The late maintenance of hippocampal LTP

Requirements, phases, 'synaptic tagging', 'late-associativity' and implications

Klaus G. Reymann, Julietta Uta Frey

Research output: Contribution to journalArticle

212 Citations (Scopus)

Abstract

Our review focuses on the mechanisms which enable the late maintenance of hippocampal long-term potentiation (LTP; >3 h), a phenomenon which is thought to underlie prolonged memory. About 20 years ago we showed for the first time that the maintenance of LTP - like memory storage - depends on intact protein synthesis and thus, consists of at least two temporal phases. Here we concentrate on mechanisms required for the induction of the transient early-LTP and of the protein synthesis-dependent late-LTP. Our group has shown that the induction of late-LTP requires the associative activation of heterosynaptic inputs, i.e. the synergistic activation of glutamatergic and modulatory, reinforcing inputs within specific, effective time windows. The induction of late-LTP is characterized by novel, late-associative properties such as 'synaptic tagging' and 'late-associative reinforcement'. Both phenomena require the associative setting of synaptic tags as well as the availability of plasticity-related proteins (PRPs) and they are restricted to functional dendritic compartments, in general. 'Synaptic tagging' guarantees input specificity and thus the specific processing of afferent signals for the establishment of late-LTP. 'Late-associative reinforcement' describes a process where early-LTP by the co-activation of modulatory inputs can be transformed into late-LTP in activated synapses where a tag is set. Recent evidence from behavioral experiments, which studied processes of emotional and cognitive reinforcement of LTP, point to the physiological relevance of the above mechanisms during cellular and system's memory formation.

Original languageEnglish (US)
Pages (from-to)24-40
Number of pages17
JournalNeuropharmacology
Volume52
Issue number1
DOIs
StatePublished - Jan 1 2007

Fingerprint

Maintenance
Proteins
Long-Term Potentiation
Synapses
Reinforcement (Psychology)

Keywords

  • LTP reinforcement
  • LTP-phases
  • Memory formation
  • Protein synthesis-dependent late-LTP
  • Synaptic tagging

ASJC Scopus subject areas

  • Pharmacology
  • Cellular and Molecular Neuroscience

Cite this

The late maintenance of hippocampal LTP : Requirements, phases, 'synaptic tagging', 'late-associativity' and implications. / Reymann, Klaus G.; Frey, Julietta Uta.

In: Neuropharmacology, Vol. 52, No. 1, 01.01.2007, p. 24-40.

Research output: Contribution to journalArticle

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