A central tenet of most theories of synaptic modification during cortical development is that correlated activity drives plasticity in synaptically connected neurons. Unexpectedly, however, using sensory-evoked activity patterns recorded from the developing mouse cortex in vivo, the synaptic learning rule that we uncover here relies solely on the presynaptic neuron. A burst of three presynaptic spikes followed, within a restricted time window, by a single presynaptic spike induces robust long-term depression (LTD) at developing layer 4 to layer 2/3 synapses. This presynaptic spike pattern-dependent LTD (p-LTD) can be induced by individual presynaptic layer 4 cells, requires presynaptic NMDA receptors and calcineurin, and is expressed presynaptically. However, in contrast to spike timing-dependent LTD, p-LTD is independent of postsynaptic and astroglial signaling. This spike pattern-dependent learning rule complements timing-based rules and is likely to play a role in the pruning of synaptic input during cortical development.
► Natural spike patterns in layer 4 neurons induce LTD at downstream synapses ► Spike pattern-dependent LTD can be induced in individual presynaptic neurons ► Spike pattern-dependent LTD requires presynaptic NMDA receptors and calcineurin ► Spike pattern-dependent LTD is independent of postsynaptic and astroglial signaling
Using natural spike patterns recorded from cortical layer 4 neurons in vivo, Rodríguez-Moreno et al. uncover a new spike pattern-dependent synaptic learning rule. They find that individual presynaptic neurons can drive NMDA receptor-dependent synaptic depression without a requirement for postsynaptic activity.