Distinct in vivo dynamics of excitatory synapses onto cortical pyramidal neurons and parvalbumin-positive interneurons

Joshua B. Melander, Aran Nayebi, Bart C. Jongbloets, Dale A. Fortin, Maozhen Qin, Surya Ganguli, Tianyi Mao, Haining Zhong

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Cortical function relies on the balanced activation of excitatory and inhibitory neurons. However, little is known about the organization and dynamics of shaft excitatory synapses onto cortical inhibitory interneurons. Here, we use the excitatory postsynaptic marker PSD-95, fluorescently labeled at endogenous levels, as a proxy for excitatory synapses onto layer 2/3 pyramidal neurons and parvalbumin-positive (PV+) interneurons in the barrel cortex of adult mice. Longitudinal in vivo imaging under baseline conditions reveals that, although synaptic weights in both neuronal types are log-normally distributed, synapses onto PV+ neurons are less heterogeneous and more stable. Markov model analyses suggest that the synaptic weight distribution is set intrinsically by ongoing cell-type-specific dynamics, and substantial changes are due to accumulated gradual changes. Synaptic weight dynamics are multiplicative, i.e., changes scale with weights, although PV+ synapses also exhibit an additive component. These results reveal that cell-type-specific processes govern cortical synaptic strengths and dynamics.

Original languageEnglish (US)
Article number109972
JournalCell Reports
Issue number6
StatePublished - Nov 9 2021


  • Markov model
  • PSD-95
  • additive and multiplicative synaptic dynamics
  • in vivo two-photon imaging
  • log normality
  • parvalbumin-positive inhibitory interneuron
  • shaft excitatory synapses
  • structural plasticity
  • synaptic weight

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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