Figure 6
Group data for the effects of sleep-wake state on the tongue motor responses elicited by photostimulation. Group mean (+SEM) data are shown for Protocol 3 – Power (1, 2, 3, 5, 10, 15 and 20 mW). (a–c) These data illustrate the effect of stimulation power on peak elicited tongue muscle activity as a function of applied pulse number in the ChAT-ChR2(H134R)-EYFP mice. (a) responses to the first stimulation pulse (i.e., before desensitization), (b) responses from the third to fifth and last pulse (i.e., after desensitization) and (c) pooled for all pulses (i.e., irrespective of desensitization). The symbol ‘*’ indicates when the response becomes statistically significant in each sleep-wake state compared to the lowest applied power (i.e., 1 mW). Note that response thresholds are consistently lowest in REM sleep compared to non-REM sleep and wakefulness. The symbol ‘#’ indicates when responses at any given power are significantly reduced in REM sleep compared to non-REM and wakefulness. The symbol ‘$’ indicates when responses at any given power are significantly reduced in REM sleep compared to wakefulness only. (d) Tongue muscle activity during application of the same interventions in the wild-type mice lacking the opsins (n = 3 for all data points except for n = 2 for 1–3 mW). Note that the prevailing baseline tongue muscle activity is significantly higher in wakefulness compared to non-REM and REM sleep across the range (indicated by the symbol ‘#’) but that there is no effect of changes in power in the wild-type mice, i.e., the differences are due to ongoing sleep-wake state per se and not the optical interventions. (e) Box and whisker plots showing the individual and group data (i.e., median, mean (thicker line), 25th and 75th percentiles) for the slopes of the regressions of output motor responses to the magnitude of input photostimulation powers in the ChAT-ChR2(H134R)-EYFP mice. The data are derived from the output motor responses pooled for all pulses (i.e., irrespective of opsin desensitization, panel c). Individual points derive from individual mice in each sleep-wake state. The symbol ‘*’ indicates significant reductions in REM sleep compared to both non-REM sleep and wakefulness.
