The structural organization of layer I of the adult human acoustic cortex. A Golgi and electron microscopy study.
The cellular morphology and the three dimensional cytoarchitecture of layer I of the adult human acoustic cortex were studied by using sagittal, transverse and tangential Golgi preparations and electron microscopy. The prominent neuron of layer I of the acoustic cortex is the Retzius-Cajal cell which is a solitary neuron accompanied by satellite astrocytes located mostly below the pial surface in the upper third of the layer. This neuron demonstrates a marked polymorphism in the various regions of the acoustic cortex. The anterior part of the Hessl convolutions contains Retzius-Cajal cells which are horizontal, multipolar forming dense dendritic arborization by extending long horizontal dendrites to all directions within a tangential plane parallel to the surface of the convolutions. The axon of the Retzius-Cajal cell is a long myelinated nerve fibre which mostly run horizontally, parallel to the pial surface, descending finally to the deeper parts of the layer and projecting a large number of axonic collaterals which radiate in all directions forming dense axonic networks. The Retzius-Cajal cell in the posterior part of the Hessl convolutions is a large polyhedral or triangular cell which extends a large number of dendrites, forming two dendritic networks: one in the upper third of the layer and another in middle part of it. Both of the networks communicate with the axonic collaterals of the Retzius-Cajal cells, forming numerous axodendritic synapses as can be clearly seen in electron microscopy.(ABSTRACT TRUNCATED AT 250 WORDS)
Baloyannis
S J
SJ
Department of Neurology, Aristotelian University, Thessaloniki, Greece.
Manolides
S
S
Arzoglou
L
L
Costa
V
V
Manolides
L
L
D000328:Adult; D001303:Auditory Cortex / Q000166:cytology* / Q000648:ultrastructure; D001369:Axons / Q000648:ultrastructure; D003712:Dendrites / Q000648:ultrastructure; D004721:Endoplasmic Reticulum / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000648:ultrastructure; D006801:Humans; D007382:Intermediate Filaments / Q000648:ultrastructure; D007395:Interneurons / Q000166:cytology*; D008854:Microscopy, Electron; D008928:Mitochondria / Q000648:ultrastructure; D009412:Nerve Fibers / Q000648:ultrastructure; D009434:Neural Pathways / Q000166:cytology; D009474:Neurons / Q000166:cytology*; D013194:Staining and Labeling; D013569:Synapses / Q000648:ultrastructure; D013570:Synaptic Membranes / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000648:ultrastructure