[LUM#3] The Brain Reimagined
What if the brain wasn't what we thought it was? A true cartographer of the brain, Montpellier-based neurosurgeon Hugues Duffau discovered the incredible plasticity of our gray matter. And changed the lives of thousands of patients.
The year is 1861. French physician Paul Broca encounters a rather unusual patient: although he understands everything that is said to him, he has become unable to utter a single intelligible word. His conversations consist of a single syllable, "tan," which is how he comes to be known. Tan is aphasic, and he will forever change the history of neuroscience.
When Tan died, Paul Broca examined his brain from every angle and noticed that a small area was damaged. He concluded that this particular region controlled speech."Based on accurate observations, he drew the wrong conclusions," explains Hugues Duffau. The Montpellier-based neurosurgeon is categorical: the famous Broca's area does not exist. He cites as proof the many patients on whom he has performed total ablation of this area of the brain and who nevertheless speak without any difficulty.
Broca's error
Beyond Broca's area, it is the entire traditional conception of the brain that is questionable. "For 150 years, medicine has considered the brain to be organized into different areas controlling specific functions. Today, we know that this 'localizationist' theory is false, and yet we continue to teach it," laments the neurosurgeon, who has been on a crusade for 15 years to debunk this deeply entrenched dogma.
So how does our brain really work? "It is organized into dynamic interactive networks capable of constantly readjusting themselves. These networks differ from one person to another," replies Hugues Duffau. This "connectionist" approach explains why some patients can lead perfectly normal lives despite having a tumor the size of an orange affecting areas previously considered crucial to brain function.
"Clearly, the brain can compensate for these lesions: its incredible plasticity allows it to reorganize itself to continue functioning normally. Take the Paris metro network, for example. If you close one station, you will always find another route to get home," says the doctor. However, this is on condition that the most important connections are not affected."If you close Chatelet and Montparnasse, then you risk paralyzing traffic," warns the winner of the Herbert-Olivecrona Medal, the equivalent of the Nobel Prize in neurosurgery.
Wakeful operations
This connectionist approach has revolutionized the treatment of patients with brain tumors."As long as the tumor has not caused any disability, it can be largely removed and the patient treated without systematically resorting to chemotherapy," explains Hugues Duffau. But if every brain is different, how can we know where the Chatelet station is located in the patient's brain? There is only one solution: keep the patient awake throughout the operation. This is an unusual procedure, to say the least, but one that"allows us to check the impact of surgical procedures in real time," says Hugues Duffau.
In the operating room, "transient virtual lesions" are created in the brain using small electrical impulses emitted to very specific areas. Meanwhile, a neuropsychologist and a speech therapist ask the patient to respond to instructions in order to test their ability to speak, move, or recognize emotions. If they give the wrong answer, the doctor knows where not to operate, lest they disconnect an important network."For example, if the patient says 'un voiture' instead of 'une voiture,' I mark the area with a small label to remind myself not to remove anything from this crucial location."Does it hurt? Not at all:"The brain has no pain receptors," reassures the neurosurgeon.
Preserving quality of life
In 20 years, Hugues Duffau has operated on more than 650 patients, doubling or tripling their life expectancy. He receives dozens of men and women from all over the world suffering from brain tumors that his colleagues have deemed inoperable for fear of serious complications. "By operating on patients who are awake, we can remove as much of the tumor as possible while significantly reducing the risk of complications, which has fallen from 20% to less than 0.5%. Our priority is to preserve our patients' quality of life, which is essential." The first patients operated on in this way by Hugues Duffau were treated 20 years ago. They are still here to testify to the success of the procedure.
For early detection
2,500 to 3,000. That is the number of new patients diagnosed with glioma each year in France. " Often too late! " laments Hugues Duffau. By offering routine MRI screening, we could detect these tumors very early on and remove at least most of them," suggests the man who revolutionized neuroscience. It's an idea that is beginning to gain traction in the medical community.
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