Introduced into neurophysiology by Charles S. Sherrington (1857-1952), it forms part of the principle of convergence of connections. Take, for example, the case of one neuron that has many synaptic connections with other nerve cells. The sum of the excitatory and inhibitory synaptic effects at any one moment determines the activity of the neuron. This neuron is then said to represent the final common pathway for the neurons connecting with it, as it integrates the information from various sources into a unified response. Examples of a final common pathway are peripheral motoneurons that send axons and signals from the central nervous system to skeletal muscle fibers. In developmental psychology, it has been borrowed as a metaphor to carry the idea that certain functions (e.g., motor ones) may serve as a sort of conduit for the development of other functions (e.g., those labeled ‘cognitive’ or ‘social’).
See Axon, Motoneuron, Motor development, Motor unit, Neuron doctrine, Striated (or striped or voluntary) muscles, Synapse