Fig. 9.4.

Discharge of an Orx neuron across sleep–wake states. Record of a neuron labeled by juxtacellular technique with Neurobiotin (Nb) and identified by immunohistochemistry for Orx in the rat. As evident in 10-second traces (above), the unit fired during wakefulness (A) and was virtually silent during slow-wave sleep (B), transition to paradoxical sleep (C), and paradoxical sleep (D). As evident in an expanded trace (of approximately 4 seconds, below), the unit discharged during active wake (aW) and increased firing phasically in association with increases in muscle tone seen on the EMG. aW, active wake; EEG, electroencephalogram; EMG. electromyogram; PF, prefrontal cortex; PS, paradoxical sleep; RS, retrosplenial cortex; SWS, slow-wave sleep; tPS, transition to paradoxical sleep; W, wake.

Horizontal scale bars: 1 second. Vertical scale bar: 1 mV for EEG, 0.5 mV for EMG, and 2 mV for unit. (Reprinted with permission from Lee et al. (2005a).