Shown here are what’s known as “association” pathways--nerve fibers that connect two parts of the cortex--in the human brain. The large number of intracortical connections present in the human brain seems to be unique to our species. To generate this image, scientists dissected the temporal lobe, which is crucial for speech, from a cadaver and scanned it for 12 hours. One well-studied association pathway within this region is the arcuate fasciculus, which is crucial for language. It connects areas that process sound information with the area involved in our ability to produce vocalization.