7474 BBC SCIENCE FOCUS BBC SCIENCE FOCUS MAGAZINE COLLECTIONMAGAZINE COLLECTION
THE FUNDAMENTALS OF LIFE
SCIENCEPHOTO^ LIBRARY,^ GREG^ DUNNChristopher Wren’s highly detailed illustrations
complemented Thomas Willis’s writings about
the brain’s anatomyTHE HISTORY OF
BRAIN RESEARCH
Doctors and neuroscientists have been attempting to unravel the
secrets of the brain for centuries – but it has proved a tough nut
to crack. Dr Christian Jarrett charts the major discoveries
R
ome, 2nd century AD. An
audience of philosophers a nd
politicians has gathered to watch
Galen of Pergamon, the ‘prince of
physicians’, perform a public
demonstration involving a pig. The
animal’s squealing falls suddenly
silent as Galen severs its laryngeal
nerve – the neural link connecting
its voice box to its brain. The crowd
audibly gasps with astonishment.
Why were they so shocked? Galen
had just proved that the brain, not
the heart, controls behaviour.
This might not sound ground-
breaking to our modern ears, but the
historian Charles Gross describes
it as “one of t he most fa mous single
physiological demonstrations of all
time.” Although Galen wasn’t the first
to recognise the brain’s functional
importance, he was the first to carry
out a public experiment supporting
his case. In Galen’s time, the
‘cardiocentric view’ – the idea that
thought, mind and soul are located in
the heart – remained dominant and
would do so for centuries. Its legacy
lives on today with sayings such as
“learn things by heart”.
The pig demonstration reflects the
longer story of how we’ve come to
understand the brain – it’s a tale of
colourful characters, ghoulish
experiments and stubborn myths.Throughout much of history, our
understanding of the brain was often
more of a philosophical than a
scientif ic pu rsuit. This is pa r tly
because, until the last century, the
biological study of our grey matter
was mostly dependent on post-mortem
investigations of animal brains and
bodies, and only more rarely – thanks
to a long-running church ban – human
brains. It’s amazing to think that as
late as 1652, the philosopher Henry
More wrote that the brain had no morecapacity for thought than “a cake of
suet or a bowl of cu rds”.
One of the most influential brain
dissectors who helped over tu r n t hese
beliefs was the English doctor Thomas
Willis. He authored the magisterial
book Anatomy of the Brain, published
in 1664. Willis made astute and
visionary arguments that complex
mental functions are carried out by
the cerebral cortex. This part of the
brain had long been seen as little more
than a useless ‘rind’ – cortex means
‘rind’ or ‘husk’ in Latin.
The continuing lack of scientific
knowledge about the brain allowed
mistaken theories to survive until
quite recently, theories that seem
absu rd by moder n sta nda rds. For
example, another long-running belief
(this one strongly endorsed by Galen)
was that the brain pumps ‘animal
spirits’ around the body. Physicians
and scientists believed right up until
the 18th century that nerves were
filled with these animal spirits –
bizarre entities that the philosopher
René Descartes described as “a very
f ine wind”. The brea kt h rough t hat led
to t his idea being over tu r ned had to do
with electricity and specifically the
emergence of electrotherapy as a
treatment for paralysis.
Public demonstrations again played
their part in changing minds. In an 5