HIERARCHICAL ORGANIZATION OF THE HUMAN BRAIN The brain can be divided into four interconnected areas: brainstem, diencephalon, limbic, and cortex. The structural and functional complexity increases from the lower, simpler areas of the brainstem up to the cortex. The cortex mediates the most uniquely “human” functions such as speech and language, abstract cognition, and the capacity to reflect on the past and envision the future.
