Chronic 2P-STED imaging reveals high turnover of dendritic spines in the hippocampus in vivo

Elife. 2018 Jun 22;7:e34700. doi: 10.7554/eLife.34700.


Rewiring neural circuits by the formation and elimination of synapses is thought to be a key cellular mechanism of learning and memory in the mammalian brain. Dendritic spines are the postsynaptic structural component of excitatory synapses, and their experience-dependent plasticity has been extensively studied in mouse superficial cortex using two-photon microscopy in vivo. By contrast, very little is known about spine plasticity in the hippocampus, which is the archetypical memory center of the brain, mostly because it is difficult to visualize dendritic spines in this deeply embedded structure with sufficient spatial resolution. We developed chronic 2P-STED microscopy in mouse hippocampus, using a 'hippocampal window' based on resection of cortical tissue and a long working distance objective for optical access. We observed a two-fold higher spine density than previous studies and measured a spine turnover of ~40% within 4 days, which depended on spine size. We thus provide direct evidence for a high level of structural rewiring of synaptic circuits and new insights into the structure-dynamics relationship of hippocampal spines. Having established chronic super-resolution microscopy in the hippocampus in vivo, our study enables longitudinal and correlative analyses of nanoscale neuroanatomical structures with genetic, molecular and behavioral experiments.

Keywords: hippocampus; in vivo imaging; learning and memory; mouse; neuroscience; spine plasticity; super-resolution microscopy; synapses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Cerebral Cortex / surgery
  • Dendritic Spines / physiology
  • Dendritic Spines / ultrastructure*
  • Female
  • Gene Expression
  • Genes, Reporter
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Hippocampus / anatomy & histology
  • Hippocampus / physiology
  • Hippocampus / ultrastructure*
  • Image Processing, Computer-Assisted / statistics & numerical data
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Male
  • Memory / physiology
  • Mice
  • Mice, Transgenic
  • Microscopy, Fluorescence, Multiphoton / instrumentation
  • Microscopy, Fluorescence, Multiphoton / methods*
  • Molecular Imaging / instrumentation
  • Molecular Imaging / methods*
  • Nerve Net / anatomy & histology
  • Nerve Net / physiology
  • Nerve Net / ultrastructure*
  • Neuronal Plasticity / physiology
  • Pyramidal Cells / physiology
  • Pyramidal Cells / ultrastructure*
  • Synapses / physiology
  • Synapses / ultrastructure*


  • Bacterial Proteins
  • Luminescent Proteins
  • yellow fluorescent protein, Bacteria
  • Green Fluorescent Proteins

Grant support

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.