PMC

The graph shows changes relative to the baseline values (week 0) after a 6 weeks and b 18 weeks of dietary intervention. *Statistically significant at alpha < 0.05. ∑All: sum of all BA; ∑Prim: sum of primary BA; ∑Sec: sum of secondary BA; ∑Tert: sum of tertiary BA; 12-α: 12-α hydroxyl BA; non 12-α: non 12-α hydroxylated BA; 12-α/non 12-α: ratio of 12-α hydroxyl BA to non 12-α hydroxylated BA; Conj: conjugated BA; Unconj: unconjugated BA; Conj/Unconj: ratio of conjugated to unconjugated BA

(A-D) Cre-dependent ChR2 injection into DRN and unilateral optrode array implantation into BA of 5-HTT-Cre mice (A). ChR2 expression in DRN (B). ChR2 expression in DRN 5-HT projections in BA (sagittal); dashed red lines=optical fibre tract (C). Bright field image of optrode array placement in BA (sagittal) (D). Scale bars=500 μm.
(E) Raster plot of a BA single unit firing during CS pips in early FE.
(F1) Top: Behavioural task. 20 Hz laser stimulation was delivered during FC CSs. In vivo electrophysiology data from FC. Bottom: No difference in proportion of BA single unit responses to CS pips (YFP n=53 units, 9 mice; ChR2 n=58 units, 9 mice).
(F2) Firing rates of BA single units were lower in ChR2 vs. YFP mice during CS pips (YFP n=53 units, 9 mice; ChR2 n=58 units, 9 mice). Traces show mean±SEM of z-scored firing rate. Dashed lines at +2.58 demarcate statistically significant change from baseline (2-tailed, α=0.01).
(G1) Top: Behavioural task. 20 Hz laser stimulation was delivered during FC CSs. In vivo electrophysiology data from early FE (CS1–5). Bottom: A greater proportion of BA single units was excited during CS pips in ChR2 vs. YFP mice (YFP n=97 units, 9 mice; ChR2 n=68 units, 8 mice).
(G2) Firing rates of BA single units in ChR2 and YFP mice increased during CS pips (YFP n=97 units, 9 mice; ChR2 n=68 units, 8 mice). Traces show mean±SEM of z-scored firing rate. Dashed lines at ±2.58 demarcate statistically significant change from baseline (2-tailed, α=0.01).
(H1) Top: Behavioural task. 20 Hz laser stimulation was delivered during FC CSs. In vivo electrophysiology data is from early FE (CS1–5). Bottom: No difference in proportion of BA single unit firing during freezing onset (YFP n=71 units, 9 mice; ChR2 n=61 units, 8 mice).
(H2) Firing rates of BA single units were higher overall in ChR2 vs. YFP mice during freezing onset (YFP n=71 units, 9 mice; ChR2 n=61 units, 8 mice). Traces show mean±SEM of z-scored firing rate. ±1.96 represents statistically significant change from baseline (2-tailed, α=0.05).
(I1) Top: Behavioural task. 20 Hz laser stimulation was delivered during FC CSs. In vivo electrophysiology data from ER. Bottom: No difference in proportion of BA single unit responses to CS pips (YFP n=96 units, 9 mice; ChR2 n=64 units, 9 mice).
(I2) Firing rates of BA single units were higher in ChR2 vs. YFP mice during CS pips (YFP n=96 units, 9 mice; ChR2 n=64 units, 9 mice). Traces show mean±SEM of z-scored firing rate. Dashed lines at +2.58 demarcate statistically significant change from baseline (2-tailed, α=0.01).
*p<0.05, ***p<0.001.
See also and .

: a Control at 6 weeks (ow/ob: n = 10/10). b Control at 18 weeks (ow/ob: n = 10/10). c High cereal fiber (HCF) at 6 weeks (ow/ob: n = 5/10). d HCF at 18 weeks (ow/ob: n = 5/10). e High protein (HP) at 6 weeks (ow/ob: n = 6/12); f HP at 18 weeks (ow/ob: n = 6/12). g Mixed-diet (MIX) group at 6 weeks (ow/ob: n = 8/11). h MIX at 18 weeks (ow/ob: n = 8/11). Black bars: overweight; white bars: obese. *Statistically significant at alpha < 0.05. ∑All: sum of all BA; ∑Prim: sum of primary BA; ∑Sec: sum of secondary BA; ∑Tert: sum of tertiary BA; 12-α: 12-α hydroxyl BA; non 12-α: non 12-α hydroxylated BA; 12-α/non 12-α: ratio of 12-α hydroxyl BA to non 12-α hydroxylated BA; Conj: conjugated BA; Unconj: unconjugated BA; Conj/Unconj: ratio of conjugated to unconjugated BA

(A) Histological reconstructions of the trajectory of the recording sites (bars) in the dHPC and the BA. (B) The number of simultaneously recorded cells during each recording day. The gray shaded area represents 2 days where cells were recorded from only one region. (C) A detailed composition of the significant pairs: the actual number of dHPC and BA cells and the number of overlapped pairs/cells between epochs. (D) Cross-correlograms (CCs) of all BA-dHPC cell pairs (n = 99) that showed significant spike synchrony during the pre-pellet epoch (left) but not during the post-pellet (middle) and pre-surge (right) epochs (10 ms bin). The red dashed rectangles indicate the time window for statistical significance, –100 ms to +100 ms from the BA spikes. The vertical lines (0) indicate the time when the reference BA spikes occurred. The horizontal lines indicate the borders between the presumed dHPC→BA pairs (above the line) and BA→dHPC pairs (below the line). (E) CCs of all BA-dHPC cell pairs (n = 80) that showed significant spike synchrony during the post-pellet epoch (middle) but not during the pre-pellet (left) and post-surge (right) epochs. (F) The proportions of BA-dHPC pairs that showed significant spike synchrony during the pellet procurements (pre-pellet, post-pellet; n = 146), robot encounters (pre-surge, post-surge; n = 174), or both pellet-robot (n = 29). (G) The Z-scored dHPC spikes at the time of BA spikes are shown in upper (dHPC→BA pairs, ****p<0.0001) and bottom (BA→dHPC pairs, ****p<0.0001) during the pre-surge. The dark lines represent the mean, and the shaded bands represent SEM. (H) The Z-scored dHPC spikes at the time of BA spikes are shown in upper (dHPC→BA pairs, ****p<0.0001) and bottom (BA→dHPC pairs, ****p<0.0001) during the post-surge. (I) The percentage of the dHPC→BA and BA→dHPC cell pairs in the pre-surge and post-surge peaked CCs (p=0.787).