The Prefrontal Cortex with Age
The Aging Prefrontal Cortex
The prefrontal cortex is the region of the brain located just behind the forehead, 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.
Scientists conducted a range of cognitive tests with older adults in their 60’s and 70’s. Then chose two smaller groups from those subjects–those who performed high on the tests, and those who performed low. The scientists then administered two of the same tests to the two groups of older adults, as well as to a group of young adults between the ages of 20 and 35 while the subjects’ brains were PET scanned. What they found was that the high-performing older adults showed significantly more use of bilateral processing than did anyone else.
The research supports the theory that bilateral processing is a way to compensate for reduced capacity of the right hemisphere with age. Further research may examine how training individuals or using drugs to enhance bilateral processing affects diseases such as Alzheimer’s.
The prefrontal cortex is located just behind the forehead, functioning in higher cognition, such as recalling whether a word has been heard or read. Most individuals have a more developed right hemisphere. Research shows some elderly people use both hemispheres equally, thus processing bilaterally.
This has led to two contrasting theories to explain this finding. One theory suggests this change is due to overall functional decline, indicating a malfunction in brain coordination. The other viewpoint posits that the left hemisphere assists the right in compensating for its decline, meaning this situation is a way of making up for the brain’s functional deterioration.
Scientists conducted cognitive tests on older adults aged 60 to 70, selecting two smaller groups: one with high test performance and one with low. They administered the same tests to both groups and a group of young adults aged 20 to 35 while scanning their brains. The results indicated that high-performing older adults used both hemispheres more equally than the other two groups.
The findings support the latter viewpoint, suggesting that bilateral cooperation is a way to compensate for the decline in the right hemisphere due to aging. The next step in research is to determine whether individuals can enhance balanced hemisphere function through training or medication to prevent Alzheimer’s.
Prefrontal cortex: 前额皮质
PET: 性能鉴定 (positron emission tomography)
Alzheimer’s: 老年痴呆症
Compensate: 弥补