Direct projections from the medulla oblongata to selective cortical areas in the rat.

Injections of horseradish peroxidase into different cortical areas reveal that neurons located in the rostroventral medulla oblongata innervate restricted cortical areas: the anterior and posterior cingulate cortex and the insular cortex. Other cortical areas do not receive medullary projections. Neurons projecting to both the anterior and the posterior cingulate cortex lie scattered throughout a wide territory of the ventrorostral medulla, whereas neurons projecting to the insular cortex are restricted to more medial regions.