Higher brain functions such as perception and memory are first-person internal sensations whose mechanisms can have options to concurrently activate motor neurons for behavioral action. By setting up all the required constraints using available information from different levels, a theoretical examination from a first-person frame of reference led to the derivation of a first-principle of the structure-function units. These units operate in synchrony with the synaptically-connected neural circuitry. These units are capable of explaining and interconnecting findings from various levels and enable triangulation of a large number of observations from both the normal and loss of function states of the system. Indirect evidence for the presence of a comparable circuitry in a remote species − Drosophila − suggests the universal presence of these units across the animal kingdom. The key features of the basic unit meet the expectations of the K-lines proposed for the development of artificial intelligence.