Fig. 1.
Schematic diagram showing a lateral view of the rat cerebral cortex (top) and a representative cross section (bottom) taken at the level of approximately the anteroposterior midpoint of the septal nucleus. In the coronal section, the locations of area Cg1 and Par 1 of Zilles (1990) and of areas AgM and AgL (Donoghue and Wise, 1982) are shown. Qualitative analyses were performed at representative rostrocaudal levels within each of these four areas. Quantitative measures were derived from sections matching the cross section depicted. In each section used for quantitative study, camera lucida drawings of tyrosine hydroxylase-immunoreactive fibers were obtained from layer II/III and from layer V of all four areas. In total, these drawings subtended virtually the entire span of areas Cg1, AgM, and AgL present within the section; the stippled area offset with dashed lines within area Par1 illustrates the approximate location of the subportion of this region from which quantitative measures were obtained. olf, Olfactory bulb; cc, corpus callosum; cd, caudate nucleus.