The pedunculopontine nucleus (PPN) is a cholinergic area of the reticular activating system (RAS). It contributes to regulation of sleep-wakefulness cycles and movement, as it is a part of the mesencephalic locomotor region (MLR). Rostral serotonergic members of the RAS are the dorsal and median raphe nuclei (DR and MR, respectively) which also targeted by cholinergic neuromodulation and play important role in regulation of sleep-wakefulness cycles, movement and affective states. We showed that deletion of KCNQ4 leads to alterations in adaptation of activity to light-darkness cycles. Although the M-current is an electrophysiological hallmark of the cholinergic neurons, only a subpopulation of these neurons possessed KCNQ4-dependent M-current. It synchronizes neighboring PPN neurons and inhibition of the M-current decreases neuronal synchronization. Serotonergic neurons with M-current are located rostrally in the DR and dorsally in the MR. The M-current seems to have a strong impact on firing properties of certain serotonergic neuronal subpopulations and it might serve as an effective contributor to cholinergic and local serotonergic neuromodulatory actions. The MLR is a functionally-defined midbrain area consisted of the PPN and the cuneiform nucleus (CnF). We showed that CnF glutamatergic neurons are electrophysiologically more homogeneous than PPN neurons. PPN neurons composed a heterogeneous group displaying a range of adapting responses, whereas the majority of CnF neurons are fast-adapting; suggesting a greater diversity of neuronal profiles than the CnF.