Biological Brain-Twister Solved With 3D
While scientists have long understood why there are folds in the brain's outer layer, the how has remained a mystery.
The deep folds that give the adult human brain its wrinkled walnut appearance were Nature's solution to fitting a large, powerful processor into a small skull.
Like a piece of flat, square paper crumpled together to fit into a small, round hole, folding allows more neurons to be packed closer together, with shorter, faster connections between them.
While scientists have long understood why there are folds in the brain's outer layer, called the cerebral cortex or grey matter, the how has remained a mystery.
Do the creases develop as a result of genetic, biological or chemical signals? Or are they caused by physical forces?
On Monday, a team of researchers from the United States and Europe said the folds can be explained by physics -- a discovery that may have important implications for understanding certain brain disorders.
Folds in the cortex develop through buckling in weak spots which develop as the foetal brain grows, they said.
The brains of human foetuses are smooth for about the first 20 weeks, when folding begins and continues until the child is about 18 months old.
The surface area covered by the folded cortex is almost three times that of a smooth brain the size of our head, study co-author Lakshminarayanan Mahadevan from Harvard University in Massachusetts told AFP.
"The number, size, shape and position of neuronal cells during brain growth all lead to the expansion of the gray matter, known as the cortex, relative to the underlying white matter," he said by email.
"This puts the cortex under compression, leading to a mechanical instability that causes it to crease locally. This simple evolutionary innovation... allows for the thin but expansive cortex to be packed into a small volume, and is the dominant cause behind brain folding."
Mahadevan and a team used MRI scans of smooth foetus brains to build a three-dimensional gel model. They coated the surface with a thin layer of elastomer gel to represent the cortex.
To mimic brain growth, they immersed the gel brain in a solvent that was absorbed by the outer layer, causing it to swell relative to the deeper region.
Within minutes, folds started to appear that were remarkably similar in size and shape to the real thing, showing that the same process happened even though the model did not contain any living tissue.
"It looks like a real brain," said Mahadevan's colleague and fellow author Jun Young Chung.
A few other animals also have brain folds -- including chimpanzees, dolphins, elephants and pigs -- but the human brain is the wrinkliest of them all.
The physical explanation for brain folds was first proposed by Harvard scientists 40 years ago.
Now proven by Mahadevan's team, it was considered a controversial challenge at the time to the conventional wisdom that brain folds were created by purely biological, not physical, processes.
Commenting on the study, Ellen Kuhl of Stanford University's department of bioengineering, said the findings could be an important breakthrough in diagnosing, treating and preventing a range of neurological disorders.
Severe under- or over-folding, she said, can lead to seizures, motor dysfunction, mental handicap and developmental delay.
Knowing whether to target mechanical or biological causes should go a long way to developing better treatments.
This is a three-dimensional, gel model of a smooth fetal brain based on MRI images.
A new movement is underway that appeals to a group people unsatisfied with limits of their natural-born bodies. We're not talking plastic surgery here; we're talking bio-hacking. Bio-hackers are mainly interested in augmenting or improving their own biology or the biology of another living organism through the use of biotechnology and genetic engineering. The tools of the trade, once relegated to scientific laboratories, have come down in cost significantly, making do-it-yourself bioengineering and garage-based DNA sequencing available to anyone. Bio-hackers are fundamentally interested in altering the human condition -- usually for the better. We take a look at 10 extreme and not-so-extreme examples.
, known as the “DIY Cyborg,” implanted a Circadia 1.0 computer chip, which is the size of a smartphone, under the skin of his forearm. The chip monitors his vital signs, then transmits the data in real-time to his Android device via Bluetooth. The device is capable of, say, sending him a text when he’s getting a fever and then determining which factors are causing the fever.
implanted a near-field communication (NFC) chip -- roughly the size of a grain of rice -- in his hand to make it possible to enter buildings, log onto his PC instead of typing a password, and pay for goods. He was also in talks with a global IT security firm to experiment ways to use the chip in his hand to install malware on unsuspecting smartphones.
embedded a radio frequency identification (RFID) under his skin, between his thumb and index finger, to upload new GIFs onto the chip from his smartphone. The images are viewable only by cellphone; if he or others swipe a cell phone over his skin, they'll be able to get a glimpse of the digital tattoo.
, known as one of the first DIY RFID implantees in the world, has chips implanted in both of his hands. As a result, he can unlock doors, turn on lights and log into his computer just by swiping a hand. Graafstra also started
, an online store, where bio-hackers can purchase supplies for embedding technology into their own lives, and by lives, we mean "skin."
, Silicon investor and technology entrepreneur, spent $300,000 to hack his own biology. He set out to discover ways to manipulate his own biology and IQ. He used a variety of supplements and neuro-feedback training to upgrade his brain by more than 20 IQ points. He also lowered his biological age while learning to sleep more efficiently in less time. He biohacked his way toward losing weight without using exercise and invented Bulletproof Coffee, a coffee mixed with butter. Asprey is also the inventor of FATWater, a beverage infused with fat to allegedly help burn fat.
Two California biohackers,
, created an eyedrop made primarily of Chlorin e6, derived from a deep-sea bioluminescent fish. They claim the drops help them make out people over 160 feet away in complete darkness.
, MD, biohacker and author of “The Hormone Cure,” claims that anyone can biohack their hormones. She reportedly hacked her growth hormone (GH), which is the hormone that helps children grow taller as they age and impacts fat breakdown, cellular growth, muscle mass and protein synthesis in adults. Since studies have shown that decreased levels of GH can increase fat and lower energy, Gottfried set out to naturally raise her GH levels with exercise, specifically high-intensity interval training. With this type of exercise, also known as burst training, she increased her GH levels 53 percent, compared to her levels pre-burst training, over a six-week period. Gottfried incorporated a combination of other strategies as well, including cutting out excess sugar in her diet, taking melatonin supplements, increasing her sleep to at least eight hours per night and reducing stress through yoga.
, regarded as the world’s first cyborg, invented the Eyetap Digital Glass, which he now always wears. Mann allegedly augmented his vision, ability to capture and process images and make decisions by wearing the digital glasses.
and his team created
by synthetically cross-breeding Arabidopsis and marine bioluminescent bacteria. The biohackers assembled the genes virtually using a software called genetic compiler and sent the gene specs to DNA assembling companies to build the actual DNA. The team imported the genes by using bacteria Agrobacterium tumefaciens.
Biohackers from two California groups -- Counter Culture Labs (Oakland) and BioCurious (Sunnyvale) -- have engineered brewer's yeast to produce casein, a milk protein. The protein is mixed with water and vegan oil to make Vegan Milk. The milk is then turned into cheese using standard cheese-making methods.