Surprising study results show that with a little stimulation, a previously unremarkable part of the brain actually causes a feeding frenzy in mice. The are linking the findings with a strange symptom that comes from a similar circumstance related to Parkinson’s Disease. When electrodes are implanted into human brains to ease their symptoms, they develop an incredible hunger.
Nerve cells in a poorly understood part of the brain have the power to prompt voracious eating in already well-fed mice.
Two to three seconds after blue light activated cells in the zona incerta, a patch of neurons just underneath the thalamus and above the hypothalamus, mice dropped everything and began shoveling food into their mouths. This dramatic response, described May 26 in Science, suggests a role in eating behavior for a part of the brain that hasn’t received much scrutiny.
Scientists have previously proposed a range of jobs for the zona incerta, linking it to attention, movement and even posture. The new study suggests another job — controlling eating behavior, perhaps even in humans. “Being able to include the zona incerta in models of feeding is going to help us understand it better,” says study coauthor Anthony van den Pol, a neuroscientist at Yale University.
The new results may also help explain why a small number of Parkinson’s disease patients develop binge-eating behavior when electrodes are implanted in their brains to ease their symptoms. Those electrodes may be stimulating zona incerta nerve cells, van den Pol suspects.
During intermittent stimulation of some zona incerta…
Whether or not we act out a predetermined role in life or set our own course, has been argued for time immemorial, by philosophers, scholars, and theologians alike. Traditionally, there was an East-West dichotomy. In Eastern philosophies, generally speaking, one was the subject of fate.
People did best in this view, when they recognized their role in the universe and took part in it, wholeheartedly. In the West, humans were thought, by and large, to be imbued with free will. This comes from ancient Greece as much as the Judeo-Christian tradition. Still, free will vs. fate has been debated in the West for ages.
So which is our actual nature? Do we have free will or is it all just an illusion? With the benefits of modern science, we’re able to probe this ancient quandary in new and exciting ways. Today, neuroscientists, psychologists, and physicists have each approached the question in a different way.
Jerry Coyne is an evolutionary biologist at the University of Chicago. He says that all of our choices are determined by molecules in the brain, genes, and the environment. Sam Harris goes a step farther. He’s a philosopher and neuroscientist. Harris wrote a book about how the latest in neuroscience unravels the case for free will irreparably.
According to that field, we make decisions even before we’re consciously aware of them. Decades worth of experiments offer evidence, starting in the 1980s with EEG machines and more recently, with fMRIs and even implants, which read neurons directly inside the brain.
In 1999, psychologists Dan Wegner and Thalia Wheatley conducted a series of experiments to see how the brain made decisions. They found that there is a quarter-of-a-second lag between the time we make a choice and when our conscious mind becomes aware of it.
Brain scan studies have shown that we make decisions even before we’re consciously aware of them. Getty Images.
The implications are vast. If we could map a person’s brain in its entirety and know their complete genetic makeup, we’d be able to predict with 100% accuracy, in theory, their response to any given situation. Though American society is based on the idea of free will, such as meritocracy and the American dream, these findings from neuroscience are starting to leak into court rooms and other institutions.
“I wish you could know what it means to be me,” Nina Simone sang in her 1967 civil rights anthem “I Wish I Knew How It Would Feel To Be Free” — an invitation to empathy at the heart of which is the animating question of consciousness: What does the experience of being feel like from the inside and can that subjective experience ever be fully understood from the outside?
“Everything begins with consciousness and nothing is worth anything except through it,” 28-year-old Albert Camus proclaimed in his meditation on the nature of consciousness just as modern science was beginning to wrest the question from the reposable thumbs of philosophers. Well before Santiago Ramón y Cajal fathered modern neuroscience and set it loose on addressing these questions over the course of the following century, the poet Emily Dickinson captured this elemental paradox of existence in a verse that remains the ultimate ode to — or is it a lamentation of? — consciousness:
How have I peace
Except by subjugating
And since We’re mutual Monarch
How this be
Except by Abdication —
Me — of Me?
Koch describes himself as a “romantic reductionist” — a reductionist because he seeks “quantitative explanations for consciousness in the ceaseless and ever-varied activity of billions of tiny nerve cells, each with their tens of thousands of synapses,” and romantic on account of his conviction that “the universe has contrails of meaning that can be deciphered in the sky above us and deep within us” — meaning illuminated not within the blink of an individual existence but across the vast cosmic scales of space and time. (Physicist Sean Carroll would later call such an orientation to the quest for meaning “poetic naturalism.”)
Two millennia after Plato’s famous allegory of the cave, Koch writes with an eye to the central inquiry of his life’s work:
Without consciousness there is nothing. The only way you experience your body and the world of mountains and people, trees and dogs, stars and music is through your subjective experiences, thoughts, and memories. You act and move, see and hear, love and hate, remember the past and imagine the future. But ultimately, you only encounter the world in all of its manifestations via consciousness. And when consciousness ceases, this world ceases as well.
Consciousness is the central fact of your life.
In addition to the paradox consciousness presents to the experiencing self, Koch points out that it presents a second paradox to science — on the one hand, it challenges the scientific model of the world by raising the same questions that mystics have been asking for millennia; on the other, it lends itself to being investigated empirically with the very tools of the scientific method and, as Koch puts it, “with both feet firmly planted on the ground.”
Having devoted much of his life to uncovering “how a highly organized piece of matter can possess an interior perspective,” Koch considers one of the most interesting questions of consciousness — that of qualia, the subjective interiority of experiences. (Nina Simone’s moving lyric line brings into sharp relief the grandest quale of all — that of selfhood.) Koch writes:
What it feels like to have a particular experience is the quale of that experience: The quale of the color red is what is common to such disparate percepts as seeing a red sunset, the red flag of China, arterial blood, a ruby gemstone, and Homer’s wine-dark sea. The common denominator of all these subjective states is “redness.” Qualia are the raw feelings, the elements that make up any one conscious experience.
Some qualia are elemental — the color yellow, the abrupt and overpowering pain of a muscle spam in the lower back, or the feeling of familiarity in déjà vu. Others are composites — the smell and feel of my dogs snuggling up against me, the “Aha!” of sudden understanding, or the distinct memory of being utterly transfixed when I first heard the immortal lines: “I’ve seen things you people wouldn’t believe. Attack ships on fire off the shoulder of Orion. I’ve watched c-beams glitter in the dark near the Tannhäuser Gate. All those…
The African naked mole rat (Heterocephalus glaber) is repulsive. It looks like an octogenarian sausage with buck teeth. Mostly found in the horn of Africa, these rodents live in warrens underground, serve a ruling queen, and spend most of their days gathering seeds and edible plants, or digging elaborate tunnels with their protruding front teeth and snouts. They live dozens and sometimes hundreds together and only the queen mates and bears young. In this way, they operate more like ants or bees than mammals.
Turns out these heinous, hairless monstrosities are a scientific marvel in quite a number of ways. For instance, they’re cold-blooded. These mole rats survive much, much longer than any other rodent, around 30 years or so. The naked mole rat doesn’t experience most kinds of pain and might even help us cure cancer. They don’t develop it. When researchers tried to sow cancer within them, they proved resistant.
Perhaps the most extraordinary thing about them is, they can survive for a long time without oxygen. Now, researchers have found out why. Turns out, they borrow a biochemical process from plants, according to a recent study published in the journal Science. Neuroscientist Thomas Park, a researcher from the University of Illinois-Chicago, told NPR that he and colleagues wanted to know how long the naked mole rat could last without oxygen.
How naked mole rats survive in low oxygen environments has been a mystery, until now. By Bernard DuPont from France [CC BY-SA 2.0], via Wikimedia Commons
First they stuck four mole rats in a chamber which mimicked a low oxygen environment, one that would kill a mouse in about 15 minutes. Subjects became sluggish but were unfazed otherwise. They were in there for five hours without any trouble. This aspect of their physiology is important for their survival, as in the wild, they spend long period in tunnels where very little oxygen can be had….