[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 al
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