Fig. 2

a–h Alterations of serotonin, BDNF, CREB, and TrkB concentrations in the PFC, hippocampus following supplementation. (n = 8 per group). i and j Effect of the L. plantarum and inulin on learning and memory in the Morris water maze test. One-way ANOVA with post hoc Tukey’s test was used. Data were expressed as mean ± SD. P < 0.05 was regarded as statistically significant. D-Control diabetic control, D-Pro diabetic + the L. plantarum, D-Pre diabetic + inulin, D-Syn diabetic the L. plantarum + inulin, and D-Sham diabetic Sham group, BDNF brain-derived neurotrophic factor, TrkB tropomyosin receptor kinase B; CREB cyclic adenosine monophosphate responsive element-binding protein