Nutriovia

Consciousness can be a mystery, but that does not mean that neuroscientists have no explanation. Far from it.

“In the field of conscience, there are already so many theories that we do not need more theories,” said Oscar Ferrante, neuroscientific of the University of Birmingham.

If you are looking for a theory to explain how our brains give birth to subjective inner experiences, you can consult the theory of adaptive resonance. Or consider the dynamic theory of the nucleus. Do not forget the theory of representation of the first order, not to mention the theory of the semantic pointer competition. The continuous list: an identified 2021 survey 29 different theories of consciousness.

Dr. Ferrante belongs to a group of scientists who want to reduce this number, perhaps even one. But they are confronted with a steep challenge, thanks to the way in which scientists often study consciousness: to conceive a theory, to perform experiences to build evidence and to affirm that it is better than the others.

“We are not encouraged to kill our own ideas,” said Lucia Melloni, a neuroscientist of the Max Planck Institute for Empirical Aesthetics in Frankfurt, Germany.

Seven years ago, Dr. Melloni and 41 other scientists launched a major study on the consciousness that she hoped would break this model. Their plan was to bring together two rival groups to design an experience to see to what extent the two theories have predicted what is happening in our brain during conscious experience.

The team, called consortium cogitate, published Its results Wednesday in the journal Nature. But along the way, the study has become subject to the same strong conflicts to avoid.

Dr. Melloni and a group of scientists sharing the same ideas began to develop plans for their study in 2018. They wanted to try an approach known as an adversary collaboration, in which scientists with opposing theories unite their forces with neutral researchers. The team has chosen two theories to test.

One, called a global neural workspace theory, was developed in the early 2000s by Stanislas Dehaene, a cognitive neuroscientist of the Collège de France in Paris and his colleagues. Their theory argues that we consciously feel the world when key regions in front of the brain have disseminated sensory information all over the brain.

The other theory, developed by Giulio Tononi of the University of Wisconsin and his colleagues, bears the name of the integrated information theory. Instead of attributing an awareness to particular parts of the brain making particular things, this theory begins with the fundamental characteristics of conscious experiences: they feel specific to ourselves, for example, and they are rich in details which form a coherent, complex and unified whole – like Marcel Proust’s experience of memories that flooded when he nibbled a madeleine.

The researchers then asked what type of physical network – a brain or other – could produce this experience. They concluded that he must involve the processing of a lot of information in many different compartments, which then transmit information to other compartments, creating an integrated experience.

The cogitate consortium has cartographed an experience This could put the two theories to the test. The champions of the two theories approved it.

“It was particularly pleasant, because it was the first time that these people have tried to resolve their disagreements instead of simply making this parallel piece,” said Dr. Melloni.

But she and her colleagues knew that contradictory collaboration would be a huge company. They recruited a certain number of young researchers, including Dr Ferrante, then spent two years designing experience and putting their laboratory equipment through tests. From the end of 2020, they started scanning the brain of 267 volunteers, working in eight laboratories in the United States, Europe and China.

The researchers asked volunteers to play video games designed to measure their awareness of seeing things. In one of these games, the participants caught colorful discs when they took place. Sometimes a blurred face also dried through the screen, and the volunteers pressed a button to indicate that they noticed it.

For a maximum understanding, the researchers used three different tools to measure the brain activity of volunteers.

Some volunteers, who underwent surgery for epilepsy, agreed to have electrodes temporarily inserted in their brain. A second group caused their brains to scan by irmf machines, which measured the flow of blood in their brain. The researchers studied a third group with Magnetotephalography, which records the magnetic fields of a brain.

By 2022, researchers were devoted to the analysis of their data. The three techniques provided the same overall results. The two theories have made precise predictions on what was going on in the brain as subjects experienced images consciously. But they also made predictions that have proven to be wrong.

“The two theories are incomplete,” said Dr Ferrante.

In June 2023, Dr. Melloni revealed The results at a conference in New York. And COGITATE Consortium published online results and submitted them to nature, hoping that the journal would publish its article.

Hakwan Lau, a neuroscientist from Sungkyunkwan University who was invited to serve as one of the examiners, rendered a negative judgment. He considered that the cogitate consortium had not carefully arranged exactly where in the brain, he would test the predictions of each theory.

“It is difficult to be convinced that the project really tests theories significantly,” wrote Dr. Lau in his July review.

Dr. Lau, who was the pioneer A theory of his consciousnessposted her assessment Online in August. He then helped write an open letter criticizing both the cogitate experience and the integrated information theory. A total of 124 experts signed it.

The group, which was called “Iit-Concerned”, directed a large part of its criticisms on the integrated information theory. They called him pseudoscience, citing withered attacks that scientists have done on theory in recent years.

These criticisms noted that the integrated information theory is much more than a theory on the functioning of our brain: if a system that can integrate information is conscious, then plants could even be aware, at least a little.

The experience of consortium cogitate has not lived up to its assertions, supported criticism because it did not test the fundamental aspects of theory. “As researchers, we have a duty to protect the public from scientific disinformation,” wrote Dr. Lau and his colleagues.

Their letter, poster Online in September 2023, led to a storm of debate on social networks. The authors wrote a comment to explain their objections in more detail; he appeared Last month in the journal Nature Neuroscience.

Dr. Tononi and his colleagues responded in the newspaper with a retort. The letter from CIIT “had a lot of fervor and little in fact”, they wrote, and the new comment “tries control of damage by adding a varnish and a passage philosophy of science.”

Meanwhile, the Cogitate Consortium Journal was still making its way through peer exam. When he finally released on Wednesday, he continued to attract divided opinions.

Anil Seth, a neuroscientist of the University of Sussex, was impressed by the study scale and its discovery of gaps in each theory. “I am delighted to see him,” he said. “It’s a great job.”

But the criticisms of the ITT were standing next to their original opinion. Joel Snyder, psychologist at the University of Nevada, in Las Vegas, argued that the predictions that each team could have been generated from other theories – so experience was not a specific test of one or the other.

“It will generate confusion,” said Dr. Snyder.

In an email, Dr. Lau observed that the new study apparently did not reduce the long list of consciousness theories. “According to recent discussions, I do not have the impression that these challenges have done anything in theories,” he wrote.

But Dr. Seth has always seen a value to oppose theories to each other, even if it does not lead scientists to kill their own ideas. “The best we can expect from a successful contradictory collaboration is that other people can change their mind,” he said.