Navigation Links
Computer simulations explain the limitations of working memory

[PRESS RELEASE, 31 March 2009] Researchers at the Swedish medical university Karolinska Institutet (KI) have constructed a mathematical activity model of the brain's frontal and parietal parts, to increase the understanding of the capacity of the working memory and of how the billions of neurons in the brain interact. One of the findings they have made with this 'model brain' is a mechanism in the brain's neuronal network that restricts the number of items we can normally store in our working memories at any one time to around two to seven.

Working memory, which is our ability to retain and process information over short periods of time, is essential to most cognitive processes, such as thinking, language and planning. It has long been known that the working memory is subject to limitations, as we can only manage to "juggle" a certain number of mnemonic items at any one time. Functional magnetic resonance imagery (fMRI) has revealed that the frontal and parietal lobes are activated when a sequence of two pictures is to be retained briefly in visual working memory. However, just how the nerve cells work together to handle this task has remained a mystery.

The study, which is published in the journal PNAS, is based on a multidisciplinary project co-run by two research teams at KI led by professors Torkel Klingberg and Jesper Tegnr. Most of the work was conducted by doctors Fredrik Edin and Albert Compte, the latter of whom is currently principal investigator of the theoretical neurobiology group at IDIBAPS in Barcelona.

For their project, the researchers used techniques from different scientific fields, applying them to previously known data on how nerve cells and their synapses function biochemically and electrophysiologically. They then developed, using mathematical tools, a form of virtual or computer simulated model brain. The computations carried out with this 'model brain' were tested using fMRI experiments, which allowed the researchers to confirm that the computations genuinely gave answers to the questions they asked.

"It's like a computer programme for aircraft designers," says Fredrik Edin, PhD in computational neuroscience. "Before testing the design for real, you feed in data on material and aerodynamics and so on to get an idea of how the plan's going to fly."

With their model brain, the team was able to discover why working memory is only capable of retaining between two and seven different pictures simultaneously. As working memory load rises, the active neurons in the parietal lobe increasingly inhibit the activity of surrounding cells. The inhibition of the inter-neuronal impulses eventually becomes so strong that it prevents the storage of additional visual input, although it can be partly offset through the greater stimulation of the frontal lobes. This leads the researchers to suggest in their article that the frontal lobes might be able to regulate the memory capacity of the parietal lobes.

"The model predicts, for instance, that increased activation of the frontal lobes will improve working memory," continues Dr Edin. "This finding was also replicable in follow-up fMRI experiments on humans. Working memory is a bottleneck for the human brain's capacity to process information. These results give us fresh insight into what the bottleneck consists of."


Contact: Katarina Sternudd
Karolinska Institutet

Related biology news :

1. Computer superpower strengthens attempts to combat common diseases
2. New open-source software permits faster desktop computer simulations of molecular motion
3. Lifecycles of tropical cyclones predicted in global computer model
4. Singapore research team first place in Brain-Computer Interface contest
5. ORNL supercomputer simulation wins prize for fastest-running science application
6. Oak Ridge supercomputer is the worlds fastest for science
7. Supercomputer provides massive computational boost to biomedical research at TGen
8. Could Dr. House be replaced by a computer?
9. San Diego Supercomputer Center and UCSD announce Triton Resource
10. New data resource to advance computer-aided drug design
11. Coming soon: Self-guided, computer-based depression treatment
Post Your Comments:
(Date:11/19/2015)...  Based on its in-depth analysis of the biometric ... the 2015 Global Frost & Sullivan Award for Product ... this award to the company that has developed the ... the market it serves. The award recognizes the extent ... customer base demands, the overall impact it has in ...
(Date:11/17/2015)... Paris , qui ... Paris , qui s,est tenu du ... leader de l,innovation biométrique, a inventé le premier scanner ... sur la même surface de balayage. Jusqu,ici, deux scanners ... les empreintes digitales. Désormais, un seul scanner est en ...
(Date:11/12/2015)... , Nov. 12, 2015  Arxspan has ... of MIT and Harvard for use of its ... information management tools. The partnership will support the ... biological and chemical research information internally and with ... be used for managing the Institute,s electronic laboratory ...
Breaking Biology News(10 mins):
(Date:11/24/2015)...  Clintrax Global, Inc., a worldwide provider of clinical research services ... that the company has set a new quarterly earnings record in ... growth posted for Q3 of 2014 to Q3 of 2015.   ... , with the establishment of an Asia-Pacific ... United Kingdom and Mexico , ...
(Date:11/24/2015)... ... 24, 2015 , ... The Academy of Model Aeronautics (AMA), led by its ... as Multirotor Grand Prix, to represent the First–Person View (FPV) racing community. , FPV ... embraced this type of racing and several new model aviation pilots have joined the ...
(Date:11/24/2015)... 2015  Tikcro Technologies Ltd. (OTCQB: TIKRF) today announced that its Annual ... 11:00 a.m. Israel time, at the law offices ... Street, 36 th Floor, Tel Aviv, Israel . ... and Izhak Tamir to the Board of Directors; , ... , approval of an amendment to certain terms of options granted ...
(Date:11/24/2015)... ... November 24, 2015 , ... In ... paramount. Insertion points for in-line sensors can represent a weak spot where leaking ... 781/784 series of retractable sensor housings , which are designed to tolerate extreme ...
Breaking Biology Technology: