Description
By using fluorescent retrograde tracers, we compared efferent projections of the medial frontal cortex to two subcortical areas: the superior colliculus, a somatic motor area, and the laterodorsal tegmental nucleus, a visceral motor area. Neurons projecting to the superior colliculus originated in layer V of the cingulate (Cg1 area) and medial agranular cortex, while neurons projecting to the laterodorsal tegmental nucleus originated in layers V and VI of the cingulate (Cg3 area) and infralimbic cortex. Thus, within the medial frontal cortex, the ventral portion (the Cg3 and infralimbic areas) may be a visceral motor area while the dorsal portion is a somatic motor region.