Hebbian modification of a hippocampal population pattern in the rat

Authors

  • Charles King,

    1. Center for Molecular and Behavioural Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, USA
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  • Darrell A. Henze,

    1. Center for Molecular and Behavioural Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, USA
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  • Xavier Leinekugel,

    1. Center for Molecular and Behavioural Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, USA
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  • György Buzsáki

    Corresponding author
    1. Center for Molecular and Behavioural Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, USA
    • Corresponding author
      G. Buzsáki: Center for Molecular and Behavioural Neuroscience, Rutgers University, 197 University Avenue, Newark, NJ 07102, USA. Email: buzsaki@axon.rutgers.edu

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  • Author's present address

    X. Leinekugel: Inserm U 29, Maternité de Port-Royal, Paris 75014, France.

Abstract

  • 1The study of the physiological role of long-term potentiation (LTP) is often hampered by the challenge of finding a physiological event that can be used to assess synaptic strength. We explored the possibility of utilising a naturally occurring event, the hippocampal sharp wave (SPW), for the assessment of synaptic strength and the induction of LTP in vivo.
  • 2We used two methods in which hippocampal cells were either recorded intracellularly or extracellularly in vivo. In both cases, a linear association between the magnitude of the SPW and cellular responsiveness was observed.
  • 3LTP was induced by depolarising cells during SPWs by either direct intracellular current injection or extracellular microstimulation adjacent to the cell body. Both of these approaches led to an increase in the slope of the linear association between SPWs and cellular responsiveness.
  • 4This change was achieved without a rise in overall cell excitability, implying that the synapses providing input to CA1 cells during sharp waves had undergone potentiation.
  • 5Our findings show that the Hebbian pairing of cellular activation with spontaneous, naturally occurring synaptic events is capable of inducing LTP.

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