Food intake enhances SWRs in sleep in a dose-dependent manner.

A. Experimental design: Food restricted mice were allowed to sleep during pre-sleep for 2 hours. During Meal, they received varying amounts of chow, then were allowed to sleep during Post-sleep for 2 hours. B. Snipper from an example recording session showing broadband hippocampal local field potential (LFP) (black), ripple-filtered LFP (150-250 Hz, green), ripple power (red) and detected SWRs (purple dots). C-D. The effect of chow intake on ripple power (C), ripple rate (D) and ripple duration (E). F-I. Correlations between food amount and fold change in ripple power (F, R=0.66, P < 0.001), fold change in ripple rate (G, R=0.44, P < 0.001), fold change in ripple duration (H, NS) and fold change in delta power (I, R=0.45, P < 0.001). J. Correlation between fold change in ripple power and fold change in delta power (R=0.65. P < 0.001). K. A mediation analysis, indicating that the effect of food intake on ripple power was significant after accounting for sleep-dependent effects (correlation between the changes in delta power and ripple power: B = .16, SE = .03, p < .001; the effect of meal size on the change in delta power: B = .28, SE = .07, p < .001; the indirect effect of the change in delta power mediating the relationship between meal size and ripple power: B = .04, SE = .01, p < .05, the direct effect of meal size on the change in ripple power: B = .10, SE = .02, p < .001).

Food intake enhances SWRs under ad libitum conditions.

A. Experimental design. B. Correlation between the amount of chocolate consumed and the degree of the increase in ripple power under ad libitum conditions (Nanimal = 9, Nsession = 39, R = .57, p = .0001). C-E. correlations between amount of chocolate consumed and fold change in ripple rate (C, R = 0.1, p = 0.53), ripple duration (D, R = −0.11, p = 0.1) and delta power (E, R = 0.29, p = 0.07). F. A mediation analysis showed that the effect of chocolate intake on ripple power was significant after accounting for sleep-dependent effects (the indirect effect of the change in delta power mediating the relationship between meal size and ripple power: B = .01, SE = .01, p > .05, the direct effect of meal size on the change in ripple power: B = .05, SE = .01, p < .001).

Caloric content of a meal, rather than the experience of food intake, drives the enhancement of SWRs.

A. Experimental design (Nregular = 7, Nsugar-free = 9, Nnofood = 10). B. Consumption of regular Jello resulted in a greater increase in ripple power compared to non-caloric Jello (t(14) = 2.59, p = 0.02) and the control condition (t(15) = 2.39, p = 0.03), with no significant difference between sugar-free Jello and the control condition (p = .38). C. Regular Jello consumption increased SWR rate compared to the control condition (t(15) = 2.18, p = 0.046), with no other significant differences across conditions (ps > 0.05). No differences were detected in the SWR duration or delta power across conditions (D-E, ps > .05). Red lines indicate mean, and shaded red areas indicate standard error.

Effect of systemic administration of hormones on SWR properties.

(A) Experimental design. No dose-dependent effects were detected in ripple power, rate, or duration following the administration of GLP-1 (B-C), leptin (D-E), or insulin (F) (ps > .05), except a decrease in ripple rate following insulin administration under food-restricted conditions (G, R = −0.38, p = 0.01). Ghrelin administration caused a dose-dependent decreased in SWR rate (R = −0.49, p = 0.0008) and delta power (R = −0.42, p = 0.005) under ad libitum conditions (H), and decreased ripple power (R = −0.64, p = 0.0002), ripple rate (R = −0.63, p = 0.0003), and delta power (R = −0.73, p = 0.00014) under food-restricted conditions (I). Mediation analysis revealed that ghrelin’s effect on ripple power remained significant after accounting for changes in cortical delta power under food-restricted conditions (I.i, I.ii, direct effect of ghrelin on ripple power: B = −0.25, SE = 0.11, p < 0.05).

Lateral hypothalamic GABAergic neuronal populations exhibit an increase in activity following SWRs.

A. Experimental design. B. Example recording snippet showing broadband hippocampal LFP (black), ripple-filtered LFP (150-250 Hz, green), ripple power (red), detected SWRs (purple dots), and the fiber photometry signal from LH GABAergic neurons (FP, blue). C. Example traces of LH GABAergic neuronal activity around SWRs. D. Mean trace of peri-SWR LH GABAergic activity from one session. E. Mean SWR-triggered LH GABAergic activity profiles per session. F. The mean of the SWR-triggered LH GABAergic activity profiles across sessions. G-H. Similar to E-F but for normalized traces. I. Statistical significance of LH GABAergic activity within 0.5 s before and after SWRs per session. J. Peak time of LH GABAergic activity relative to SWR onset. Shaded error bars (pink) indicate standard deviation.