Synaptic plasticity and the analysis of the field-EPSP as well as the population spike using separate recording electrodes in the dentate gyrus in freely moving rats

Sabine Frey, Julietta U. Frey

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Commonly, synaptic plasticity events such as long-term potentiation (LTP) are investigated by using a stimulation electrode and a single, monopolar field recording electrode in the dentate gyrus in intact, freely moving rats. The recording electrode is mostly positioned in the granular cell layer, or the hilar region of the dentate gyrus, i.e. far away from the place of generation of monosynaptic postsynaptic excitatory potentials (EPSP). Since LTP is a synaptic phenomenon and field recordings far away from the activated synapses do not guarantee a specific interpretation of the overlaid, mixture of complex potentials of several different electrical fields it is often difficult or even impossible to interpret the data obtained by such a single recording electrode. Therefore, at least a separate or two recording electrodes should be used to record the EPSP as well as the spike, respectively, ideally at their places of generation. Here, we describe a method by implanting a chronic bipolar recording electrode which fulfils the above requirements by recording the field-EPSP as well as the population spike at their places of generation and describe the time course of LTP measured using this "double-recording" electrode. We show that different tetanization protocols resulted in EPSP- or population spike-LTP but only if the potentials were recorded by electrodes positioned within adequate places of potential generation. Interestingly, the commonly used recording in the hilus of a distinct part of a potential, mistakenly analyzed as an "EPSP" did not reveal any LTP.

Original languageEnglish (US)
Pages (from-to)79-87
Number of pages9
JournalJournal of Neuroscience Methods
Volume184
Issue number1
DOIs
StatePublished - Oct 30 2009

Keywords

  • Dentate gyrus
  • Electrophysiological recordings
  • Field-EPSP
  • Freely moving rat
  • Population spike

ASJC Scopus subject areas

  • Neuroscience(all)

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