title: Development of cat somatosensory cortex: structural and metabolic considerations.
abstract: Although research is beginning to clarify the relationship between structure and functional activity in the adult cerebral cortex, little is known about cortical development in the somatosensory cortex of cats. A number of parameters were used in this study to identify functional and anatomical correlates in the developing somatosensory cortex of kittens ranging in age from 3 to 33 d: 2-deoxyglucose (2DG) uptake, cytochrome oxidase (CO) activity, Nissl staining, and AChE activity. All of these parameters were found to reflect an immaturity that evolved to the adult-like pattern by 4-5 weeks of age. Nissl staining revealed an immature laminar pattern at birth, in which layers I, V, and VI were distinct whereas layers II-IV were homogeneous in appearance. Numerous cells could be observed at the layer VI-white matter junction and throughout the white matter, a feature not found in adults. The laminar distribution of Nissl-stained cells gradually became mature by 4-5 weeks of age. CO staining was homogeneous throughout all layers, in contrast to the adult pattern, which displays laminar differentiation. In young animals, many darkly stained CO+ cells were found at the layer VI-white matter border and in the white matter, a distribution not found in the adult. AChE staining in kittens was also distinctly different from that in adults. At birth, AChE+ fibers could be found in layers I, V, and VI but were scarce in layers II-IV. In the adult, a dense network of AChE+ fibers can be found in all layers. 2DG uptake was also immature, as little stimulus-evoked activity could be observed in animals younger than 2 weeks. A dense band of metabolic activity was found in the zone between layer VI and the white matter, whether or not a somatic stimulus was delivered. These results suggest a close correlation between the developing cytoarchitecture and the emergence of a mature pattern of functional activity in the somatosensory cortex.
authors.affiliation: Department of Anatomy and Cell Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814.
authors.forename: R A
authors.initials: RA
authors.lastname: Code
authors.forename: S L
authors.initials: SL
authors.lastname: Juliano
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D002415:Cats / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism; D003847:Deoxyglucose / Q000493:pharmacokinetics; D003576:Electron Transport Complex IV / Q000378:metabolism; D005260:Female; D008297:Male; D009474:Neurons / Q000378:metabolism; D013003:Somatosensory Cortex / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism
chemical_list: D003847:Deoxyglucose; D003576:Electron Transport Complex IV; D000110:Acetylcholinesterase