【英语时差8,16】前额皮质（上）（在线收听）

The prefrontal cortex is the region of the brain located just behind the forehead. This is where higher-level cognition occurs, such as recalling whether a word was heard aloud or read. Most people show evidence of more processing on one side of the cortex，the right side. However, research has shown that many elderly people use both hemispheres more equally, thus processing bilaterally. This discovery led to two opposing theories as to why. One theory supposes that this change in the prefrontal cortex is part of the general decline of the body, that bilateral processing is evidence of malfunctioning. The other theory supposes that enlisting the help of the other hemisphere of the prefrontal cortex is a way to compensate for reduced capacity in the more active hemisphere; that is, the brain is making up for its own failings.