The extension of cell theory to nervous system by Santiago Ramon y Cajal (1832-1934) following Heinrich Waldeyer. It has two main theses, which form the basis of modern neuroscience: 1. the nervous system is composed of discrete units or cells, called neurons, that are both structurally and functionally discrete in having their own membranes and functioning as a fundamental signalling units, 2. the connections between these units is highly specific. The doctrine was first proposed by Waldeyer in the 1890s and then developed into its present articulation by Cajal using the cell staining technique discovered by Camillo Golgi (1843-1926), and combining the neuron concept with the synapse concept put forward by Charles S. Sherrington (1857-1952). At the time, the doctrine stood in stark contrast to existing theories that depicted the nervous system as an amorphous collection of cell bodies that essentially shared a common cell membrane and thus no specificity of connections.
See Cell theory, Final common pathway, Neuron, Neuroscience, Synapse