Neural Circuits Underlying Circadian Oscillations in Mammals: Clocks in a Dish

In mammals, the part of the nervous system responsible for most circadian behavior can be localized to a bilaterally paired structure in the hypothalamus known as the suprachiasmatic nucleus (SCN). Understanding this mammalian circadian system will require a detailed multilevel analysis of neural SCN circuits. Many of the techniques and approaches that are used for the analysis of the circuitry driving circadian oscillations in the SCN are similar to those employed in other brain regions. There is, however, one fundamental difference that needs to be taken into consideration, that is, the physiological, cellular, and molecular properties of SCN neurons vary with the time of day. These cells continue to oscillate in the dish, so the daily circadian cycle always needs to be a consideration regardless of the experimental preparation. In this chapter, we will consider the preparations and techniques that we have used to analyze the SCN circuit including acute brain slice, slice culture, and disassociated neurons.