Name: 【TED-Ed】The great brain debate - Ted Altschuler
Uploaded: 2014-12-29T19:05:36.000Z
Duration: 5 min 20 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Adverbs of degree

In 1861, two scientists got into a very brainy argument.

Adverbs of manner

Specifically, they had opposing ideas of how speech and memory

Earnest Aubertin,  with his localistic model,

argued that a particular region or the brain

Pierre Gratiolet, on the other hand, argued for the distributed model,

to accomplish all of these  various functions.

The debate they began reverberated throughout the rest of the century,

involving some of the greatest scientific minds of the time.

Aubertin and his localistic model had some big names on his side.

In the 17th century, René Descartes had assigned the quality

of free will and the human soul to the pineal gland.

And in the late 18th century, a young student named Frans Joseph Gall

had observed that the best memorizers in his class had the most prominent eyes

and decided that this was due  to higher development

As a physician, Gall went on to establish the study of phrenology,

which held that strong mental faculties corresponded to

highly developed brain regions, observable as bumps in the skull.

The widespread popularity of phrenology throughout the early 19th century

tipped the scales towards  Aubertin's localism.

But the problem was that Gall had never bothered to scientifically test

whether the individual brain maps he had constructed

And in the 1840's, Pierre Flourens challenged phrenology

by selectively destroying parts of animal brains

interfered with judgement or movement in general,

but failed to identify any region associated with one specific function,

concluding that the cortex carried out brain functions as an entire unit.

Flourens had scored a victory  for Gratiolet, but it was not to last.

Gall's former student,  Jean-Baptiste Bouillaud,

observing that patients  with speech disorders

And after Paul Broca's 1861 autopsy of a patient who had lost the power

to produce speech, but not the power to understand it,

revealed highly localized  frontal lobe damage,

In the 1870's, Karl Wernicke associated part of the left temporal lobe

Soon after, Eduard Hitzig and  Gustav Fritsch

stimulated a dog's cortex and discovered a frontal lobe region

Building on their work, David Ferrier mapped each piece of cortex

associated with moving a part of the body.

And in 1909, Korbinian Brodmann built his own cortex map with 52 separate areas.

It appeared that the victory of Aubertin's localistic model was sealed.

But neurologist Karl Wernicke had come up with an interesting idea.

He reasoned that since the regions for speech production and comprehension

then injuring the area  connecting them might result

in a special type of language loss, now known as receptive aphasia.

Wernicke's connectionist model helped explain disorders

that didn't result from the dysfunction  of just one area.

Modern neuroscience tools reveal a brain more complex than

Gratiolet, Aubertin, or even Wernicke imagined.

Today, the hippocampus is associated with two distinct brain functions:

creating memories and processing location in space.

We also now measure  two kinds of connectivity:

anatomical connectivity between  two adjoining

and functional connectivity  between separated regions

working together to accomplish one process.

is actually composed  of many smaller functions,

with different parts  of the cortex representing

When certain areas stop functioning, we may recognize an object,

There are even different kinds of memory for facts and for routines.

And remembering something  like your first bicycle

involves a network of different regions each representing the concept

of vehicles, the bicycle's shape,  the sound of the bell,

and the emotions associated  with that memory.

In the end, both Gratiolet and Aubertin turned out to be right.

And we still use both of their models to understand how cognition happens.

For example, we can now measure brain activity on such a fine time scale

that we can see the individual localized processes that comprise

But it is the integration of these different processes and regions

that creates the coherent memory we experience.

The supposedly competing theories prove to be two aspects

which will in turn be revised and refined

as our scientific techologies and methods for understanding the brain improve.