TY - JOUR T1 - Discharge and Role of Acetylcholine Pontomesencephalic Neurons in Cortical Activity and Sleep-Wake States Examined by Optogenetics and Juxtacellular Recording in Mice JF - eneuro JO - eNeuro DO - 10.1523/ENEURO.0270-18.2018 SP - ENEURO.0270-18.2018 AU - Youssouf Cissé AU - Hanieh Toossi AU - Masaru Ishibashi AU - Lynda Mainville AU - Christopher S. Leonard AU - Antoine Adamantidis AU - Barbara E. Jones Y1 - 2018/08/31 UR - http://www.eneuro.org/content/early/2018/08/31/ENEURO.0270-18.2018.abstract N2 - Acetylcholine (ACh) neurons in the pontomesencephalic tegmentum (PMT) are thought to play an important role in promoting cortical activation with waking and paradoxical (or REM) sleep (PS), but have yet to be proven to do so by selective stimulation and simultaneous recording of identified ACh neurons. Here, we employed optogenetics combined with juxtacellular recording and labeling of neurons in transgenic mice expressing ChR2 in choline acetyltransferase (ChAT)-synthesizing neurons. We established in vitro then in vivo in anesthetized and unanesthetized, head-fixed mice that photostimulation elicited a spike with short latency in neurons which could be identified by immunohistochemical staining as ACh neurons within the laterodorsal/sublaterodorsal and pedunculopontine tegmental nuclei (LDT/SubLDT and PPT). Continuous light pulse stimulation during sleep evoked tonic spiking by ACh neurons that elicited a shift from irregular slow wave activity to rhythmic theta and enhanced gamma activity on the cortex without behavioral arousal. With theta frequency rhythmic light pulse stimulation, ACh neurons discharged in bursts that occurred in synchrony with evoked cortical theta. During natural sleep-wake states, they were virtually silent during slow wave sleep (SWS), discharged in bursts during PS and discharged tonically during waking (W). Yet, their bursting during PS was not rhythmic or synchronized with cortical theta, but associated with phasic whisker movements. We conclude that ACh PMT neurons promote theta and gamma cortical activity during W and PS by their tonic or phasic discharge through release of ACh onto local neurons within the PMT and/or more distant targets in the hypothalamus and thalamus.Significance Statement By selectively stimulating and recording acetylcholine (ACh) neurons in the pontomesencephalic tegmentum (PMT), we show that evoked tonic or theta rhythmic phasic firing by ACh neurons attenuates slow wave activity and stimulates theta and gamma activity on the cerebral cortex without eliciting behavioral arousal from sleep. During natural sleeping-waking, ACh neurons are virtually silent during slow wave sleep (SWS), discharge in bursts during paradoxical or REM sleep (PS) and discharge in a tonic manner during waking (W). We conclude that by tonic or burst discharge during W and PS, ACh PMT neurons promote theta with gamma activities that are known to be important for memory along with other cortical processes during these states. ER -