Structural Characteristics and Spatial Organization of Parvalbumin-Containing Neurons in Somatosensory Zone SI of the Cerebral Cortex in Rats

Abstract

The aim of the present work was to perform layer-by-layer morphometric and immunohistochemical studies of parvalbumin-positive (PA+) neurons in the somatosensory zone (SI) of the cerebral cortex in white mongrel rats (n = 10). Studies of frontal and tangential sections of thickness 60 and 4 μm revealed significant variation in shape, body size, and process branching among PA+ neurons in all cortical layers. The greatest proportion of PA+ neurons (47.1%) was located in cortical layer IV in the barrel formation zone. Studies of tangential sections showed that the greatest proportion of PA+ neurons was located in barrel septa (43%). These cells in layer IV were distributed most densely in barrel walls, such that their outlines were clearly visible. The quantitative dominance of PA+ neurons in septa may be linked with the direction of the course of their dendrites in the internal part of the barrel and the formation of dendrodendritic gap junctions, which may in turn provide the morphological basis for individual local pacemaker rhythmogenesis and regulation of the functional state of cortical columns.