Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS

NOVA Online (see text links below)
Secrets of the Mind  
Brain-Mapping Pioneers

What would you do if you were a doctor and had patients who were missing pieces of their skulls? If you were Eduard Hitzig, a German doctor working at a military hospital in the 1860s, you'd conduct some experiments. Hitzig, working on patients who had pieces of their skulls blown away in battle, stimulated exposed brains with wires connected to a battery. By doing so, he discovered that weak electric shocks, when applied to areas at the back of the brain, caused the patients' eyes to move.


Wilder Penfield Wilder Penfield, a pioneering brain surgeon, mapped the motor cortex using mild electric current.
Later, around 1870, Hitzig teamed up with another doctor, Gustav Fritsch. Setting up a makeshift lab in Fritsch's house, the two stimulated the brains of live dogs. They found that not only could they cause crude movements of the dogs' bodies, but that specific areas of the brain controlled specific movements.

John Hughlings Jackson, an English scientist, soon after took the work of Fritsch and Hitzig even further. Based on his observations of his wife's epileptic seizures, Jackson came up with a more detailed theory of how the brain controls muscles. He knew that every one of her seizures followed the same pattern: It would start at one of her hands, move to her wrist, then her shoulder, then her face. It would finally affect the leg on the same side of her body, then stop.

Jackson believed that the seizures were electrical discharges within the brain. The discharges started at one point and radiated out from that point. This suggested that the brain was divided into different sections, and that each section controlled the motor function (or movement) of a different part of the body. And since the pattern never varied, the way the brain is organized must also be set.

Exposed cortex A brain exposed during surgery.

Wilder Penfield took the next exploratory voyage into the brain starting in the 1940s. While operating on epileptic patients, Penfield applied electric currents to the surface of patients' brains in order to find problem areas. Since the patients were awake during the operations, they could tell Penfield what they were experiencing. Probing some areas triggered whole memory sequences. For one patient, Penfield triggered a familiar song that sounded so clear, the patient thought it was being played in the operating room.

During these operations, Penfield watched for any movement of the patients' bodies. From this information, he was able to map the motor cortex, the very part of the brain you can map in this feature's activity.

Probe the Brain | A Map of the Motor Cortex



Photos: (1) Princeton University Press; (2) Courtesy of John Postlethwait.

Printer-Friendly Format   Feedback
Visual Mind Games | From Ramachandran's Notebook | The Electric Brain | Probe the Brain
Resources | Teacher's Guide | Transcript | Site Map | Secrets of the Mind Home

Search | Site Map | Previously Featured | Schedule | Feedback | Teachers | Shop
Join Us/E-Mail | About NOVA | Editor's Picks | Watch NOVAs online | To print
PBS Online | NOVA Online | WGBH

© | Updated October 2001
 

Support provided by

For new content
visit the redesigned
NOVA site

Shop Teachers Feedback Schedule Previously Featured Site Map Search NOVA Home Secrets of the Mind Home Site Map