Scientists Try to Establish the Limits of the Brain

In a recent press release, Swedish researchers have announced that they have managed to create a mathematical model of the frontal and parietal lobes of the human brain, in a move that they trust will bring forth a new era of knowledge on the cortex, its neurons, and the interactions between them. Experts from the medical university Karolinska Institute (KI) hope to aid doctors understand the seemingly infinite capacities of the working memory, as well as the way in which the billions of neurons interact.

“It's like a computer program for aircraft designers. 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,” KI expert Dr Fredrik Edin, who has a PhD in computational neuroscience, says of the software. “The model predicts, for instance, that increased activation of the frontal lobes will improve working memory. 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.”

The concept of working memory basically refers to the human ability of recording, storing and processing large amounts of data for short periods of time, such as when we are attentive to everything around us, if someone warns us of something. In those moments, the brain exits its usual stand-by-like mode, and pays a lot of attention to what is going on all around. The collected data are stored within the frontal and the parietal lobes, and their presence there helps us think, talk and plan.

By using functional Magnetic Resonance Imaging (fMRI), the researchers have been able to identify which areas of the brain “light up” when working memory is needed, and also to establish the fact that this portion of our brain has a somewhat limited capacity. That is to say, we cannot pay attention to many things at the same time. The actual number of people or actions we can be attentive to at a point naturally varies from individual to individual, but the differences are not statistically relevant.

Employing its “virtual brain,” the team has conducted a series of simulations, trying to find out why the human brain seems unable to keep track of more than 7 images at the same time. The researchers have double-checked their results with fMRI studies carried out on volunteers, and have learned that neurons in the parietal lobe become “heated” when too much information is processed at once, and hinder the activity of cells around them. When the hindering becomes too great, the cells around these neuron clusters lose their ability to record any more visual input, and the limit of the working memory is reached.