Type I, II and III MnPO-PVN neurones were located throughout the rostral–caudal and dorsal–ventral extent of the MnPO. The location of non-responsive neurones was similar (sites not shown). Coordinates are in reference to bregma using standard sections from the atlas of Paxinos and Watson (Paxinos & Watson, 1998). dMnPO, dorsal median preoptic nucleus; vMnPO, ventral median preoptic nucleus; AC, anterior commissure; f, fornix; 3V, 3rd ventricle; OX, optic chiasm.