Fig. 1.

Awake, sleeping, and feeding States. A: behavioral protocol and associated local field potentials (LFPs) in awake and sleeping states as well as during feeding (licking). Top, after a 20-min habituation period, food (chocolate-flavored Ensure) was made available ad libitum. Middle, color-coded diagram shows the hypnogram and occurrence of various behavioral states the rat experienced during the experiment: blue, awake; red, feeding (licking); gray, slow-wave sleep (SWS). The awake state produces low-amplitude fast oscillations in the LFP (see left inset trace below). At the macrostructure level, it can be seen that the animal ate 2 large meals. Middle inset displays 20 s of the licking microstructure; shown are 5 licking clusters and the corresponding inter-cluster intervals (ICIs). As the SWS state deepens, delta waves in the LFP largely predominate (see right inset). In insets, bars = 1 s. B: normalized inter-lick interval (ILI) distribution (red line). For visualization purposes, the abscissa only shows up to 1-s interval. The cumulative density function (CDF) is shown as a black line. C: schematic of microarray in the medial ventral striatum where the electrodes were implanted. NAc, nucleus accumbens.