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Nature 420, 788-794 (19 December 2002) | doi:10.1038/nature01273; Received 18 July 2002; Accepted 23 October 2002

Long-term in vivo imaging of experience-dependent synaptic plasticity in adult cortex

Joshua T. Trachtenberg1,2, Brian E. Chen1,2, Graham W. Knott3, Guoping Feng4, Joshua R. Sanes4, Egbert Welker3 & Karel Svoboda1

  1. Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
  2. Institut de Biologie Cellulaire et de Morphologie, Université de Lausanne, Rue du Bugnon 9, CH 1005, Lausanne, Switzerland
  3. Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
  4. These authors contributed equally to this work

Correspondence to: Karel Svoboda1 Correspondence and requests for materials should be addressed to K.S. (e-mail: Email: svoboda@cshl.org).

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Do new synapses form in the adult cortex to support experience-dependent plasticity? To address this question, we repeatedly imaged individual pyramidal neurons in the mouse barrel cortex over periods of weeks. We found that, although dendritic structure is stable, some spines appear and disappear. Spine lifetimes vary greatly: stable spines, about 50% of the population, persist for at least a month, whereas the remainder are present for a few days or less. Serial-section electron microscopy of imaged dendritic segments revealed retrospectively that spine sprouting and retraction are associated with synapse formation and elimination. Experience-dependent plasticity of cortical receptive fields was accompanied by increased synapse turnover. Our measurements suggest that sensory experience drives the formation and elimination of synapses and that these changes might underlie adaptive remodelling of neural circuits.