Induction and transient suppression of long-term potentiation in the peri- and postrhinal cortices following theta-related stimulation of hippocampal field CA1

Graham Cousens, Timothy A. Otto

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

During behavioral events associated with periods of likely mnemonic processing, CA1 pyramidal cells in rats typically discharge repetitively in either high-frequency bursts ('complex spikes') or single spikes, both of which are tightly phase-locked to the hippocampal them rhythm. Interestingly, patterned stimulation which mimics the repetitive, learning-related complex spike discharges are optimal for inducing long-term potentiation (LTP) of excitatory field potentials in CA1, and patterned stimulation which mimics the theta-related single action potentials results in a robust and lasting depotentiation at these same synapses. The aim of the present study was to determine the extent to which these physiologically-relevant patterns of hippocampal stimulation have similar effects on synaptic efficacy in the monosynaptic projection from CA1 to the perirhinal and postrhinal cortices (PRh), areas thought to play a prominent role in many forms of learning and memory. Single-pulse stimulation of CA1 evoked a small amplitude, short latency population excitatory postsynaptic potential (EPSP) in the PRh. Theta-burst stimulation (TBS; n = 8) delivered to CA1 reliably potentiated the PRh EPSP slope for at least 30 min. Theta-pulse stimulation (TPS; 5 Hz; n = 4) delivered to CA1 5 min after TBS substantially but transiently suppressed EPSP slope relative to that of potentiated control preparations. Collectively these data suggest that theta-related patterns of hippocampal activation can reliably induce and transiently suppress LTP in PRh, and are consistent with the notion that behaviorally-relevant, theta-modulated patterns of CA1 unit activity may result in both long- and short-term alterations of synaptic strength within their rhinal cortical targets.

Original languageEnglish (US)
Pages (from-to)95-101
Number of pages7
JournalBrain research
Volume780
Issue number1
DOIs
StatePublished - Jan 5 1998

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

Keywords

  • Depotentiation
  • Hippocampus
  • Long-term potentiation (LTP)
  • Perirhinal
  • Rhinal cortex

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