The more that I looked at DNA, the more I realized it was nature and nurture. It's how genes and your environment work together to produce the person you are.
Over the years, humans have managed to incorporate nearly every element, light and weighty, common and obscure, into our daily lives. And given how small atoms are and how many of them there are all around us, it's almost certain that your body has at least brushed against an atom of every single natural element on the periodic table.
Atoms consist of a positive nucleus and negative electrons flying around outside it. Electrons closest to the nucleus feel a strong negative-on-positive tug, and the bigger atoms get, the bigger the tug. In really big atoms, electrons whip around at speeds close to the speed of light.
Without a functioning hippocampus, names, dates, and other information falls straight through the mind like a sieve.
Brain surgery couldn't happen without the patient's own active voice to guide the work. The patient is part of the surgical team here, perhaps the most important part, and above all, that's what makes neurosurgery different.
If studying the periodic table taught me nothing else, it's that the credulity of human beings for periodic table panaceas is pretty much boundless.
Something funny certainly happens when palladium and platinum come into contact with hydrogen gas; it's one of the great mysteries still waiting to be solved on the periodic table. But it's quite a leap from 'something funny' to cold fusion.
Before the Human Genome Project, most scientists assumed, based on our complex brains and behaviors, that humans must have around 100,000 genes; some estimates went as high as 150,000.
In a vague way, I always knew neurosurgery was different - more delicate, more difficult, more demanding. After all, we say things like, 'I'm no brain surgeon,' for a reason.
In some sense, what you might have suspected from the first day of high-school chemistry is true: The periodic table is a colossal waste of time. Nine out of every 10 atoms in the universe are hydrogen, the first element and the major constituent of stars. The other 10 percent of all atoms are helium.
Guinea pigs are practically synonymous with experiments. Lab rats have become the workhorses of modern medicine. Genetics owes a huge debt to the humble fruit fly. There's almost no branch of the life sciences, in fact, that hasn't leaned heavily on one animal or another.
The amygdala is indeed crucial for monitoring our environment and deciding what's worth getting worked up over. Once the amygdala determines this, however, it merely trips another circuit to actually produce the panic.
Atoms of Element 118 fill an outer shell with electrons, creating a special type of element called a noble gas. Noble gases are natural turning points on the table, ending one row and pointing to the next.
Some scientists claim - although these claims are contentious - that they can form deadly isomers with simple X-rays and that hafnium can multiply the power of these X-rays to an astounding degree, converting them into gamma rays up to 250 times more potent than the X-rays.
Despite the disreputable company it keeps, bismuth is harmless. In fact, it's medicinal: Doctors prescribe it to soothe ulcers, and it's the 'bis' in hot-pink Pepto-Bismol. Overall, it seems like the most out-of-place element on the periodic table, a gentleman among scoundrels.
Except for certain moments - when cells are dividing, for instance - chromosomes don't form compact, countable bodies inside cells. Instead, they unravel and flop about, which makes counting chromosomes a bit like counting strands of ramen in a bowl.
America was probably Europe's equal scientifically by the end of World War I and certainly surpassed it after the chaos of World War II.
Most people, even most doctors, learn that the placenta is a nice, tight seal that prevents anything in the mother's body from invading the fetus, and vice-versa. That's mostly true. But the placenta doesn't seal off the baby perfectly, and every so often, something slips across.
Your body thinks radium is a great thing to pack into bone - where it kills some cells outright and scrambles the DNA of others, causing problems like cancer.
We know that genes shape human cultures and human societies: The DNA we inherited from our ancestors makes certain foods taste better, affects the way we care for children, influences what colors we find vibrant, and contributes to our love of socializing, among other examples.
No one knows quite the reason, but surgically severing the corpus callosum can reduce the rate and intensity of seizures. So in the early 1960s, a few patients with severe epilepsy had their corpus callosums cut, turning them into split-brain people.
There are a few elements - especially platinum and palladium - that have the amazing ability to absorb up to 900 times their own volume in hydrogen gas. To get a sense of the scale there, that's roughly equivalent to a 250-pound man swallowing something the size of a dozen African bull elephants and not gaining an inch on his waistline.
Unlike uranium, plutonium was created in an American lab in 1940, but scientists soon realized that it could produce even wilder chain reactions and even bigger explosions. In fact, fearing another country would create it, too, the American government went to great lengths to keep even the existence of plutonium a secret.
We human beings are humane in part because we can look beyond our biology.
One theme I ran into over and over while writing about the periodic table was the future of energy and the question of which element or elements will replace carbon as king.
Among physicists and chemists, cold fusion - nuclear fusion at close to room temperature - enjoys a reputation about on par with creationism.
The hippocampus helps record both types of memories initially, and it helps retain them for the medium term. The hippocampus also helps us access old personal memories in long-term storage in other parts of the brain.
Scientists didn't discover the noble gas helium - the second most common element in the universe - on Earth until 1895. And they thought it existed in minute quantities only, until miners found a huge underground cache in Kansas in 1903.
It's often meaningless to talk about a genetic trait without also discussing the environment in which that trait appears. Sometimes, genes don't work at all until the environment awakens them.
Genes are like the story, and DNA is the language that the story is written in.
Even if we never cure a single disease, the Human Genome Project and other ventures will have been worth it.
I think it's a natural human tendency, when you read something, you tend to read a lot of your prejudices into it. And neuroscience is like a lot of disciplines - it has fashions; things change.
Despite its obscurity, probably no element on the periodic table has as colorful a history as antimony. Money, madness, poison, linguistics, charlatanism, sex - pretty much every theme that runs through the periodic table can be found in Element 51.
Most people who have encountered mercury have done so after breaking a mercury thermometer. And many of us who saw the liquid balls of mercury scatter across a floor or countertop considered the element the most beautiful on the periodic table.
Despite what you might guess, when monitoring your breathing, your body doesn't care whether you're inhaling enough oxygen. It cares only whether you're expelling enough carbon dioxide - that's the gas that sets off the panic button when you're suffocating.
Aluminum is the most common metal in the earth's crust, almost twice as abundant as iron. And one common class of aluminum minerals, collectively called alum, has been in use since at least Greek and Roman times.
The inability to trace DNA to actual diseases has serious consequences. As does the opposite problem - not being able to trace diseases back to DNA.
Even fictional characters sometimes receive unwarranted medical opinions. Doctors have diagnosed Ebenezer Scrooge with OCD, Sherlock Holmes with autism, and Darth Vader with borderline personality disorder.
Most organisms have loads of junk DNA - less pejoratively, noncoding DNA - cluttering their cells.
While our amplified knowledge of genetics - and the increasing precision of the field - does make it tempting to take on celebrity cases, retro-genetics can't always provide clear answers.
People adored Element 13's color and luster, which reminded them of the sparkle of gold and silver - a brand-new precious metal. In fact, aluminum became more precious than gold and silver in the 19th century because it was harder to obtain.
To be sure, ASPM isn't the gene responsible for building big brains - there's no such single gene. But it's critical to the process, and the primate line has almost certainly benefited from distinct changes in ASPM.
On a submicro scale, pure diamond is billions of billions of carbon atoms bonded to one another. If you shrunk yourself down and stood inside the diamond, you'd see nothing but carbon in a perfect pattern in every direction.
The brain, which is plastic when young, must be exposed to certain sights early in life, or it will remain blind to those sights forever.
The noble gases, which reside on the East Coast of the periodic table, are its aristocrats - detached and aloof, never bothering to interact with the rabble of common elements that make up the vast majority of the world.
Although it's the hub of the nervous system and the ultimate terminus of every nerve, the brain itself lacks enervation and therefore cannot feel pain.
The humped bladderwort has yellow, snapdragon-like flowers, and it's actually carnivorous, capable of trapping and eating not just insects but even tadpoles and tiny fish.
Radium, discovered by Marie and Pierre Curie in 1898, was especially popular: the 'it' element of its day. Radium glows an eerie blue-green in the dark, giving off light for years without any apparent power source. People had never seen anything like it.