Memories of the future

For the brain, remember the past and visualize the future looks surprisingly similar.

In the story Alice lost in fairyland, when Alice climbed through the observation glass, she encountered an inverse world. People are punished before committing crimes, and sometimes blood flows before the needle stabs. These events reflect memory that works both ways in that world, allowing people to remember things before they happen. As the Queen explained to Alice that 'It is a pitiful memory that only works backwards.'

Now, back in the present world, scientists discover that human memory really works forward. More and more research proves that the mental mechanism of resurrecting memories performs another task - perhaps more necessary - to envision the future.

Other works show that dementia people completely present 'white space' when asked about their own future. And people with severe depression, who often think of both the past and the future in an indeterminate direction, have trouble figuring out positive future events.

Similar findings prompted scientists to rethink the role of memory. Instead of seeing it as merely a storehouse of reality and personal data, researchers gradually realized that memory also created, reproduced, and predicted future events that might occur in the environment. constantly changing. Some argue that perhaps this kind of memory itself exists specifically for this purpose.

According to psychologist Kathleen McDermott, Washington University, St. Louis, 'Not quite clear what we have memory to do from the beginning. The idea of ​​sitting back and remembering the peanut we eat yesterday doesn't seem to have a clear and convincing adaptive value. '

But if it is the ability to visualize and thus adjust a better future, the evolutionary usefulness of memory suddenly becomes clear.

Harvard University psychologist Daniel Schacter agrees and adding the reverse role of memory can help explain why the human memory system is designed today. Recall personal memories and imagine the future can use the same neurological mechanisms. Schacter co-hosted a presentation on this topic in Boston, during the annual meeting of the Community for American Science Progress this year.

Many similar brain regions are used to recall vivid memories (left) in the process of creating and generating future events (right).Functional magnetic resonance imaging reveals extensive overlapping in memory areas and planned networks.(Photo: D.Schacter)

Although current research focuses on episodes of memory, or memory of events, times, places, and Schacter that show other types of memory such as memory of words and general knowledge, no doubt What, also involves thinking about the future. 'Intelligence memory seems important when people think about their personal future because it is the source for details that allow people to reconstruct what might happen.'

Relive memories

For more than a century, memory research scientists have focused on its role in retaining and restoring the past. Finally, the neurological nuances of memory are mapped primarily to the hippocampus and the prefrontal cortex.

In the early 1980s, researchers identified additional areas in anticipation and anticipation. Studies of patients with brain damage show that they struggle with these activities as well as remember the past. At that time, Endel Tulving, a psychologist at the University of Toronto, doubted that mental capacity allowed people to recall past episodes, such as disagreements with customers, and also created the ability to foresee. possible future, such as planning for an upcoming meeting with that customer.

Schacter, a graduate student at Tulving's lab at the time, was impressed by a patient named KC A motorbike accident that hurt KC's hippocampus Although he retained some general knowledge about In the world, he cannot recall his own memories. When asked what he would do next week, KC had a hard time reacting. Schacter said 'It is just an unorthodox form of observation but it always surprises me.'

Three years ago, when studying why memory might not be reliable, Schacter thought about KC's inability and hypothesized: Perhaps the overlap between memory and imagination could be explained. by the 'creation' nature of memory. Instead of pulling out a file like a computer, the memory who crisscrossed all of the petty debris together - place, people, sounds - needed to reconstruct a plot. The flexible system, which follows each of these parts, can cause memory to make mistakes but also provides a way to gather information from the past to prepare for future challenges.

At that time, only one photo study was performed to test the general areas of the brain that were common to thinking about the future or recalling the past. By using a more systematic method, Schacter explained that he could point out the components involved in both of these activities.

Using functional magnetic resonance imaging (fMRI) to capture brain activity patterns, Schacter tested its hypothesis by examining the overlap of brain regions used in recall and imagination. . In this study, 14 participants described a series of their past events involving a common object, such as a table. These same people then envision a future that could happen to that object.

In the early stages of creating an event, the left hippocampus is active in remembering and imagining. The most obvious overlap is in the 'arising period', when participants give details for the event. In addition, certain areas of the hippocampus must become active when participants imagine a future event, but do not work when they recall the past. Schacter says these activities can reflect the detailed filtering process from countless past events to a new fantasy detail.

Let the imagination work

Schacter's results were confirmed last year when McDemott, along with PhD student Karl Szpunar, published another MRI work in the Proceedings of the National Academy of Sciences. In this work, participants were given a detail, such as a birthday party, and were instructed to recall a personal event in their lives and recall as vividly as possible in 10 seconds. In the second condition, they think of a personal event and visualize it in the future. Then they envisioned a 3rd event, putting an acquaintance (not themselves) into the future.

The brain activity model of past and future events looks the same only when participants imagine themselves in the future picture. When visualizing the future of a third person, similar regions are also busy but not at the same level.

A serial project demonstrates that subjects report back to a more vivid visualization imagining events that may occur in the near future, or in familiar circumstances. Again, brain regions used in thinking about the future and recalling the past are almost indistinguishable.

'We have a headache about this for a while. Whatever happens when we remember the past, the same thing happens when we envision the future. '

These results corroborate the idea that personal profile information is used not only to recall, but also to build up images of future events. 'The only difference is that people almost filter information from the past and relate it in a different way to think about what might happen in the future.'

He and his team recently pointed out that a hippocampus in the back is used to create and generate past and future events. This finding suggests that this region may be where memory is 'grabbed' during the construction process, according to Schacter and his reporter in Hippocampus in February.

Stand beside

Schacter and postdoctoral researcher Donna Addis hypothesized the "deductive plague simulation" theory last year in a Nature paper. At the same time, another project also relates to the future memory of Eleanor Maguire and colleagues at the Wellcome Trust Center for Neuroimaging, University of London. Maguire requires 5 people to lose their imagination and then describe in detail situations in familiar situations such as beaches, pubs and markets. These patients are also required to describe future events, such as a Christmas party.

Although it has been suggested to help revisit their memories, patients cannot connect the elements together to become an imaginary event. Instead of visualizing a single scene in the mind, such as a beach full of sunbathers, the patients reported seeing only a set of discrete images, such as sand, water, and children. people and beach towels.

Patients seem to lack a 'spatial context' to place events there. Maguire says ' Events in your life happen in a specific place - a shop, at work or in a room of your home. These patients simply don't have that kind of context to pull out their memories. '

Maguire said the results show that the hippocampus region specifically plays a role in helping people connect event debris to create both past and future scenes.

To study and gain more details about the mechanism behind the spatial context, Maguire and colleagues recently returned to the scanner. This time, scientists compare real and imaginary memories to see which other brain regions (if any) are activated in each situation.

'Our argument is that if we can compare real memories with imaginary, fictional memories, it may allow us to identify areas of the brain related to ourselves, with time travel. spiritual space and with the feeling of something really happening. Because true memories have all these characteristics, and the imaginary event doesn't have any of these characteristics. '

The study revealed a core network of brain regions - including hippocampus, parahippocampal gyrus and retrosplenial cortex - the foundation of the emergence and maintenance of a complex, coherent setting in both real and imagine. According to Maguire, the core network of these brain regions seems to underlie the process of creating important scenes in such sequence of events.

She argued that the creation of this scene is an important part of reminiscing past memories in the memory process, including orientation, planning for the future, dreaming and rambling thoughts.

'We think to create a support scene not only for spatial memory and personal biography and imagination, but also for other key cognitive functions.' This includes word memory, polygon information, short-term and long-term memory.

Her findings, published in the December issue of the Journal of Neuroscience, also reveal areas of the brain that help distinguish true and imaginary memories. Maguire said that these regions, including cortex and posterior cingulate cortex, seem to be co-opted into the network to create scenes when the subject recalls real memories.

'Memories happen to you, extremely vivid memories, there are very specific things that help you distinguish them from imaginary memories or things that may or may not happen in the future. If you take the creation of the future as the center, you may need other processes above it to get the feeling that this is the true memory that happens to you. '

Applications for imagining the future

Maguire and his colleagues are continuing to work on finding the neurological foundation for scene creation. Other scientists are investigating how the memory system contributes to memory decline in aging, depression, Alzheimer's disease and head injury.

By understanding how this memory system works - what each part does and what brain areas are involved - scientists can develop ways to cure memory-related diseases.

Ongoing research may also provide new knowledge about other functions of memory when it comes to future-oriented thinking, such as planning, predicting, and recalling plans. .

Despite recent developments, Maguire says scientists are far from understanding how the different brain components of memory talk to each other and interact to reproduce future events. .

'We are still at the stage of trying to understand how these wonders happen.'