Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Brain’s ’daydream’ network offers detection for Alzheimer’s diagnosis

26.11.2003


Researchers tracking the ebb and flow of cognitive function in the human brain have discovered surprising differences in the ability of younger and older adults to shut down a brain network normally active during periods of passive daydreaming. The differences, which are especially pronounced in people with dementia, may provide a clear and powerful new method for diagnosing individuals in the very early stages of Alzheimer’s disease.



"In young adults, there are parts of the brain that are very active during a passive free-thinking state, but these areas appear to shut down dramatically or ’turn off’ when the person is asked to do something," said Cindy Lustig, research team member and post-doctoral fellow in psychology at Washington University in St. Louis. "Interestingly, older people, especially those with Alzheimer’s disease, don’t show this same kind of brain activity during free- thinking, resting conditions."

In a study published Nov. 25 in the Proceedings of the National Academies of Science, Lustig and colleagues detail results of functional magnetic resonance imaging (fMRI) tests conducted on groups of young adults, older adults and adults experiencing early signs of Alzheimer’s-related dementia.


Although fMRI testing is widely used to track regional increases in brain activity during completion of specific mental tasks, such as language, memory or problem solving, this study focuses on what happens in regions that are active when the brain has no particular task at hand, regions that are focal points for a baseline, passive processing mode, one that seems to operate when the mind free to wander and daydream.

"What we found in our study is that rather than turning these regions off when asked to concentrate, as young adults do, people with Alzheimer’s seem to turn them on," Lustig said. "This might reflect a ’broken brain’ in Alzheimer’s, making it hard for people to turn these brain regions on or off appropriately; more optimistically, it might be an attempt to compensate for the memory problems that come with Alzheimer’s."

Other members of the Washington University in St. Louis / Howard Hughes Medical Institute research team include Abraham Z. Snyder, Mehul Bhakta, Katherine O’Brien, Mark McAvoy, Marcus E. Raichle, John C. Morris and Randy L. Buckner, all of whom are affiliated with the departments of psychology in Arts and Sciences and/or the departments of neurology and radiology in the School of Medicine.

Raichle, a pioneer in the use of positron emission tomography (PET) to image changes in brain activity, has been an advocate for more research into brain deactivations, a process by which the brain reduces activity in one region so that resources can be shifted to other areas where more challenging mental tasks are currently being processed. Irregularities in brain deactivation patterns have been noted in other neurological illnesses, including amnesia, schizophrenia and Fragile X syndrome.

Recent research has provided mounting evidence supporting the existence within the brain of a "default network," a set of interconnected brain areas that carry out routine, passive mental processes, such as monitoring the environment, registering internal emotions and other forms of largely undirected thought and reflection. Brain areas thought to be included in this network are the medial frontal, the lateral parietal and the posterior cingulate regions of the cortex.

"The posterior cingulate cortex was the site of the largest and most intriguing differences between the groups," Buckner said. "Whereas young adults showed decreases in this region after a transient initial activation, Alzheimer’s participants maintained an above-baseline activation throughout the task period."

The study also identified a number of other significant differences in the timing and magnitude of changes in default network activity among young adults, older adults and older adults with early stages of Alzheimer’s.

Other studies have shown that young adults have more activity in this default network than do older adults during so-called passive conditions where they are not given any particular task to think about. What this new study found is that older adults also do not seem to shut down or "deactivate" the default network as much when they are given something to concentrate on.

"The reduced deactivation in the older adult groups are especially surprising, given that the performance data suggested that they found the task more difficult than did the young adults, " Buckner noted. "In young adults, greater task difficulty is usually associated with greater deactivation in these areas."

Interestingly, there is one situation in which young adults exhibit some activity in the default or daydreaming regions even while they are actively tackling a mental task elsewhere in the brain; that is when the task at hand involves a person’s autobiographical memory. For instance, if someone asks what you had for breakfast or how you feel about something that happened in your past, then you might activate parts of the default passive processing network as you search for the answer.

"Since the brain’s default processing network is connected to brain areas that are heavily involved with memory, it could be that people with memory problems are turning the network on in an attempt to compensate for the memory damage caused by normal aging or Alzheimer’s," Lustig said.

"The biggest, most obvious thing that we know about these default regions is that older adults, especially those with Alzheimer’s, are doing something different with them when they’re in a free-thinking mode. The reasons for this aren’t entirely clear, but may have something to do with their memory problems.

"In the long run, this quirk may help us understand what’s going wrong with fundamental cognitive processes that underlie mental declines associated with aging and Alzheimer’s. In the meantime, we’re very interested in whether these changes can be used to identify older adults in the earliest stages of Alzheimer’s disease so that they can begin treatment as soon as possible."

Gerry Everding | EurekAlert!
Further information:
http://www.wustl.edu/

More articles from Health and Medicine:

nachricht Millions through license revenues
27.04.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>