Neural tissue of the pituitary gland, also known as the neurohypophysis. It consists of the distal axons of neurons that produce VASOPRESSIN and oxytocin in the supraoptic nucleus and the PARAVENTRICULAR NUCLEUS. These axons travel down through the median eminence, the hypothalamic infundibulum of the PITUITARY STALK, to the posterior lobe of the pituitary gland.