Pull-Push Neuromodulation of LTP and LTD Enables Bidirectional Experience-Induced Synaptic Scaling in Visual Cortex

SummaryNeuromodulatory input, acting on G protein-coupled receptors, is essential for the induction of experience-dependent cortical plasticity. Here we report that G-coupled receptors in layer II/III of visual cortex control the polarity of synaptic plasticity through a pull-push regulation of LTP and LTD. In slices, receptors coupled to Gs promote LTP while suppressing LTD; conversely, receptors coupled to Gq11 promote LTD and suppress LTP. In vivo, the selective stimulation of Gs- or Gq11-coupled receptors brings the cortex into LTP-only or LTD-only states, which allows the potentiation or depression of targeted synapses with visual stimulation. The pull-push regulation of LTP/LTD occurs via direct control of the synaptic plasticity machinery and it is independent of changes in NMDAR activation or neuronal excitability. We propose these simple rules governing the pull-push control of LTP/LTD form a general metaplasticity mechanism that may contribute to neuromodulation of plasticity in other cortical circuits.

► Neuromodulators exert a pull-push control of LTP and LTD ► Gq10-coupled receptors promote LTD and suppress LTP ► Gs-coupled receptors promote LTP and suppress LTD ► Gs- and Gq11-coupled receptors can gate experience-dependent synaptic scaling