E - It allows the author to identify the problems that existed in the previous research.
Explanation:
As the excerpt states in the beginning: " Our thinking, perception, and ability to understand language are processed in the outermost layer of the brain. This area is known as the cerebral cortex. Researchers are still working to understand how the cerebral cortex is organized. Scientists have used a variety of techniques to map the brain's organization over the past century. However, these measures don't always reveal the same boundaries and borders in the brain's landscape." This tells up that there were problems before hand. Which goes with B.
