| Monday, February 12, 2007
| LET'S TALK ABOUT THE BRAIN
|FIVE PATHS TO UNDERSTANDING
From gruesome ancient rituals to modern pharmacology, manking has been trying to discover what's really going on inside our heads. A short history.
Ancient Beliefs What is the brain?
Earlt evidence of trephination, a primitive brain surgery in which a hole is cut through the skull. The practice, which persisted through the Middle Ages, was sometimes used to treat seizures or headaches.
The first known writing about the brain describes the mind-altering sensations that result from eating poppies.
Hippocates describes epilepsy as a disorder of the brain, not a curse from the Gods. He also believes the brain is the seat of intelligence and emotion.
387 - 335 B.C.
Plato believes the brain controls intelligence and is "the divinest part of us". Aristotle, his student, believes the brain merely cools hot blood from the heart.
Galen, physician to Roman gladiators, dissected the brains of sheep, monkeys, dogs and swine. He concludes that the cerebellum controls the muscles while the cerebrum processes the senses.
Anatomy How is the brain built?
The 15 ft.-long Edwin Smith Surgical Papyrus, a copy of Egyptian records from 3000 B.C., includes the earliest account of the anatomy of the brain and describes 27 cases of brain injury.
Alexandrian biologists Herophilus, the "father of anatomy", and Erasistraus, his student, are the first to rely on dissection of the human body to study the brain and describe the nervous system.
1100 - 1500
Quack practiced in sleight of hand go across Europe, claiming they can cure mental ilnesses by removing "stones from madness" from the brain.
Thomas Willis, an Oxford professor, writes Cerebri Anatome, the most detailed description yet of the nervous system. Willis believes separate parts of the brain are responsible for thoguht and movement.
Franz Joseph Gall, a German anatomist, creates phrenology, a pseudosciense based on the idea that a person's personality is rvealed by the contours of the head.
Railroad worker Phineas Gage's skull is pierced by an iron rod. He lieve, but his personality reportedly changes, raising questions about how the brain's frontal regions affect behaviour.
Psychology How does the mind work?
Rene Descartes tackles the philosophical distinction between mind and body by proposing that the immaterial soul enters he body through the brain's pineal gl;and.
A decade after his cousin Charles Darwin published The Origin of Species, Francis Galton writes Hereditary Genius, in which he postulates that intelligence is inherited.
William James publishes Principles of Psychology, a monumental work widely hailed for its rich and insightful descriptions of human nature and behavior.
Sigmund Freud argue in Interpretation of Dreams that dreams are windows to an otherwise inacceible mind, "the royal road to the unconcious". It takes eight years to sell 600 copies.
In a famous expriment with dogs and dinner bells, Ivan Pavlov explores conditoned responses, an animal's involuntary reaction to stimuli, such as drooling at the sound of a bell.
B.F. Skinner describes how an animal's behaviour can be engineered through positive and negative reinforcement.
Disorders Can we fix the brain?
St. Mary of Bethlehem is England's first hospital for the mentally ill, and a variant of its name, bedlam, comes to signify all psychiatric facilities.
Jojann Jakof Wepfer proposes that stroke is caused by a broken blood vessel in the frain.
Emil Kraepelin describes schizophrenia and manic depression.
Alois Alzheimer details presenile degeneration, which in 1910 becomes known as Alzheimer's disease.
Egas Moniz publishes a description of human frontal lobotomy as a treatment for psychosis.
Australian Jphn Cade publishes findings that lithium is an effective treatment for bipolar disorder.
Prozac is approved by the Food and Druv Administration as a treatment for depression.
Neuroscience What powers the brain?
Studying frogs, Luigi Galvani, an Italian physiologist, is the first to propose that some form of "animal electricity" secreted by the brain drives nerve activity.
Camillo Golgi develops a staining method that reveals the detailed structure of sensory nerve cells that feed into the brain.
Henry Hallett Dale, and Otto Loewi share the Nobel Prize for describing acetylcholine, a major chemical transmiter of nerve impulses.
Michael Phelps, Edward Hoffman and Michael Ter Pogossian develop the positron emission tomography scanner, which uses radioactive agents to image the brain.
Fred Gage at the Salk Institute publishes a groundbreaking paper describing for the first time the ability of adult brain neurons to regenerate.
First gene=theraphy trial to treat the brain disorder Alzheimer's disease.
(Source:TIMEMAG: A User's Guide to the Brain - Special Issue Edition)
|posted by infraternam meam @ 11:37 AM