Non-dopaminergic projection from the subparafascicular area to the temporal cortex in the rat

Following injection of fluorescent tracer into the rat temporal cortex, retrogradely labeled cells were found in the subparafascicular area. In the thalamus, numerous cell labeling was seen in the medial geniculate complex. Labeled cells in the subparafascicular area were small (10-20 microns), and did not display tyrosine hydroxylase immunoreactivity. From these findings, the subparafascicular area has, at least, two distinct projection systems towards the cerebral cortex; the previously described large dopaminergic cells innervating the frontal cortex and small non-dopaminergic cells innervating the temporal cortex.