American scientists have announced that they have created the most complete three-dimensional "map" of neuronal interconnections inside the brain of a mammal, namely a mouse. It is still a significant advance in the long-term attempt to understand the way the brain works and its neurodegenerative diseases. But to become an analogue "χάρτης"For the human brain, it will take several more years.
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Researchers led by Hongui Zeng of the Allen Institute for Brain Science in Seattle, published in the journal Nature, according to Reuters and New Scientist, described the creation of a "landmark" as a "milestone". detailed "map" (Allen Mouse Brain Connectivity Atlas) with all the interfaces, which form the various functional circuits of the brain.
As University of Washington - St. Louis neuroscientist David van Essen put it, "this is the most detailed analysis of the brain 'connectivity' we have today for any mammalian brain." The "map" shows how the millions of neurons (brain cells) connect and communicate with each other through their extensions (axons) to produce memories, behaviors and emotions. The anatomical and functional problems of these circuits cause brain diseases.
Before this "map" of the mouse brain, scientists only had the complete - but much simpler - neuronal "connectivity" of the worm C.elegans, which has just 302 neurons. In comparison, O brain the mouse contains 75 million neurons and the human brain has around 85 billion neurons, each of which makes up to 10.000 connections with other neurons.
The "mapping" of the mouse brain was accomplished with the help of viruses, through which a fluorescent protein was introduced into the animal's brain, which "illuminated" the neural circuits under the microscope. Among other things, it has been found that neural connections that are limited to only one hemisphere of the brain are always stronger than those that extend to both hemispheres.
To be "mapped", the mice's brains were cut into 500.000 cubes, each measuring 100 micrometers (millions of meters). This "map" has further room for improvement in terms of analysis, as it "tracks" the connections between tiny areas of brain tissue (each containing 100 to 500 neurons), but does not include the exact connections (synapses) of all the individual neurons to each other.
Such a sharpening "map" to the human brain (cell to cell) is the ultimate goal. It is, however, assumed that, apart from many similarities, such a "map" will be unique to each individual person, in the same way that each of us is a unique personality.
The gene's "atlas" of the human embryonic brain
Besides, in a second one study, επιστήμονες επίσης από το Ινστιτούτο Άλεν, που έκαναν τη σχετική δημοσίευση στο ίδιο περιοδικό, έδωσαν στη δημοσιότητα τις πρώτες λεπτομερείς τρισδιάστατες pictures των σταδιακών φάσεων ανάπτυξης του εγκεφάλου του εμβρύου μέσα στην μήτρα. Η έρευνα, στο πλαίσιο του προγράμματος “BrainSpan Atlas”, ελπίζεται ότι θα βοηθήσει στην κατανόηση των διαταραχών που «πυροδοτούνται» πριν από τη γέννηση, όπως η σχιζιφρένεια και ο αυτισμός.
The researchers, led by Ed Lin, analyzed the brains of four human embryos, which were between 15 and 21 week of pregnancy, thus creating the first "atlas" of sequential gene changes in the developing brain, which genes are activated and they are deactivated sequentially as the brain develops.
“That was just the beginning. We want to understand the plan with base which we 'build' a brain, and this was the first step in that direction, as we began to create a map of how genes drive the whole process," said Ed Line. "Knowing where and when a gene is expressed in the brain can provide us with important clues about its role."
In the future, when neuroscientific research will have gone further, scientists hope they will be able to compare the human brain with other mammals, such as monkeys and mice, to understand where human specificity is. The ultimate goal is to discover the neurobiological basis of the greatest of all mysteries: human consciousness.
Link: For original scientific papers (subscription) at the following addresses:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13186.html and
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13185.html
News Room «Profit»With information from RES - AMP
