Attenuated activity across multiple cell types and reduced monosynaptic connectivity in the aged perirhinal cortex

Andrew P. Maurer, Sara N. Burke, Kamran Diba, Carol A. Barnes

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


The perirhinal cortex (PER), which is critical for associative memory and stimulus discrimination, has been described as a wall of inhibition between the neocortex and hippocampus. With advanced age, rats show deficits on PER-dependent behavioral tasks and fewer PER principal neurons are activated by stimuli, but the role of PER interneurons in these altered circuit properties in old age has not been characterized. In the present study, PER neurons were recorded while rats traversed a circular track bidirectionally in which the track was either empty or contained eight novel objects evenly spaced around the track. Putative interneurons were discriminated from principal cells based on the autocorrelogram, waveform parameters, and firing rate. While object modulation of interneuron firing was observed in both young and aged rats, PER interneurons recorded from old animals had lower firing rates compared with those from young animals. This difference could not be accounted for by differences in running speed, as the firing rates of PER interneurons did not show significant velocity modulation. Finally, in the aged rats, relative to young rats, there was a significant reduction in detected excitatory and inhibitory monosynaptic connections. Together these data suggest that with advanced age there may be reduced afferent drive from excitatory cells onto interneurons that may compromise the wall of inhibition between the hippocampus and cortex. This circuit dysfunction could erode the function of temporal lobe networks and ultimately contribute to cognitive aging.

Original languageEnglish (US)
Pages (from-to)8965-8974
Number of pages10
JournalJournal of Neuroscience
Issue number37
StatePublished - 2017


  • Hippocampus
  • Medial temporal lobe
  • Object field
  • Place field
  • Rat

ASJC Scopus subject areas

  • Neuroscience(all)


Dive into the research topics of 'Attenuated activity across multiple cell types and reduced monosynaptic connectivity in the aged perirhinal cortex'. Together they form a unique fingerprint.

Cite this