The human brain uses different regions to process information, such as memory, sensory input, or even one’s own internal thoughts. The variety of regions are linked by a network of white matter conduits. The question is if aging degrades the white matter that links the different regions of the brain and what effect it has on a person’s cognitive ability even in the absence of a serious disease like Alzheimer’s.
Researchers at the Howard Hughes Medical Institute studied 93 people divided roughly into 2 groups; the young adult (18-34) and the older adult (60-93). Using a functional magnetic resonance imaging (fMRI) to precisely map enhanced blood flow in specific regions of the brain the participants were presented words and asked to decide whether each word represented a living (e.g. dog) or nonliving (e.g. house) object. This simple task required the participants to meaningfully process the words.
The young adults showed that the front of the brain was ‘in sync’ with the back of the brain. In older adults there were signs that the white matter conduits were compromised. As a result the different regions became out-of-sync and they were less correlated with each other. Older adults who tested well on the cognitive test also showed normal synchronization between the front and rear regions of the brain.
Change in the brains of individuals in their 70s & 80s is expected. This study can help better understand the cognitive decline in the elderly and why some individuals remain sharp into their 90s.