The cerebellum plays a more important role in human thought than we previously suspected: gunshots

An old part of the brain, long ignored by the scientific world, seems to play a crucial role in everything from language and emotions to daily planning.

It is the cerebellum, which is found in fish, lizards and humans.

But in the human brain, this structure is connected to areas involved in higher thinking, a team led by researchers at the University of Washington in St. Louis said Thursday. Neuron.

"We believe that the cerebellum is the ultimate quality control unit of the brain," says Scott Marek, a postdoctoral researcher and first author of the study.

The discovery adds to the growing evidence that the cerebellum "is not just about sensorimotor function, it's involved in everything we do," says Dr. Jeremy Schmahmann, professor of neurology at Harvard and director of the Ataxia Treatment Unit at Massachusetts General. Hospital.

Schmahmann, who has not been involved in the new study, has been arguing for decades that the cerebellum plays a key role in many aspects of human behavior, as well as in psychiatric disorders such as schizophrenia.

But only a handful of scientists have explored the functions of the cerebellum beyond motor control.

"She has been terribly misunderstood," said Dr. Nico Dosenbach, a professor of neurology at the University of Washington, whose lab conducted the study.

Even now, many scientists believe that the cerebellum is the part of the brain that allows you to pass a roadside sobriety test. It helps you do things like walking in a straight line, standing on one leg or following a moving object, if you are not drunk.

But the University of Washington team thought there was a lot going on in that part of the brain. They used a special type of MRI to study the cerebral cabling of 10 people.

This allowed the team to quantify the different connections between the cerebellum and other areas of the brain. And they discovered that only 20% of the cerebellum was devoted to areas related to physical movement, while 80% were devoted to areas such as abstract thinking, planning, emotions, memory, and language.

"We already thought that the cerebellum was colder than most people thought," says Dosenbach. "But these results were much more exciting and clear than I could have ever dreamed of."

The cerebellum does not directly perform tasks such as thinking, just as it does not directly control movement, explains Marek. Instead, he says, this seems to monitor the areas of the brain that are doing the work and make them perform better.

In essence, this structure seems to act as a kind of publisher, constantly revising and improving a person's thoughts and decisions, says Dosenbach. If this is true, he says, it is not surprising that alcohol affects more than our physical movements.

"We have an explanation for all the bad ideas that people have when they are drunk," he says. "They lack cerebellar revisions of your thoughts."

The new study suggests how the cerebellum has evolved over hundreds of millions of years, says Schmahmann.

"What has happened over time is that the cerebellum has grown enormously," he says. And this extra capacity allowed him to take on functions beyond the movement.

But the way the cerebellum works has not changed, says Schmahmann. This makes the process smoother, faster and more accurate. "What we understand now is that what the cerebellum does for motor control, it does it for cognition and emotions as well."

And the cerebellum does it all automatically, allowing our conscious mind to focus on more important things, says Schmahmann.

But when the cerebellum does not do its job, says Schmahman, the result could be a brain disorder.

"There is more and more evidence in a variety of areas now that autism spectrum psychiatric illness, schizophrenia, depression, obsessive-compulsive disorder, all have a connection with the cerebellum," he said. he.

Schmahmann and a few other researchers have therefore begun to try to treat patients with some of these problems by improving the function of this ancient structure in the brain.