Dynamic Recovery from Depression Enables Rate Encoding in Inhibitory Synapses

Morgan S. Bridi, Sangyep Shin, Shiyong Huang, Alfredo Kirkwood

Research output: Contribution to journalArticlepeer-review


Parvalbumin-expressing fast-spiking interneurons (PV-INs) control network firing and the gain of cortical response to sensory stimulation. Crucial for these functions, PV-INs can sustain high-frequency firing with no accommodation. However, PV-INs also exhibit short-term depression (STD) during sustained activation, largely due to the depletion of synaptic resources (vesicles). In most synapses the rate of replenishment of depleted vesicles is constant, determining an inverse relationship between depression levels and the activation rate, which theoretically, severely limits rate-coding capabilities. We examined STD of the PV-IN to pyramidal cell synapse in the mouse visual cortex and found that in these synapses the recovery from depression is not constant but increases linearly with the frequency of use. By combining modeling, dynamic clamp, and optogenetics, we demonstrated that this recovery enables PV-INs to reduce pyramidal cell firing in a linear manner, which theoretically is crucial for controlling the gain of cortical visual responses.

Original languageEnglish (US)
Article number100940
Issue number3
StatePublished - Mar 27 2020


  • Biological Sciences
  • Cellular Neuroscience
  • Mathematical Biosciences
  • Molecular Neuroscience
  • Neuroscience

ASJC Scopus subject areas

  • General


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