Figure 5.

An endogenous glutamatergic drive onto trigeminal motoneurons is functional during wakefulness and REM sleep. A, A typical example showing that antagonism of non-NMDA and NDMA receptors on trigeminal motoneurons in the left motor pool reduces basal tone of left masseter muscle during alert waking; this intervention also abolishes the muscle twitches of phasic REM sleep. B, Group data demonstrating that application of CNQX and d-AP-5 caused a significant reduction in left masseter activity during alert and quiet waking but had no affect on basal masseter tone during either NREM or tonic REM sleep. C, D, Antagonism of non-NDMA and NMDA receptors decreased the number of muscle twitches in the left masseter muscle during phasic REM sleep and decreased the amplitude of the remaining muscle twitches. All values are means ± SEM; *p < 0.05 and **p < 0.001; A.U., arbitrary units.