title: Cyto- and chemoarchitecture of the cortex of the tammar wallaby (Macropus eugenii): areal organization.
abstract: We have examined the cyto- and chemoarchitecture of the isocortex of a diprotodontid marsupial, the tammar wallaby (Macropus eugenii), using Nissl staining in combination with enzyme histochemical (acetylcholinesterase - AChE, NADPH-diaphorase - NADPHd, cytochrome oxidase) and immunohistochemical (non-phosphorylated neurofilament - SMI-32) markers. The primary sensory cortex showed distinctive patterns of reactivity in cytochrome oxidase, acetylcholinesterase and NADPH diaphorase. For example, in AChE material, S1 showed a heterogeneous appearance, with regions exhibiting a double layer of AChE activity (layers II and IV) adjacent to poorly reactive regions. In NADPHd preparations, activity in S1 was strongest in layers I to IV although, as in AChE material, there were consistent patches of reduced NADPHd activity which corresponded to poorly reactive regions in the AChE sections. Each of the primary sensory areas of the isocortex showed a different pattern of distribution of SMI-32+ neurons. In V1, SMI-32+ neurons were distributed in two layers (III and V) throughout the tangential extent of that region. In S1, SMI-32+ neurons were concentrated in layer V, but large and discrete patches within S1 had additional SMI-32+ neurons in layer III. In primary auditory cortex there was a dense band of SMI-32+ neurons in layer V, with only occasional labeled pyramidal neurons in layer III. In the secondary sensory areas (V2 and S2) SMI-32+ neurons were either distributed in layers III and V (V2) or solely within layer V (S2). The tangential and laminar distribution of Type I reactive NADPH diaphorase neurons in the tammar wallaby cortex was more like that seen in eutheria than in polyprotodontid metatheria.
authors.affiliation: Department of Anatomy, School of Medical Sciences, The University of NSW, Sydney, Australia. k.ashwell@unsw.edu.au
authors.forename: K W S
authors.initials: KW
authors.lastname: Ashwell
authors.forename: L-L
authors.initials: LL
authors.lastname: Zhang
authors.forename: L R
authors.initials: LR
authors.lastname: Marotte
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D001931:Brain Mapping; D003576:Electron Transport Complex IV / Q000378:metabolism; D007614:Macropodidae / Q000033:anatomy & histology* / Q000378:metabolism; D009252:NADPH Dehydrogenase / Q000378:metabolism; D019579:Neocortex / Q000166:cytology* / Q000201:enzymology*; D016900:Neurofilament Proteins / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000201:enzymology; D014018:Tissue Distribution
chemical_list: D016900:Neurofilament Proteins; D009252:NADPH Dehydrogenase; D003576:Electron Transport Complex IV; D000110:Acetylcholinesterase