Figure 8.

Masseter atonia in REM sleep is not mediated by concurrent glycinergic and GABAergic inhibition of trigeminal motoneurons. A, Traces showing how left masseter muscle (LM) activity changes during the transition into and out of REM sleep during baseline. B, A trace from the same rat illustrating that strychnine/bicuculline perfusion at the left trigeminal motor pool increases LM activity during the NREM and waking periods preceding and after REM onset, but that masseter atonia is unaffected by this intervention. C, An example showing the sudden loss of masseter tone on entrance into REM sleep despite strychnine/bicuculline perfusion at the trigeminal nucleus. D, Group data showing that strychnine/bicuculline perfusion increases basal LM tone in NREM and post-REM waking (QW), but not during REM sleep. A.U., Arbitrary units. All values are mean ± SEM.