Friday, March 11, 2011

Psychologists Use fMRI To Understand Ties Between Memories And The Imagination

July 1, 2007 — Psychologists have found that thought patterns used to recall the past and imagine the future are strikingly similar. Using functional magnetic resonance imaging to show the brain at work, they have observed the same regions activated in a similar pattern whenever a person remembers an event from the past or imagines himself in a future situation. This challenges long-standing beliefs that thoughts about the future develop exclusively in the frontal lobe.

Remembering your past may go hand-in-hand with envisioning your future! It's an important link researchers found using high-tech brain scans. It's answering questions and may one day help those with memory loss.

For some, the best hope of 'seeing' the future leads them to seek guidance -- perhaps from an astrologist. But it's not very scientific. Now, psychologists at Washington University are finding that your ability to envision the future does in fact goes hand-in-hand with remembering the past. Both processes spark similar neural activity in the brain.

"You might look at it as mental time travel--the ability to take thoughts about ourselves and project them either into the past or into the future," says Kathleen McDermott, Ph.D. and Washington University psychology professor. The team used "functional magnetic resonance imaging" -- or fMRI -- to "see" brain activity. They asked college students to recall past events and then envision themselves experiencing such an event in their future. The results? Similar areas of the brain "lit up" in both scenarios.

"We're taking these images from our memories and projecting them into novel future scenarios," says psychology professor Karl Szpunar.

Most scientists believed thinking about the future was a process occurring solely in the brain's frontal lobe. But the fMRI data showed a variety of brain areas were activated when subjects dreamt of the future.

"All the regions that we know are important for memory are just as important when we imagine our future," Szpunar says.

Researchers say besides furthering their understanding of the brain -- the findings may help research into amnesia, a curious psychiatric phenomenon. In addition to not being able to remember the past, most people who suffer from amnesia cannot envision or visualize what they'll be doing in the future -- even the next day.

BACKGROUND: Researchers from Washington University in St. Louis have used advanced brain imaging techniques to show that remembering the past and envisioning the future may go hand-in-hand, with each process showing strikingly similar patterns of activity within precisely the same broad network of brain regions. This suggests that envisioning the future may be a critical prerequisite for many higher-level planning processes in the brain.

WHAT IS fMRI: Magnetic resonance imaging (MRI) uses radio waves and a strong magnetic field rather than X-rays to take clear and detailed pictures of internal organs and tissues. fMRI uses this technology to identify regions of the brain where blood vessels are expanding, chemical changes are taking place, or extra oxygen is being delivered. These are indications that a particular part of the brain is processing information and giving commands to the body. As a patient performs a particular task, the metabolism will increase in the brain area responsible for that task, changing the signal in the MRI image. So by performing specific tasks that correspond to different functions, scientists can locate the part of the brain that governs that function.

ABOUT THE STUDY: The researchers relied on fMRI to capture patterns of brain activation as college students were given 10 seconds to develop a vivid mental image of themselves or a famous celebrity participating in a range of common life experiences. Presented with a series of memory cues -- such as getting lost, spending time with a friend, or attending a birthday party -- participants were asked to recall a related event from their own past; to envision themselves experiencing such an event in their future life; or to picture a famous celebrity (specifically, former U.S. president Bill Clinton) participating in such an event.

WHAT THEY FOUND: Comparing images of brain activity in response to the 'self-remember' and 'self future' event cues, researchers found a surprisingly complete overlap among regions of the brain used for remembering the past and those used for envisioning the future. The study clearly demonstrates that the neural network underlying future thoughts is not only happening in the brain's frontal cortex. Although the frontal lobes play an important role in carrying out future-oriented operations -- such as anticipation, planning and monitoring -- the spark for these activities may be the process of envisioning yourself in a specific future event. And that's an activity based on the same brain network used to remember memories about our own lives. Also, patterns of activity suggest that the visual and spatial context for our imagined future is often pieced together using our past experiences, including memories of specific body movements: data our brain has stored as we navigated through similar settings in the past.

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

Note: This story and accompanying video were originally produced for the American Institute of Physics series Discoveries and Breakthroughs in Science by Ivanhoe Broadcast News and are protected by copyright law. All rights reserved.

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