Quantitative light-microscopic study of the nucleus medialis dorsalis of the thalamus in the intact cat, and after prefrontal cortical ablations.
The volume of the prefrontal cortex and of the thalamic nucleus medialis dorsalis, and the number of neurons in this nucleus were obtained, for adult cats of both sexes, using paraffin embedding and standard quantitative histological procedures. Changes in the nucleus medialis dorsalis after prefrontal cortical ablations were also quantified. All data were corrected for shrinkage. In the intact cat, the average volume of the prefrontal cortex was 235 mm3, the average volume of the nucleus medialis dorsalis was 24.5 mm3, and the number of neurons in this nucleus was 232,000. After cortical ablations which eliminated between 64% and 93% of the prefrontal cortex, the number of surviving neurons in the nucleus medialis dorsalis remained at 70%-55% of controls. When additional cortex (which surrounds the prefrontal cortex and is connectionally related to it) was damaged, the decrease in volume and neuron counts in the nucleus medialis dorsalis was proportional to the amount of cortex ablated. Even after large cortical ablations of this kind, over 45% of the neurons in the nucleus medialis dorsalis still survived. Some of the surviving neurons appeared in the core of maximal gliosis in the nucleus. No unquestionable side or sex differences were found.
Gonzalez
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Department of Morphology, School of Medicine, Autónoma University, Madrid, Spain.
Avendano
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D000818:Animals; D002415:Cats; D002452:Cell Count; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology; D005260:Female; D006652:Histological Techniques; D008297:Male; D009474:Neurons; D010477:Perfusion; D012737:Sex Factors; D013787:Thalamic Nuclei / Q000033:anatomy & histology* / Q000473:pathology