The Interpeduncular nucleus is primarily GABAergic and contains at least two neuron clusters of different morphologies.[1] The region is divided into 7 paired and unpaired subnuclei
Subdivisions
The presence of non-homologous subdivisions of the Interpeduncular nucleus was first noticed by Cajal over a hundred years ago.[2] The currently recognized standard subdivision notation was mostly established by Hammill and Lenn in 1984 by combining the work and notations of four groups.[3] Although most of their proposed convention stuck, at some point the proposed "rostral lateral" sub-nucleus was renamed "dorsomedial" and became immortalized in brain atlases.
Apical sub-nucleus (IPA)
Unpaired sub-nucleus. Former names include: "caudal dorsal", "dorsal", and "pars dorsalis magnocellularis".[3]
Central sub-nucleus (IPC)
Unpaired sub-nucleus. Former names include: "rostral ventral", "caudal central", "posterior inter", and "pars medianus".[3]
Dorsolateral sub-nucleus (IPDL)
Paired sub-nucleus.
Dorsomedial sub-nucleus (IPDM)
Paired sub-nucleus. Former names include: "rostral lateral" and "interstitial".[3]
Intermediate sub-nucleus (IPI)
Paired sub-nucleus. Former names include: "caudal intermediate", "posterior inner" and "pars medianus".[3]
Lateral sub-nucleus (IPL)
Paired sub-nucleus. Former names include: "caudal lateral", "paramedian" and "pars lateralis".[3]
Rostral sub-nucleus (IPR)
Unpaired sub-nucleus. Former names include: "central" and "pars dorsalis".[3]
The Interpeduncular nucleus is thought to have a broad inhibitory effects on many other brain regions. IPN activity is linked with decreased dopamine release and utilization from dopamine producing regions.[5] The Interpeduncular nucleus is implicated with a role in the regulation of Rapid eye movement sleep.[6] Activation of the GAD2 expressing sub-population of the IPN produced the physical symptoms of nicotine withdrawal suggesting that the misfunction of this region may be an active component of withdrawal.[7]
^Gioia, Magda (1994), "A cluster analysis of the neurons of the rat interpeduncular nucleus", Journal of Anatomy, 185 ( Pt 3), University of Milan, Italy: Wiley-Blackwell: 459–464, PMC1166650, PMID7649781
^Ramón y Cajal, Santiago (1909). Histologie du Système Nerveux de l'Homme et des Vertébrés, L. Azoulay, trans. Paris: Maloine. Translated into English as Histology of the Nervous System of Man and Vertebrates (1995). New York: Oxford University Press.
^ abcdefgLenn, NJ; Hamill, GS (July 1984). "Subdivisions of the interpeduncular nucleus: a proposed nomenclature". Brain Research Bulletin. 13 (1): 203–4. doi:10.1016/0361-9230(84)90023-6. PMID6478267.
^Nishikawa, T; Fage, D; Scatton, B (May 14, 1986). "Evidence for, and nature of, the tonic inhibitory influence of habenulointerpeduncular pathways upon cerebral dopaminergic transmission in the rat". Brain Research. 373 (1–2): 324–36. doi:10.1016/0006-8993(86)90347-1. PMID2424555.
^Funato, Hiromasa (2010), Loss of Goosecoid-like and DiGeorge syndrome critical region 14 in interpeduncular nucleus results in altered regulation of rapid eye movement sleep, University of Texas Southwestern Medical Center, Dallas: PNAS