Premium
Barrelfield of the prenatally X‐irradiated rat somatosensory cortex: A histochemical and electrophysiological study
Author(s) -
Ito Muneyuki
Publication year - 1995
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903520208
Subject(s) - biology , electrophysiology , neuroscience , somatosensory system , cytochrome c oxidase , cortex (anatomy) , postsynaptic potential , excitatory postsynaptic potential , horseradish peroxidase , barrel cortex , stimulation , anatomy , extracellular , cerebral cortex , inhibitory postsynaptic potential , microbiology and biotechnology , biochemistry , mitochondrion , enzyme , receptor
The effect of prenatal X‐irradiation on the vibrissal cortical barrelfield of the brain of rats exposed to 200 R on the embryonic day 17 was studied morphologically and electrophysiologically. Cytoarchitectural barrels fail to appear in adult rats that have been subjected to this in utero treatment. However, sections cut in a plane tangential to the vibrissal cortex and examined for cytochrome oxidase (CO), a mitochondrial enzyme, contained a matrix of patterned CO activity which, albeit smaller and weaker in intensity, is similar to CO barrels in normal controls. Current source density analysis of cortical field potentials indicated that, as in the normal cortex, the earliest sink following peripheral stimulation appears in association with this high CO activity. These results suggest that the specific vibrissal thalamocortical pathway sets up an excitatory synaptic activity in the cortex of the irradiated animal. Efficacy of this route in eliciting postsynaptic spikes in the cortical output neurons was confirmed by recording extracellular spike responses to vibrissa displacements from layer Vb pyramidal neurons that were then injected intracellularly with horseradish peroxidase for later anatomical identification. © 1995 Wiley‐Liss, Inc.