Abstract
This work describes the distribution of the central benzodiazepine-binding sites (BZD-BS) in several structures recently described as involved in memory processes. The study was performed on 4 postmortem human brains by in vitro quantitative autoradiography using 3H-flunitrazepam as a ligand. Very high densities of BZD-BS (1,500–2,000 fmol/mg protein) were observed in the anterior and posterior cingulate cortex, in the indusium griseum and in the accessory basal nucleus of the amygdala, and moderate concentrations (500–700 fmol/mg) in the magnocellular region of the mediodorsal thalamic nucleus. In the classical cerebral memory circuits, high densities of BZD-BS (1,000 to 1,500) were also found, except in the septum where the density of BZD-BS (400 to 600) was not significantly different from that in control structures not involved in memory. No evidence for lateralization of the sites was observed.