silent synapse
A synaptic connection containing only NMDA receptors, functionally inactive at resting potential but recruitable during plasticity.
Full Definition
Silent synapses are immature or plastic synaptic connections that contain NMDA receptors but lack functional AMPA receptors. At resting membrane potentials, these synapses cannot transmit signals due to voltage-dependent NMDA receptor blocking by magnesium ions. However, they can be 'unsilenced' through activity-dependent mechanisms that insert AMPA receptors, converting them to functional synapses. This process is crucial for learning, memory formation, and developmental plasticity. Silent synapses are extensively studied in synaptic plasticity research and appear in literature on learning mechanisms.
Usage
Usage note: Distinguish from simply 'weak' or 'inactive' synapses, which may still have functional AMPA receptors.
In Context
- "Learning protocols converted silent synapses to functional connections in the hippocampus." — Plasticity research manuscript
- "The proportion of silent synapses decreased during critical period development." — Developmental neuroscience paper