crosssynaptic

Crosssynaptic is a term used in neuroscience to describe cross-synaptic signaling, the interaction between synapses that influences their activity and plasticity. It refers to phenomena where activity at one synapse can affect neighboring synapses on the same neuron (or on nearby neurons) through multiple pathways, rather than isolated, strictly confined synaptic transmission.

Spillover transmission occurs when neurotransmitter released at one synapse diffuses to activate extrasynaptic receptors at adjacent synapses, altering their efficacy. Ephaptic coupling refers to electrical fields generated by active neurons that can modulate the membrane potential of nearby neurons or synapses. Glial networks, particularly astrocytes, can sense neurotransmitter release and release gliotransmitters (such as glutamate, ATP) that modulate multiple nearby synapses, creating cross-synaptic effects. Structural features like perisynaptic astrocyte processes and extracellular matrix can shape these interactions. In some cases synapses may share released neuromodulators that diffuse over longer distances, linking synaptic changes across a local circuit.

Crosssynaptic signaling may influence synaptic integration, timing, and plasticity, contributing to synchronized activity and network-level computations. It is considered a potential factor in clustering of plastic changes during learning and in shaping receptive fields. The concept remains a subject of ongoing investigation, and researchers emphasize that crosssynaptic effects can be context-dependent and vary by brain region.

Researchers use electrophysiology, imaging of calcium and neurotransmitter dynamics, optogenetics, and computational modeling to study crosssynaptic interactions, often aiming to distinguish true cross-synaptic effects from conventional, monosynaptic transmission.

See also: synaptic spillover, ephaptic coupling, gliotransmission, synaptic plasticity.