AIF1 and colitis: Finally, in the hypothalamus, DSS-induced colitis significantly reduced Iba-1 levels in the paraventricular nucleus of the hypothalamus (PVH) (F (1, 24) = 7.9; p = 0.01), the prime element of the hypothalamo-pituitary-adrenal axis and the stress output system (Fig. 2g), but did not influence Iba-1 levels in another hypothalamic region, the lateral hypothalamus (Fig. 2h).