TITLE:
Louis Pierre Gratiolet (1815-1865) and His Contribution to the Study of Cerebral Convolutions in Primates
AUTHORS:
André Parent
KEYWORDS:
Humans; Primates; Cerebral Hemispheres; Cerebral Convolutions; Cerebral Cortex; Neuroscience History
JOURNAL NAME:
Neuroscience and Medicine,
Vol.5 No.1,
March
6,
2014
ABSTRACT: Louis Pierre Gratiolet (1815-1865) was one of the
first modern anatomists to pay attention to cerebral convolutions. Born in
Sainte-Foy-la-Grande (Gironde), he moved to Paris in 1834 to study medicine, as
well as comparative anatomy under Henri de Blainville (1777-1850). In 1842, he
accepted de Blainville’s offer to become his assistant at the Muséum d’histoire naturelle and progressively
abandoned medicine for comparative anatomy. He undertook a detailed study of
brains of human and nonhuman primates and soon realized that the organizational
pattern of cerebral convolutions was so predictable that it could serve as a
criterion to classify primate groups. He noted that only the deepest sulci
exist in lower primate forms, while the complexity of cortical folding
increases markedly in great apes and humans. Gratiolet provided the first
cogent description of the lobular organization of primate cerebral hemispheres.
He saw the insula as a central lobe around which revolved the frontal,
parietal, temporal (temporo-sphenoidal) and occipital lobes. He correctly
identified most gyri and sulci on all brain surfaces, introduced the term “plis de passage” for some interconnecting
gyri, and provided the first description of the optic radiations. In the early
1860s, Gratiolet fought a highly publicized battle
against Paul Broca (1824-1880) on the relationship between brain and intelligence. Gratiolet agreed that the
brain was most likely the seat of intelligence, but he considered human
cognition far too subtle to have any direct relationship with brain size. He argued that a detailed study of the human brain architecture would be more profitable than Broca’s vain speculations on
the relationship between brain weight and intelligence, which he considered a
monolithic entity. Despite remarkable scientific achievements and a unique
teaching capacity, Gratiolet was unable to secure any academic position until
three years before his sudden death in Paris at age 49.