings and evidence is prese nted for a daily change in light-responsiveness. SCN light response is high during the night and low during the day. We conclude that this d ifference is caused by a change in sensitivity, with higher sensitivit ies at night. Moreover, we demonstrate that the circadian rhythm in SC N light response is the result of the integrated behaviour of similarl y behaving single SCN units.