Preserved number of entorhinal cortex layer II neurons in aged macaque monkeys

A. H. Gazzaley, M. M. Thakker, P. R. Hof, John Morrison

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The perforant path, which consists of the projection from the layer II neurons of the entorhinal cortex to the outer molecular layer of the dentate gyrus, is a critical circuit involved in learning and memory formation. Accordingly, disturbances in this circuit may contribute to age-related cognitive deficits. In a previous study, we demonstrated a decrease in N-methyl-D-aspartate receptor subunit 1 immunofluorescence intensity in the outer molecular layer of aged macaque monkeys. In this study, we used the optical fractionator, a stereological method, to determine if a loss of layer II neurons occurred in the same animals in which the N-methyl-D-aspartate receptor subunit 1 alteration was observed. Our results revealed no significant differences in the number of layer II neurons between juvenile, young adult, and aged macaque monkeys. These results suggest that the circuit-specific decrease in N-methyl-D-aspartate receptor subunit 1 reported previously occurs in the absence of structural compromise of (he perforant path, and thus may be linked to an age-related change in the physiological properties of this circuit.

Original languageEnglish (US)
Pages (from-to)549-553
Number of pages5
JournalNeurobiology of Aging
Issue number5
StatePublished - Sep 1 1997
Externally publishedYes



  • Aging
  • Entorhinal cortex
  • Macaque monkey
  • Optical fractionator
  • Stereology

ASJC Scopus subject areas

  • Clinical Neurology
  • Biological Psychiatry
  • Developmental Neuroscience
  • Neurology
  • Psychology(all)

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