For years, conventional wisdom held that growing older tends to be bad news for brains. Past behavioral data largely pointed to loss in cognitive – that is, thinking – abilities with age, including poorer memory and greater distractibility. Physical measures of brain structure also showed atrophy, or loss of volume, in many regions with age.
Watching Older Brains at Work
Enter cognitive neuroscience, a subfield of psychology that incorporates methods from neuroscience. It uses measures of brain activity to understand human thought. The emphasis is on how the brain shapes behavior, asking questions like which brain regions help us form accurate memories or what area controls face perception.
Using cognitive neuroscience methods to study aging has unexpectedly revealed that, contrary to previous thought, aging brains remain somewhat malleable and plastic. Plasticity refers to the ability to flexibly recruit different areas of the brain to do different jobs. In contrast to the earlier, largely pessimistic view of aging, neuroimaging studies suggest aging brains can reorganize and change, and not necessarily for the worse.
Researchers investigate which parts of the brain are engaged during different tasks using methods such as functional magnetic resonance imaging, which measures blood flow to various areas of the brain while active. By tracking what happens inside the brain during particular activities, neuroimaging data reveal patterns of change with age. For instance, older adults sometimes use a region in both the left and right hemispheres of their brains to perform certain tasks, while young adults engage the region in only one half of the brain. Older adults also appear to activate more anterior regions of the brain whereas young adults exhibit more posterior activation.
The emergence of the cognitive neuroscience of aging occurred alongside advances in the understanding of neurogenesis; neuroscientists discovered that the growth of new neurons could continue throughout life, not just when we are very young. It is still unknown to what extent new neurons contribute to behavioral and brain changes with age. But there is some evidence in rodents that new learning and enriched, stimulating environments increase survival of new neurons potentially allowing the new neurons to contribute to abilities and even improve health.
External Stimulation
