The "brain as a computer metaphor"-based technical reconstructions versus efforts to comprehend how the brain links the informational structure with its phenomenal constructs, such as perception, cognition, consciousness, agency, and free will—have all become increasingly important some years after the start of these programs. On the one hand, an engineering demonstration is in opposition to a more solidly founded scientific and philosophica undertaking. In all vertebrate animals, as well as the majority of invertebrate ones, the brain functions as the hub of the nervous system. It is situated inside the head, typically close to the sensory structures that support senses like vision. It is the most intricate organ in the body of a vertebrate. The cerebral cortex of an adult human has 14–16 billion neurons.
