Figure 3.

The “extended-hippocampal system” proposed by Aggleton et al. (2010). Color-coded diagram depicts how, in the rat, the hippocampal formation is associated with three sets of parallel mammillary body—anterior thalamic connections. Connectivity studies in the monkey brain (macaque) support the same overall scheme for primates (e.g., Vann et al., 2007). The connections solely conveyed in the fornix are shown as dashed lines. Double-headed arrows depict reciprocal connections. Abbreviations: DtG, dorsal tegmental nucleus of Gudden; MTT, mammillothalamic tract; VtGp, ventral tegmental nucleus of Gudden, pars posterior. (Note, the lateral dorsal thalamic nucleus has not been included above as, unlike the anterior thalamic nuclei, it receives few, if any, mammillary body inputs. The interoanteromedial nucleus has not been included given its uncertain status in the primate brain).