Fig. 7.

Topographic distribution of presynaptic active zones in the parasagittal slice. PSPs were evoked in PVN neurons with glutamate microstimulation in three positions in the parasagittal plane: caudal to the PVN, rostral to the PVN, and at the base of the hypothalamus dorsal to the optic chiasm, as shown by thelight and dark gray circles. Eachgray circle marks the spot at which glutamate microstimulation evoked a synaptic response in a PVN neuron. The sites at which the glutamate microdrops elicited synaptic responses identified as IPSPs are shown by the dark gray circles. The positions in which glutamate microdrops never elicited a synaptic response are designated with black circles. Rostral is to the right. AC, Anterior commissure;DA, dorsal hypothalamic area; DMD, dorsomedial hypothalamic nucleus; Fx, fornix;LA, lateral hypothalamus; MPA, medial preoptic area; MS, medial septum; OX, optic chiasm; PH, posterior hypothalamic area;Rch, retrochiasmatic area; VMH, ventromedial hypothalamic nucleus.