The map (to cell resolution!) Of the brain activity of a decision -making process was obtained by studying the brain of mice.
What happens to the individual neurons of our brain when we are engaged in a decision? This was revealed by the first complete mapping of the brain activity at the base of the decision -making processes, built not in a single brain area but in the entire brain (of the mice).
The mastodontic effort, the result of an international collaboration led by the International Brain Laboratory (IBL) of Geneva, Switzerland, allows you to observe the entire process at the basis of a choice at the level of the individual brain cells:
The results, published on Naturethey show that to share the “fatigue” of deciding are, from the beginning, many brain areas that work in a coordinated way, and do not work – as for a long time hypothesized – in a hierarchical and sequential way.
Over half a million neurons
«The map describes the activity of over 650,000 single neurons with single peak resolution. This activity is the basis of the sensory and motor activity of the brain which constitutes a decision.
The map is a fantastic resource, already explored by a myriad of scientists, who is producing unexpected discoveries »explains Matteo Carandini, professor of visual neuroscience at the University College London who took part in the collaboration.
The spatial and temporal resolution of the map is unprecedented and stems from the desire to study the brain activity by combining the skills and technologies of the best neuroscience laboratories of Europe and the United States, in a similar way to what has already been seen in the physics of particles with CERN and in biology with the Human Genome Project.
Instead of studying how the process is unfolded in one or two brain areas at a time, as has always been done in the past, scientists have simultaneously recorded the neural activity of mice in 12 laboratories scattered on the two continents, using tools and ways to process standardized data, that is, equal to all and easily reproducible, while rodents were engaged in the same decision -making task.
This coordinated effort has made it possible to achieve unprecedented precision and extension in mapping:
«We have recorded over half a million neurons on mice in 12 workshops, covering 279 brain areas, which together represent 95% of the cerebral volume of the mouse.
The decision-making activity, and in particular the one linked to the reward, have illuminated the brain as a Christmas tree “says Alexandre Pouget, professor of computational neuroscience at the University of Geneva and co-founder of the Ibl.
Shared dilemma
The mice were placed in front of a screen on which a light was projected, sometimes to the right and sometimes on the left.
The rodents had to move a small wheel in the direction indicated by the light to receive a reward.
Sometimes, however, the light was too weak to be noticed precisely, and the mice had to decide on their own what side to turn the wheel. As expected, the animals were based on the frequency of appearance of light in one or the other dial to decide.
Thus, in addition to studying live how their brain was activated, scientists were also able to study how expectations influence the decision -making process (discovery described in a second article, always on Nature).
Choral work
The experiment showed that the brain signals generated when making a decision are surprisingly well distributed, in the brain, and not located in specific regions:
The brain activity behind our choices would not be organized in a pyramidal way, but instead there would be a constant communication between one area and the other during the decision, the consequent movement and the reward for the choice made.
What discovered will be important in future studies on complex behaviors, which must have a more holistic approach, which looks at a wider picture than what has been done so far. The same Methilodogy will later be applied to the study of other important issues for neuroscience.
The weight of expectations
The second study, on the other hand, demonstrated how expectations are coded not only in the brain areas that regulate cognitive functions, but also in those that control sensory stimuli and actions.
Therefore, if it is true that the brain is a machine to formulate forecasts, it is also true that expectations have an important role in predicting how we will behave. A confirmation that could serve in studies on disorders such as schizophrenia and autism, in which it also seems to play a role in which expectations are coded in the brain.
