Paul Broca had just attended a lecture at the Société d’Anthropologie de
Paris, where Ernest Aubertin had presented the case of Monsieur Cullerier,
a patient who attempted suicide by shooting himself in the forehead.
Tragically, the bullet smashed open the front of the victim’s skull,
exposing the brain, but remarkably, did not kill the patient. Admitted to
the Saint-Louis Hospital, Cullerier was conversant for the last few hours
of his life. Aubertin seized upon the opportunity to examine the patient
and to perform an outlandish experiment. He later wrote, “... curious to
know what effect it would have on speech if the brain were compressed,
we applied to the exposed part a large spatula, pressing from above
downward and a little from front to back. With moderate pressure speech
seemed to die on his lips; pressing harder and more sharply, speech not
only failed but a few words were cut off suddenly.”^5 Aubertin argued
before his Parisian colleagues that brain functionality was local; Paul
Broca pondered if the facility for speech was indeed housed near the front
of the cerebrum.
A week later, Louis Victor Leborgne (Tan) died, and an autopsy was
performed, including a dissection of his brain. An isolated syphilitic lesion
in the frontal lobe, near the lateral sulcus (the large fissure between the
frontal and temporal lobes), was found, and Broca surmised that this must
be the location where speech is generated.
He was right. For the first time in human history, a scientist had
identified a specific region of function in the human brain. Even today,
this region is still called “Broca’s area.” The curious doctor from Paris set
the stage for cognitive neuroscience and jump-started the true
understanding of localization and lateralization of brain function.
Wilhelm Röntgen discovered X-rays in 1895, heralding mankind’s
original capacity to peer inside a live person’s body. But X-rays are
completely incapable of revealing internal damage to the brain. While
pneumoencephalography was invented in 1919 by Johns Hopkins’s Walter
Dandy (wherein air was pumped into the hollow chambers deep inside the
brain and follow-up X-rays of the cranium revealed a ghostlike silhouette
of the brain), it wasn’t until the 1970s that CT scans and MRI scans could
painlessly and accurately show the internal structures of the cranial vault.
Therefore, from the 1860s until the 1960s, the process of determining the
functional areas of the human brain was entirely based upon postmortem
examination of a brain-injured patient. To truly unlock the secrets of the