The period saw a consolidation of the idea that synaptic strength and connectivity can be modified by activity, integrating chemical transmission, receptor action, and synaptic architecture as core mechanisms of plasticity. Studies highlighted distinct synapse types, including axo-somatic and axo-dendritic contacts, and revealed non-spike, graded transmitter release as a route to plastic change, expanding the traditional view of transmission. The formation and maturation of synaptic junctions in developing brain provided a structural blueprint for experience-dependent refinement of networks. Historical Significance: By showing that synapses are not static, the era established activity-dependent plasticity as a fundamental principle guiding development, learning, and circuit adaptation, setting the stage for later molecular dissection of plasticity mechanisms and circuit-level learning rules, and prompting exploration of specialized synapses as substrates for modification in complex networks.