A study by neuroscientists from Duke University Medical Center reveals differences in how older and younger people use their brains when it comes to storing memories, particularly those associated with negative emotions.
Older adults, average age 70, and younger adults, average age 24, were shown a series of 30 photographs while their brains were imaged in a functional MRI (fMRI) machine. Some of the photos were neutral in nature and others had strong negative content such as attacking snakes, mutilated bodies and violent acts.
While in the fMRI machine, the subjects viewed the photos and ranked them on a pleasantness scale. Following that they completed an unexpected recall task following the fMRI scan to determine whether the brain activity that occurred while looking at the pictures could predict later memory. The results were sorted according to the numbers of negative and neutral pictures that were remembered or missed by each group.
The scientists believe that the study showed that the older adults have less connectivity between an area of the brain that generates emotions and a region involved in memory and learning. But they also found that the older adults have stronger connections with the frontal cortex, the higher thinking area of the brain that controls these lower-order parts of the brain.
“The younger adults were able to recall more of the negative photos,” said Roberto Cabeza, Ph.D., senior author and Duke professor in the Center for Cognitive Neuroscience. If the older adults are using more thinking than feeling, “that may be one reason why older adults showed a reduction in memory for pictures with a more negative emotional content.”
“It wasn’t surprising that older people showed a reduction in memory for negative pictures, but it was surprising that the older subjects were using a different system to help them to better encode those pictures they could remember,” said lead author Peggy St. Jacques, a graduate student in the Cabeza laboratory.
Young adults employed more of the brain regions usually involved in emotion and recalling memories.
The emotional centers of the older subjects were as active as those of younger subjects — it was the brain connections that differed.
There are various possibilities as to why there are these differences.
Older people have more visual memories of unpleasant images, such as snakes, than younger ones. This is especially true for the current generations thanks to photography, film and video access that other generations lacked.
“If using the frontal regions to perform a memory task was always beneficial, then the young people would use that strategy, too,” Cabeza said. “Each way of doing a task has some trade-offs. Older people have learned to be less affected by negative information in order to maintain their well being and emotional state – they may have sacrificed more accurate memory for a negative stimulus, so that they won’t be so affected by it.”
Another possibility is that an older person looks at something to decide what to do with or about it; the brain may not remember it as well since keeping the information is irrelevant. What is relevant is the response to it.
Why remember what is already largely remembered in previously stored visual memories that pose no possible current danger?
Young people are still visually (and in other ways) learning about the world. Thus their responses would be different from an older person’s.
Healthy normal brains use visual memories to decode the impressions of light received from the eyes. Only ten percent of the process of visual perception occurs in the eyes, which see impressions of light. The bulk of visual work happens in the brain as it decodes the information received from the eyes by using memories of visual experiences that seem to compare to the current impressions of light.
At some point the brain has enough visual memories of a specific person, place or thing so unless there is a change – an update — it eases off on collecting more. Top brands understand this so the slightly change their packaging, which gets them attention, otherwise a product is actually see, but not “noticed” as no update is needed.
My personal experience with consciously creating new visual memories of energy and helping other do so also come from my work as an artist. As the founder of Post Conceptual UnGraven Image Art Theory, I work to create works that show the energy, the essences that are the building blocks of the physical universe.
When a person has enough visual memories of my art, they begin actually experiencing seeing more of the energy that is everywhere always. Our eyes see this energy, but until now, our brains have had no way to decode these perceptions. This new way of seeing was discovered as the works changed my visual experience, allowing me to see more energy, everywhere, always and now.
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When older people made more stronger connections with the frontal cortex they were deciding what to do about the visual stimuli rather than what to do with it. Older people also have more experience with seeing photographs and images.
Younger people are still discovering reality and who they are. This is why younger people flock to Horror and Action pictures that can take a hefty amount of suspended belief (or the ability to pretend), while older people enjoy other fare with more emotional and perceptual nuances.
“Perhaps at different stages of life, there are different brain strategies,” Cabeza speculated. “Younger adults might need to keep an accurate memory for both positive and negative information in the world. Older people dwell in a world with a lot of negatives, so perhaps they have learned to reduce the impact of negative information and remember in a different way.” According to Cabeza, the results of the study are consistent with a theory about emotional processes in older adults proposed by Dr. Laura Carstensen at Stanford University , an expert in cognitive processing in old age.
“One thing we might do in the future is to ask subjects to try to actively regulate their emotions as they look at the pictures,” St. Jacques said. “Would there be a shift in the neural networks for processing the negative pictures when we asked younger people to regulate their emotional responses? How would that affect their later recall of the negative pictures?”
The study appears in the January issue of Psychological Science.
Some of the material in this article is adapted from a news release issued by the Duke University Medical Center .
Tags: brain, Duke University, emotion, memory, mental function, neuroscience, old brain, vision, young brain
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