Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • News & Views
  • Published:

Learning and memory

Never fear, LTP is hear

Nature volume 390, pages 552–553 (1997)Cite this article

Synaptic transmission is the main mechanism by which neurons communicate, and an attractive hypothesis is that learning occurs, and memories are encoded, by activity-dependent changes in synaptic strength. With the discovery of hippocampal long-term potentiation (LTP), and the ability to study its mechanisms in experimentally accessible in vitro preparations, neurobiologists seemed to be on the verge of solving one of the more fascinating problems in neurobiology — the molecular basis for memory. But some reports have raised a nagging doubt as to whether LTP-like phenomena are actually used in the behaving animal during learning1. Now, complementary papers by Rogan et al.2 and McKernan and Shinnick-Gallagher3 (pages 604and of this issue) lay this doubt to rest. They show that fear conditioning, which is a form of pavlovian (classical) conditioning, indeed causes an increase in synaptic strength in the appropriate neural circuit.

Why has it been so difficult to make a connection between LTP and memory? Most studies have concentrated on the hippocampus, because this medial temporal lobe structure was the first one shown to be part of the brain's memory system4. Moreover, LTP was first described in the hippocampus5, and it is most easily studied in this structure. However, the exact functions of the hippocampus remain unclear and the hippocampal-dependent tasks that are often used in behavioural studies are complex. Thus, the exact information carried by the hippocampal synapses and circuits that are (presumably) modified during learning and memory is unknown. Combining sophisticated molecular genetic and electrophysiological techniques in the behaving animal has been a step in the right direction6. But the demonstration of an increase in hippocampal synaptic strength (that is, LTP) during learning has remained elusive.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Experiment by Rogan et al.2 to show the link between long-term potentiation and memory, using a fear-conditioning response.

References

  1. Eichenbaum, H. Nature 378, 131–132 (1995).

    Article  CAS  ADS  Google Scholar 

  2. Rogan, M. T., Stäubli, U. V. & LeDoux, J. E. Nature 390, 604–607 (1997).

    Article  CAS  ADS  Google Scholar 

  3. McKernan, M. G. & Shinnick-Gallagher, P. Nature 390, 607–611 (1997).

    Article  CAS  ADS  Google Scholar 

  4. Scoville, W. B. & Milner, B. J. Neurol. Neurosurg. Psychiat. 20, 11–21 (1957).

    Google Scholar 

  5. Bliss, T. V. P. & Lomo, T. J. Physiol. (Lond.) 232, 331–356 (1973).

    Google Scholar 

  6. Morris, R. G. M. & Morris, R. J. Nature 385, 680–681 (1997).

    PubMed  ADS  Google Scholar 

  7. Pavlov, I. P. Conditioned Reflexes (Dover, New York, 1927).

  8. LeDoux, J. E. Annu. Rev. Psychol. 46, 209–235 (1995).

    Google Scholar 

  9. Clugnet, M.-C. & LeDoux, J. E. J. Neurosci. 10, 2818–2824 (1990).

    Google Scholar 

  10. Rogan, M. T. & LeDoux, J. E. Neuron 15, 127–136 (1995).

    Google Scholar 

  11. Miserendino, M. J. D., Sananes, C. B., Melia, K. R. & Davis, M. Nature 345, 716–718 (1990).

    Article  CAS  ADS  Google Scholar 

  12. Gewirtz, J. C. & Davis, M. Nature 388, 471–474 (1997).

    Article  CAS  ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. the Departments of Psychiatry and Physiology, and the Departments of Cellular and Molecular Pharmacology, and Physiology, respectively, University of California, San Francisco, 94143, California, USA

    Robert C. Malenka & Roger A. Nicoll

Authors
  1. Robert C. Malenka
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Roger A. Nicoll
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Malenka, R., Nicoll, R. Never fear, LTP is hear. Nature 390, 552–553 (1997). https://doi.org/10.1038/37472

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/37472

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing