IL6 and delirium: In order to investigate whether the detrimental effect of treatment with serum from delirium patients on neurogenesis and apoptosis during differentiation was also mediated by a higher concentration of IL6 in the serum samples of the same patients, we exposed cells to treatment with serum and an antibody against IL6, first during proliferation, then during differentiation, and finally during both proliferation and differentiation (Fig. 1d, e).