ABSTRACT
Structures or entities that are morphologically similar but that cannot, in principle, be traced back to a stipulated common precursor are homoplastic. The first school bases the concept of homology on structural correspondence and the second bases it on common ancestry. The coincidence of the events has prompted a review of current thinking on the concept of homology and re-examination of the classes of data available for the recognition of homology in the central nervous system. The central nervous system functions as a communications and regulatory agency because the various populations of neurons receive inputs of information from other neurons or sensory receptors impinging on their cell bodies and cell processes, integrate input information, and transmit data. In general, dendrite processes carry information toward the soma and axonal processes carry information away from the soma to other neurons or to effectors.
