synaptically

Synaptically is an adverb used in neuroscience to describe processes that pertain to synapses, the specialized junctions through which neurons communicate. It denotes that the mechanism or effect occurs at or through synaptic transmission, as opposed to being intrinsic to a neuron’s axon or dendrite alone.

Most synapses are chemical, involving release of neurotransmitters into a synaptic cleft and binding to postsynaptic receptors, though electrical synapses transmit signals via gap junctions. When a description refers to something happening synaptically, it emphasizes the dependence on the synapse for the observed effect, such as synaptically mediated excitation or inhibition, synaptically induced plasticity, or synaptically controlled firing patterns. Non-synaptic modes of signaling, by contrast, include volume transmission of neuromodulators or ephaptic coupling.

Common scientific contexts include synaptically driven changes in membrane potential, synaptically mediated long-term potentiation and depression, and the formation and remodeling of synaptic connections during development and learning. The term is used in both basic neuroscience and clinical literature to distinguish synapse-specific mechanisms from cell-intrinsic processes.

Etymology and usage: derived from synapse + -ically, the form is most often encountered in formal scientific writing. It is less common in everyday language and is typically used to specify the involvement of synaptic transmission in a task or phenomenon.