The positronic brain was an extremely sophisticated computation device capable of artificial sentience, created by Dr. Noonian Soong, based on an idea from author Isaac Asimov. It was this unit that enabled Soong's Soong-type androids to achieve true sentience.

This device consisted of an artificial neural network, designed to imitate the humanoid brain. The construction of a positronic brain was extremely complex, and Dr. Soong was the only scientist to have done so successfully, on at least six occasions: two unspecified prototypes, B-4, Lore, Data, and Juliana Soong (although B-4, Data, and Juliana Soong were the only truly stable units). Lore's positronic net differed from Data's: it had a Type L phase discriminator compared to Data's Type R.

One of the difficulties in creating a stable positronic brain was determining how the electron resistance across the neural filaments was to be resolved.

A submicron matrix transfer was a technique for replicating existing new neural pathways in a positronic brain into another positronic brain. This technology was introduced at a cybernetics conference that Data attended, in 2366. Using this technology, Data was able to replicate his neural pathways and created a new android, his daughter Lal. However, Lal's positronic net suffered a cascade failure, and ceased functioning.