Posts tagged ‘neuroscience’

Intelligence Is in the Genes, but Where?

You can thank your parents for your smarts—or at least some of them. Psychologists have long known that intelligence, like most other traits, is partly genetic. But a new study led by psychological scientist Christopher Chabris of Union College reveals the surprising fact that most of the specific genes long thought to be linked to intelligence probably have no bearing on one’s IQ. And it may be some time before researchers can identify intelligence’s specific genetic roots.

Chabris and David Laibson, a Harvard economist, led an international team of researchers that analyzed a dozen genes using large data sets that included both intelligence testing and genetic data.

In nearly every case, the researchers found that intelligence could not be linked to the specific genes that were tested. The results are published online in Psychological Science, a journal of the Association for Psychological Science.

“In all of our tests we only found one gene that appeared to be associated with intelligence, and it was a very small effect. This does not mean intelligence does not have a genetic component. It means it’s a lot harder to find the particular genes, or the particular genetic variants, that influence the differences in intelligence,” said Chabris.

It’s important to remember that we aren’t flowers, that intelligence is immensely more complex than the color of petals. There isn’t an “intelligence gene,” but rather a bunch of genes that influence it both individually and in cooperation with others. In addition, we aren’t positive on how the nurture-vs-nature relationship works in either. 


The Connectome Debate: Is Mapping the Mind of a Worm Worth It?

The connectome-related skepticism has been ramping up lately. So you mapped the complete neural network of a tiny worm (C. elegans, above) … so what? So you draw some pretty brain structures that don’t provide neuron by neuron detail … so what?

Ferris Jabr has a great write-up of the “so whats” and the “this is what” at SciAm. Want to get up to date on the connectome debate? Start here.

Because a lone connectome is a snapshot of pathways through which information might flow in an incredibly dynamic organ, it cannot reveal how neurons behave in real time, nor does it account for the many mysterious ways that neurons regulate one another’s behavior. Without such maps, however, scientists cannot thoroughly understand how the brain processes information at the level of the circuit. In combination with other tools, the C. elegans connectome has in fact taught scientists a lot about the worm’s behavior; partial connectomes that researchers have established in the crustacean nervous system have been similarly helpful. Scientists are also learning how to make connectomes faster than before and to enhance the information they provide. Many researchers in the field summarize their philosophy like this: “A connectome is necessary, but not sufficient.”

So it’s taught us a bit about the workings of the worm, but maybe not everything. Will it translate to elucidating the workings of the human brain? Time will tell. Good read.

(via Scientific American)

A way to look at how certain stimulant drugs affect your central nervous system…


…using a GIF of water filling up a sink as an analogy for dopamine:

I love simple explanations.

(via @stevesilberman)


Badass Scientist of the Week: Dr. Benjamin Carson

Dr. Benjamin Carson (1951—) is an internationally acclaimed neurosurgeon, author, public speaker and surgical pioneer. He came from humble origins, raised in Detroit by a single mother, Sonya, who worked several jobs to keep her family afloat. Sonya had dropped out of school in third grade, but she was dedicated to helping her two young sons become successful—thanks to her, the unwilling Carson became a voracious reader and rose from the bottom to the top of his class. He attended Yale on a scholarship, where he completed a degree in Psychology, but in medical school his interests switched from psychiatry to neurosurgery—his ability to visualize the brain in three dimensions and his excellent hand-eye coordination made him an ideal surgeon. He soon became the first African American accepted into the residency program at the prestigious Johns Hopkins Hospital. After a time in Perth, Australia, as chief neurosurgical resident at the Sir Charles Gairdner Hospital, Carson returned to the US and was named director of pediatric neurosurgery at Johns Hopkins—the youngest doctor ever to receive the honour, at age 33. He still holds this position today. He quickly became renowned as a skilful surgeon who would take on risky or hopeless cases, combining surgical skills and knowledge with new technology. Carson is particularly well known for his work on conjoined twins, and he made medical history in 1987 by separating a pair of Siamese twins joined at the back of the head. He’s also revived a procedure called a hemispherectomy to treat patients who suffer from chronic seizures, developed a method to treat brain-stem tumours, was the first doctor to operate on a fetus in the womb, and has received the Presidential Medal of Freedom. Carson currently operates on 300 children a year, and is in high demand as a public speaker—he’s dedicated to helping young people realise than anything is possible, no matter who you are.

To reflect the ongoing structural changes in the adolescent and twenty-something brain, many journalists and scientists use words and phrases like “unfinished,” “work in progress,” “under construction” and “half-baked.” Such language implies that the brain eventually reaches a kind of ideal state when it is “done.” But there is no final, optimal state. The human brain is not a soufflé that gradually expands over time and finally finishes baking at age 30. Yes, we can identify and label periods of dramatic development—or windows of heightened plasticity—but that should not eclipse the fact that brain changes throughout life.


Whether we can, at this moment in time, meaningfully link this life stage to neuroscience seems a tenuous proposition at best. By itself, brain biology does not dictate who we are. The members of any one age group are not reducible to a few distinguishing structural changes in the brain. Ultimately, the fact that a twenty-something has weaker bridges between various brain regions than someone in their thirties is not hugely important—it’s just one aspect of a far more complex identity.

The Neuroscience of 20-Somethings by Scientific American’s Ferris Jabr (via explore-blog)

As with most things related to the human condition, it is nearly impossible to describe it with one or two words. The brain, an incredibly complex organic computer, can certainly not be summed up by “half baked” at any stage.


All vertebrates’ eyes emerge from a single group of cells, called the eye field, located in the middle of the brain. The eye field cells evaginate to form two optic vesicles, which eventually give rise to two retinas, one on either side of the brain.

Eyes Emerge

Top image: In a ~5 somites embryo, eye field cells are stained red, and forebrain cells are outlined in green (upper left). A few hours later, in a ~10 somites embryo, the eye field (green) separates into two optic vesicles. At the same embryonic stage, the dorsal telencephalon, which sits atop the evaginating eyes, is labeled blue (bottom left). In both of these images, a midline positioned cross outlines the apical surface of the optic vesicles and the ventricular space. The animation follows the development of this same surface as the eyes emerge from the brain.

Sunrise in the Eye

Bottom image: Once the basic shape of the eye is specified, cells within the optic cup differentiate, populating the retina with neurons that sense light and refine the visual information before it is transmitted to the brain. In fish and amphibia, retinal stem cells are maintained throughout the animal’s lifetime in a stem cell niche located adjacent to the lens (yellow). Here in situ hybridization of a zebrafish eye (from a ~ 3-day-old larva) reveals gene expression patterns that distinguish retinal stem cells (red) from the cells that are becoming neurons (purple). By comparing gene expression patterns within the retinal stem cell niche in normal and mutant eyes, we gain insight into how stem cells turn into neurons.

Eyes are not only amazingly complex, but are reducibly so!


The Science of Linguistics

Linguistics is by definition the scientific study of language, but it’s been long debated whether it is a “soft” science. Science is the systematic study of the physical and natural world through observation and experiment, and hard sciences are generally perceived as more rigorous and accurate—i.e., natural, physical and computing sciences. “Soft” sciences are usually social, but linguistics seems to blur the line between the two—language is a social construct, but it’s also a complex, ever-evolving natural phenomenon, made up of dozens of sounds that combine to create thousands of words in thousands of different languages. Linguists study the use of language almost like animal behaviour is studied, and in recent years, modern linguistics has gravitated towards a “hard” science approach, focusing on accuracy, objectivity, and empirical data. Its many specialised subfields help enforce the rigour, such as phonology (the study of sound), syntax (the study of sentences), and semantics (the study of meaning), and linguistics also crosses disciplines to study the psychology, the neuroscience, and even the computer science of languageenabling the creation of language databases to analyse written and spoken patterns. However, hard sciences also have the capability to draw strong conclusions and make accurate predictions, and linguistics often deals with too many non-quantifiable variables to achieve either of these. For now, linguistics remains a soft science—but that doesn’t make it any less fascinating. After all, without language, we wouldn’t be able to communicate scientific ideas at all.

(Image Credit: 1, 2)

I only have some historical background knowledge on linguistics, mostly on how it shows human migrations, but the entire field seems fantastically interesting.