title: Complementary Patterns of Direct Amygdala and Hippocampal Projections to the Macaque Prefrontal Cortex.
abstract: The projections from the amygdala and hippocampus (including subiculum and presubiculum) to prefrontal cortex were compared using anterograde tracers injected into macaque monkeys (Macaca fascicularis, Macaca mulatta). Almost all prefrontal areas were found to receive some amygdala inputs. These connections, which predominantly arose from the intermediate and magnocellular basal nucleus, were particularly dense in parts of the medial and orbital prefrontal cortex. Contralateral inputs were not, however, observed. The hippocampal projections to prefrontal areas were far more restricted, being confined to the ipsilateral medial and orbital prefrontal cortex (within areas 11, 13, 14, 24a, 32, and 25). These hippocampal projections principally arose from the subiculum, with the fornix providing the sole route. Thus, while the lateral prefrontal cortex essentially receives only amygdala inputs, the orbital prefrontal cortex receives both amygdala and hippocampal inputs, though these typically target different areas. Only in medial prefrontal cortex do direct inputs from both structures terminate in common sites. But, even when convergence occurs within an area, the projections predominantly terminate in different lamina (hippocampal inputs to layer III and amygdala inputs to layers I, II, and VI). The resulting segregation of prefrontal inputs could enable the parallel processing of different information types in prefrontal cortex.
authors.affiliation: School of Psychology, Cardiff University, Cardiff, Wales CF10 3AT, UK.
authors.forename: John P
authors.initials: JP
authors.lastname: Aggleton
authors.affiliation: School of Psychology, Cardiff University, Cardiff, Wales CF10 3AT, UK.
authors.forename: Nicholas F
authors.initials: NF
authors.lastname: Wright
authors.affiliation: School of Medicine, Department of Anatomy and Neurobiology, Boston University, Boston MA 02118, USA.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Rosene
authors.affiliation: Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, MD 20892, USA.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Saunders
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000679:Amygdala / Q000502:physiology*; D000818:Animals; D001345:Autoradiography; D001931:Brain Mapping; D015331:Cohort Studies; D005260:Female; D007839:Functional Laterality; D006624:Hippocampus / Q000502:physiology*; D008252:Macaca fascicularis; D008253:Macaca mulatta; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology*
chemical_list: D000596:Amino Acids
keywords: anatomy; emotion; fornix; hippocampus; memory; subiculum