Researchers at Karolinska Institutet has shown for the first time identified a cell type in the brain of mice that are central to attention. By manipulating the activity of that particular cell type scientists could sharpen the mice’s attention. The findings, published in the journal Cell, is important for understanding how the front part of the brain functions and controls our behavior.

The forebrain, frontal cortex, has a key role in cognitive brain functions. Among them included mental processes that we constantly use in our daily lives, such as attention, memory, learning, decision making and problem solving. But there is much we do not yet know, for example, the types of neurons that are important for the mental processes.There has long been a theory that parvalbumin-expressing neurons, known as PV cells have a central role in cognition. Now scientists show that PV cells not only appear to be necessary attention. There also appears to be sufficient to optimize the activity of only the PV cells to enhance the attention of mice.

Marie Carlen together with co-author Hoseok Kim.Photo: Stefan Zimmerman.

The researchers focused on the study of attention, because it is a cognitive process that are altered in several neuropsychiatric disorders. They trained the mice to perform a task that requires a high degree of attention.While the animals completed the task again and again, researchers have activity of 100’s of individual nerve cells with electrodes in the frontal cortex of mice.

– We found that the activity of PV cells reflect the animal’s level of attention. The cells had high activity of the animals was attentive and lower activity of the animals was inattentive. The difference was so great that by merely looking at the PV-cell activity for several seconds in advance could predict whether the animal would manage to perform the task or not, said principal investigator Marie Carlen at the Department of Neuroscience.

Used optogenetics

The researchers used optogenetics to affect PV cell activity during the very second the animals have to be alert. Animal attention worsened when the researchers inhibited either PV cell activity or changes in the pattern of cell activity. But the researchers also found a kind of manipulation that could improve attention. In some cognitive processes increases a particular type of brain waves, so-called gamma waves (30-80 Hz), in the prefrontal cortex. When the researchers ran the PV-cell activity in the gamma-speed solved the animals the task more times.

Cognitive problems are common in psychiatric disorders such as schizophrenia, ADHD and autism, but there is currently no effective medicine.

– Our findings linking a variety of previous observations regarding the PV cells in cognition and neuropsychiatric disease, and demonstrates this cell type central role, both in cognition and psychiatry. The findings also show that it is possible to improve cognitive functions by altering the activity of a single type of nerve cell that amazing in light of brain complexity. PV cells is therefore a very interesting target for the pharmaceutical industry, says Marie Carlen.

The research has been done at the Karolinska Institute and funded with grants from the European Research Council (ERC), the Knut and Alice Wallenberg Foundation, the Ragnar Söderberg Foundation and the Brain Foundation.

Text: Karin Söderlund Leifler

Prefrontal parvalbumin Neurons in Control of Attention
Hoseok Kim, Sofie Ährlund-Richter, Xinming Wang, Karl Deisseroth, Marie Carlen Cell, online 14 January 2016, doi: http://dx.doi.org/10.1016/j.cell.2015.11. 038

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