title: Three-dimensional organization of dendrites and local axon collaterals of shell and core medium-sized spiny projection neurons of the rat nucleus accumbens.
abstract: Medium-sized spiny projection neurons (MSN) in the head of the primate caudate nucleus are thought to have preferred dendritic orientations that tend to parallel the orientations of the striosomes. Moreover, recurrent axon collaterals of MSN in the rat dorsal striatum have been categorized into two types, i.e., restricted and widespread. The nucleus accumbens (Acb) has a highly complex compartmental organization, and the spatial organization of dendritic and axonal arbors of MSN has not yet been systematically studied. In this study, using single-cell juxtacellular labeling with neurobiotin as well as anterograde neuroanatomical tracing with biotinylated dextran amine, we investigated the three-dimensional (3D) organization of dendrites and axons of MSN of the rat Acb in relation to subregional (shell-core) and compartmental (patch-matrix) boundaries. Our results show that dendritic arbors of MSN in both the Acb shell and core subregions are preferentially oriented, i.e., they are flattened in at least one of the 3D-planes. The preferred orientations are influenced by shell-core and patch-matrix boundaries, suggesting parallel and independent processing of information. Dendritic orientations of MSN of the Acb core are more heterogeneous than those of the shell and the dorsal striatum, suggesting a more complex distribution of striatal inputs within the core. Although dendrites respect the shell-core and patch-matrix boundaries, recurrent axon collaterals may cross these boundaries. Finally, different degrees of overlap between dendritic and axonal arborizations of individual MSN were identified, suggesting various possibilities of lateral inhibitory interactions within and between, functionally distinct territories of the Acb.
authors.affiliation: Department of Anatomy and Neurosciences, Amsterdam, Research Institute Neurosciences Vrije Universiteit, VU University Medical Center, P.O. Box 7057, MF-G102, 1007 MC, Amsterdam, The Netherlands.
authors.forename: Yvette C
authors.initials: YC
authors.lastname: van Dongen
authors.forename: Philippe
authors.initials: P
authors.lastname: Mailly
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Thierry
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Groenewegen
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Deniau
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D001710:Biotin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000378:metabolism; D003712:Dendrites / Q000502:physiology*; D049229:Dendritic Spines / Q000502:physiology; D003911:Dextrans / Q000008:administration & dosage / Q000378:metabolism; D004594:Electrophysiology; D006624:Hippocampus / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007150:Immunohistochemistry; D008297:Male; D008845:Microinjections; D009415:Nerve Net / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism; D009434:Neural Pathways / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000033:anatomy & histology / Q000166:cytology* / Q000378:metabolism; D017397:Prefrontal Cortex / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003911:Dextrans; C076397:biotinylated dextran amine; C070614:neurobiotin; D001710:Biotin