Figure 6: Photostimulation-induced grooming is sensitive to the context.
From: Hypothalamic CRH neurons orchestrate complex behaviours after stress
(a–h) Identical light delivery protocol (10 hz for 5 min) used in novel environment (Novel) and in the FS immediately after footshock stress. (a–c) Photostimulation of PVN CRH neurons in Novel. (a) Each row represents an individual animal. (b) Histogram showing percentage of animals grooming. (c) Quantification of grooming in Novel (CRHeYFP: 8.9±1.2 s, n=10; versus CRHChR2: 85.0±10.9 s, n=10; P<0.0001; t-test). (d–f) Optical stimulation of PVN CRH neurons in FS. (d) Each row represents an individual animal. (e) Histogram showing percentage of animals grooming. (f) Quantification of grooming in FS (CRHeYFP: 6.4±2.5 s, n=10; versus CRHChR2: 40.1±9.5 s, n=10; P=0.0031; t-test). (g) Cumulative graphs illustrate the relative effect of different contexts on optically evoked grooming including habituated (HAB) context (data shown in Fig. 3). (h) Optically evoked grooming time is gradually attenuated as the presumptive threat level of the context increases (Novel: 74.7±7.9% of HAB, P=0.0405 versus HAB; FS: 35.8±8.3% of HAB, P=0.0013 versus HAB, P=0.0006 versus Novel; n=10; repeated-measures one-way ANOVA). (i) Schematic of experiment showing effects of habituation on ChR2-induced grooming. (j) Increased familiarity in the paradigm causes a decrease in baseline locomotion distance in the arena in the non-HAB (day 5: 45.79±10.78% of day 1, n=11; P=0.0004 versus day 1; paired t-test), but not in the HAB animals (day 5: 85.13±10.62% of day 1, n=5; P=0.21 versus day 1, paired t-test; P=0.0431 versus non-HAB, t-test). (k) Optically evoked grooming time is higher on the fifth day in non-HAB mice (day 5: 189.6±27.8% compared with the day 1, n=11; P=0.0016; paired t-test). In contrast, HAB animals show invariant response to optical activation (day 5: 88.5±7.7% compared with day 1; n=5, P=0.323 versus day1, paired t-test; P=0.0316 versus Non-HAB, t-test). Scale bars: (b,e,g), 20%; *P<0.05; **P<0.01; ***P<0.0005; ****P<0.0001. Error bars±s.e.m.
