Given that mAChRsare widely expressed inthe visual cortex- the predominant postsynaptic mAChR being M1 subtype and the presynaptic mAChR being M2 – and that M1 and M3 receptors are involved in hippocampal LTP, it was expected that inhibition of these receptors would abolish long-term enhancement of VEP. The present results of scopolamine administration verified this hypothesis since no long-term changes in VEP amplitude were seen after scopolamine infusion prior to CCh. However, this correlation did not remain significant in multivariate analysis in accordance with Campeotto et al, as opposed to the study by Josefsson et al. Thirdly, the use of antibiotics impacted fcalprotectin levels. Indeed, throughout the study f-calprotectin correlated negatively with ante and per natal antibiotics in univariate and multivariate analyses. To our knowledge, the current study is first to demonstrate such impact. Indeed, earlier studies have shown changes in the gut microbiota establishment in infants born from mothers who had received antibiotic per partum. Likewise, a negative correlation was found with neonatal antibiotic courses in univariate analysis, but in contrast to other studies this correlation did not remain significant in multivariate analysis. However, in the latter study a correlation was only observed in infants treated with cefotaxim and meropenem, two broad-spectrum antibiotics. To summarize, factors known to delay gut bacterial colonization correlated negatively with fecal calprotectin levels, whereas factors known to favor gut bacterial colonization correlated positively with fecal calprotectin levels. This is in accordance with the study of Mohan et al, who described a decrease in f-calprotectin levels in infants supplemented with a probiotic strain. In the latter study, probiotic supplementation increased bifidobacteria levels, and decreased the levels of clostridia, a genus positively correlated in with fcalprotectin in the current study. By contrast, a recent study did not find any correlation between gut microbiota colonization and f-calprotectin: however, the culture techniques used in that report did not allow detection of clostridia. Otherwise, we observed a highly significant, positive correlation between the volume of VE-822 enteral feeding and fcalprotectin excretion in multivariate analysis, as previously reported. This effect was robust and stable. Interestingly, i.p. infusion of scopolamine prior to CCh led to the same results as cortical infusion confirming that scopolamine i.p. could act at a local cortical target. However, three findings suggest that mAChRs are involved in the induction of pathways generating long-term enhancement of electrophysiological responses, acting as a trigger mechanism rather than directly enhancing the ongoing neuronal excitability.