Figure 4 : InsAb microinjection into the NAc shell decreases flavour preference.

From: Insulin enhances striatal dopamine release by activating cholinergic interneurons and thereby signals reward

Figure 4

(a) Diagram illustrating one-bottle conditioning (left) and the two-bottle test (right). (b) Volume consumed (ml) during one-bottle-conditioning sessions. There was a significant interaction between infusion-conditioning session and microinjection treatment (n=19–20 rats per group, F(3,111)=3.088, P<0.05, 2 × 4 mixed ANOVA with repeated measures on infusion-conditioning session). InsAb microinjection significantly decreased consumption compared with control during the third (t(40)=3.026, **P<0.01) and fourth (t(40)=3.052, **P<0.01, protected one-tailed t-tests) infusions. Mock injections had no effect on consumption in either group (F3,111=1.110, 2 × 4 mixed ANOVA with repeated measures on mock conditioning session). (c) Volume consumed during two-bottle flavour-preference test. There was a significant interaction between flavour and microinjection treatment during conditioning (F1,37=5.36, P<0.05, two-way mixed ANOVA with repeated measures on flavour). The InsAb group consumed significantly less of the InsAb-paired flavour compared with the mock-paired flavour (t(18)=2.82, **P<0.01, protected one-tailed t-test); the control group showed no flavour preference (t(19)=0.803, P>0.05, protected t-test). Comparing groups, InsAb rats drank significantly less of the infusion-paired flavour (t(40)=1.96, *P<0.05) and significantly more of the mock-paired flavour (t(40)=1.77, *P<0.05, protected one-tailed t-test) than controls.