Diving within our brains
Humans have managed to a probe launched from Earth land, after a journey of 6,000 million kilometers through space on a comet crosses the solar system 135.000 mph. However, that same human being is incapable of understanding his own brain. The organ that weighs 1.5 kg we have in the head is a complete stranger. No tools to study it. It contains 86,000 billion neurons, with trillions of connections between them. With current technology, it is impossible to cover it. It is like trying to understand the universe looking out the window at the Big Dipper.
But this situation of powerlessness may be short. In April 2013, US President Barack Obama announced the BRAIN project, an initiative of 4,500 million dollars until 2022 to “give scientists the tools they need to get a dynamic picture of the brain in action and understand how we think, learn and remember “.
BRAIN started on October 1, 2014, when laboratories, including some from the National Institutes of Health US and Research Defense Advanced Research Projects Agency (DARPA, the greatest exponent of military science) started receive dollars. In its first fiscal year, BRAIN began offering its first results.
Neuroscientists already peek the brain as never before had. One of them is Charles Lieber of Harvard University. His team presented in June in the journal Nature Nanotechnology a very flexible electronic device that can be implanted in the brain of mice with a microsyringe. This technique, revolutionary, can be covered with a mesh electrode cortex to record real-time neural electrical signals.
“This injectable electronic device has a structure in the form of mesh on a larger scale, look like a mosquito net which put on the windows to keep out the bugs. As a mosquito net, which is very flexible and you can easily see through our electronic device in a mesh is open in 90% of its surface is almost invisible in a glass of water”, says Lieber.
“And it’s almost a million times more flexible than the more flexible electronic devices studied by other researchers. Its flexibility and its spaces make our device closely resembles the nervous tissue and therefore does not cause reaction in the brain tissue once implanted”, he explains.
Possible applications are formidable. And not only to understand the brain. The device could also be used “to stimulate neural activity in deeper brain regions relevant to Parkinson’s disease”, said Lieber.
Young Evan Macosko, of Harvard Medical School, also located on the front line of the BRAIN project. Every cell in our brain custody inside a copy of all our genes. But each cell just read certain pages of this manual. A muscle cell using genes that allow it to contract. A kidney cell used to filter the blood that enable
“I still do not understand many of the functions of brain cells. If we know which genes are using, we could better understand their roles and how they are classified”, said Macosko. Said lighter, still do not know how many types of cells are in our brain or how many there are of each.
Macosko team introduced in May in the journal Cell, the Drop-seq, a technology that identifies which genes are using a cell, or the tens of thousands of cells in a tissue sample. “Our next step is to use Drop-seq to create an atlas of the brain cells, a detailed list of the types of cells that are present in each brain region”, he adds. An atlas and open the door to better understand the functions of different brain areas, but before Macosko and his men will have to refine the shooting: At this time, Drop-seq detects only 12% of the genes used by each cell.
The molecular biologist Bryan Roth of the University of North Carolina, is one of the scientists at the forefront of BRAIN. His team designs in his laboratory cell receptors, a kind of nightclub doormen cells. These synthetic guardians, known as DREADD, can be placed in brain cells to activate and deactivate them by remote control drugs.
“Basically, they allow us to take remote control of brain cells. Can turn them on or turn them off to understand how the brain works”, explains Roth. His approach is similar to optogenetics, another technique at the frontier of knowledge: scientists installed algae genes sensitive to light in virus that injected into rats or monkeys skulls. Once placed in neurons of animals, genes produce a protein that makes the cell switch, activating or deactivating a function of laser light bursts released by researchers.
Optogenetic problem is that it requires invading the skull to introduce laser light. And DREADD also have an Achilles heel, Roth admits: “We are not allowed rapid control of cellular activity, are slower than optogenetics”.
The group of molecular biologist has just presented a new DREADD, more sophisticated, in the journal Neuron. “The drugs we use do nothing to animals beyond power cycle neurons”, he says. The DREADD, and other emerging technologies of BRAIN initiative may be for the telescope brain was for the universe.