Jean-Pierre Flourens
The Greek-Roman physician Galen, in the second century, gave the name of labyrinth to the inner ear, in view of the difficulties he had in trying to understand its complicated anatomy. It reminded him of the Greek mythology story of the Cretan king Minos, who ordered the architect Dedalus to build a very complex structure where people got lost and could not find their way out. Even Dedalus, imprisoned in the labyrinth when he finished building it, could not escape.
The great anatomists gradually deciphered the enigmas of the labyrinth. The first complete description, however, had to wait for the Swedish histologist Gustav Retzius (1842-1919), who did a fantastic job of describing and drawing the inner ear, being successful in dealing with the great difficulties of tissue fixation in that time.
But even Retzius believed that the semicircular canals, the saccule and the utricle were parts of the auditory system.
Jean-Pierre-Marie Flourens was one of the first neurophysiologists, the greatest of the pioneers of the field. He founded experimental brain science, demonstrating that the mind was located in the brain and not in the heart, as it was believed in his time. He came to this conclusion by performing careful ablations of parts of the brains of animals.
His contribution to Otology was enormous; he was the first to demonstrate that the vestibular part of the inner ear was involved in balance and coordination of movements and that it was not a part of the hearing system.
Flourens was born in April 13, 1794 in Maureilhan, near Béziers. When he was 15 years old he went to Montpellier to study medicine, graduating in 1823. He then moved to Paris and began physiological research. His first publications attracted much attention, leading the Academy of Sciences of Paris to ask him to investigate the theories of Franz Joseph Gall (1758–1825), an Austrian physician that attributed different functions to different parts of the brain and that these functions caused changes in the skull. Gall’s theory had a great impact on the culture of the times and it was Napoleon – France’s emperor, at that time – who ordered the Academy of Sciences to conduct this research.
The reason for this was that Gall, who called himself a phrenologist, did not use a scientific approach, so there were many doubts about his ideas. Flourens proved that different areas of the brain indeed exerted different functions, but he also proved that Gall’s proposal that the shape of the skull was related to character was totally wrong.
In 1824 Flourens began to inflict localized lesions on the brain of rabbits and pigeons in order to observe their effects on motricity, sensitivity and behavior. He demonstrated that parts of the brain were actually responsible for definite functions. The removal of the cerebral hemispheres eliminated all perceptions; the removal of the cerebellum affected the equilibrium and motor coordination; the destruction of the brainstem caused death.
He concluded that the cerebral hemispheres were responsible for cognitive functions and that the cerebellum coordinated movements. He attributed to the brainstem the coordination of the vital functions, including respiration and blood circulation and he located the respiratory center (noeud vital) near the emergence of the vagus nerves.
Flourens made the first experimental observations on the function of the vestibular labyrinth by extirpating the semicircular canals in pigeons, one at a time. His surgical skills must have been extraordinary, since he also reported on stapedectomy in pigeons, concluding that the procedure affected their hearing.
He found that the destruction of one of the semicircular canals caused anomalous head movements in pigeons and they became unable to fly. Since their hearing was not affected, Flourens concluded that the semicircular canals were involved in the maintenance of posture and balance and were not a part of the hearing system. As stated above, he was the first scientist to describe the function of the labyrinth.
He was also a pioneer in Anesthesiology, demonstrating, in 1847, the effect of chloroform on animals.
In 1855 he became the Professor of Natural History at the Collège de France.
He died at Montgeron, near Paris on December 6, 1867. He was succeeded by another famous French neurophysiologist, Claude Bernard, who praised him eloquently but for some reason never quoted Flourens’ pioneer work on the vestibular organs.
In the city of Maureilhan, where Flourens was born, there is a plaque honoring this great scientist.
The great anatomists gradually deciphered the enigmas of the labyrinth. The first complete description, however, had to wait for the Swedish histologist Gustav Retzius (1842-1919), who did a fantastic job of describing and drawing the inner ear, being successful in dealing with the great difficulties of tissue fixation in that time.
But even Retzius believed that the semicircular canals, the saccule and the utricle were parts of the auditory system.
Jean-Pierre-Marie Flourens was one of the first neurophysiologists, the greatest of the pioneers of the field. He founded experimental brain science, demonstrating that the mind was located in the brain and not in the heart, as it was believed in his time. He came to this conclusion by performing careful ablations of parts of the brains of animals.
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| Jean-Pierre Flourens - Wikimedia Commons |
Flourens was born in April 13, 1794 in Maureilhan, near Béziers. When he was 15 years old he went to Montpellier to study medicine, graduating in 1823. He then moved to Paris and began physiological research. His first publications attracted much attention, leading the Academy of Sciences of Paris to ask him to investigate the theories of Franz Joseph Gall (1758–1825), an Austrian physician that attributed different functions to different parts of the brain and that these functions caused changes in the skull. Gall’s theory had a great impact on the culture of the times and it was Napoleon – France’s emperor, at that time – who ordered the Academy of Sciences to conduct this research.
The reason for this was that Gall, who called himself a phrenologist, did not use a scientific approach, so there were many doubts about his ideas. Flourens proved that different areas of the brain indeed exerted different functions, but he also proved that Gall’s proposal that the shape of the skull was related to character was totally wrong.
In 1824 Flourens began to inflict localized lesions on the brain of rabbits and pigeons in order to observe their effects on motricity, sensitivity and behavior. He demonstrated that parts of the brain were actually responsible for definite functions. The removal of the cerebral hemispheres eliminated all perceptions; the removal of the cerebellum affected the equilibrium and motor coordination; the destruction of the brainstem caused death.
He concluded that the cerebral hemispheres were responsible for cognitive functions and that the cerebellum coordinated movements. He attributed to the brainstem the coordination of the vital functions, including respiration and blood circulation and he located the respiratory center (noeud vital) near the emergence of the vagus nerves.
Flourens made the first experimental observations on the function of the vestibular labyrinth by extirpating the semicircular canals in pigeons, one at a time. His surgical skills must have been extraordinary, since he also reported on stapedectomy in pigeons, concluding that the procedure affected their hearing.
He found that the destruction of one of the semicircular canals caused anomalous head movements in pigeons and they became unable to fly. Since their hearing was not affected, Flourens concluded that the semicircular canals were involved in the maintenance of posture and balance and were not a part of the hearing system. As stated above, he was the first scientist to describe the function of the labyrinth.
He was also a pioneer in Anesthesiology, demonstrating, in 1847, the effect of chloroform on animals.
In 1855 he became the Professor of Natural History at the Collège de France.
He died at Montgeron, near Paris on December 6, 1867. He was succeeded by another famous French neurophysiologist, Claude Bernard, who praised him eloquently but for some reason never quoted Flourens’ pioneer work on the vestibular organs.
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| Wikimedia Commons |
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