Scientists find way to map brain's complexity

LONDON Mon Apr 11, 2011 11:28am EDT

An image of superhighways in the brain, with the gold color showing a protein making up myelin, which speeds the conduction of electrical signals along nerve cells, allowing us to think more quickly. REUTERS/Courtesy of Professor David Attwell/UCL Neuroscience, Physiology & Pharmacology

An image of superhighways in the brain, with the gold color showing a protein making up myelin, which speeds the conduction of electrical signals along nerve cells, allowing us to think more quickly.

Credit: Reuters/Courtesy of Professor David Attwell/UCL Neuroscience, Physiology & Pharmacology

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LONDON (Reuters) - Scientists say they have moved a step closer to developing a computer model of the brain after finding a way to map both the connections and functions of nerve cells in the brain together for the first time.

In a study in the journal Nature on Sunday, researchers from Britain's University College London (UCL) described a technique developed in mice which enabled them to combine information about the function of neurons with details of their connections.

The study is part of an emerging area of neuroscience research known as 'connectomics'. A little like genomics, which maps our genetic make-up, connectomics aims to map the brain's connections, known as synapses.

By untangling and being able to map these connections -- and deciphering how information flows through the brain's circuits -- scientists hope to understand how thoughts and perceptions are generated in the brain and how these functions go wrong in diseases such as Alzheimer's, schizophrenia and stroke.

"We are beginning to untangle the complexity of the brain," said Tom Mrsic-Flogel, who led the study.

"Once we understand the function and connectivity of nerve cells spanning different layers of the brain, we can begin to develop a computer simulation of how this remarkable organ works."

But he said would take many years of work among scientists and huge computer processing power before that could be done.

In a report of his research, Mrsic-Flogel explained how mapping the brain's connections is no small feat: There are an estimated one hundred billion nerve cells, or neurons, in the brain, each connected to thousands of other nerve cells, he said, making an estimated 150 trillion synapses.

"How do we figure out how the brain's neural circuitry works? We first need to understand the function of each neuron and find out to which other brain cells it connects," he said.

In this study, Mrsic-Flogel's team focused on vision and looked into the visual cortex of the mouse brain, which contains thousands of neurons and millions of different connections.

Using high resolution imaging, they were able to detect which of these neurons responded to a particular stimulus.

Taking a slice of the same tissue, the scientists then applied small currents to subsets of neurons to see which other neurons responded and which of them were synaptically connected.

By repeating this technique many times, they were able to trace the function and connectivity of hundreds of nerve cells in visual cortex.

Using this method, the team hopes to begin generating a wiring diagram of a brain area with a particular function, such as the visual cortex. The technique should also help them map the wiring of regions that underpin touch, hearing and movement.

John Williams, head of neuroscience and mental health at the Wellcome Trust medical charity, which helped fund the study, said understanding the brain's inner workings was one of science's "ultimate goals."

"This important study presents neuroscientists with one of the key tools that will help them begin to navigate and survey the landscape of the brain," he said.

(Reporting by Kate Kelland; Editing by Sophie Hares)

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Comments (3)
Ralphooo wrote:
The photo caption says this is “one hemisphere of a healthy brain,” but it is not a fresh brain. Whatever health that specimen had is strictly in the past. A healthy living brain is pink, not that awful shade of yellow-brown. This one is thoroughly pickled and preserved for dissection.

Apr 11, 2011 4:27am EDT  --  Report as abuse
MrGameTheory wrote:
Following synaptic connections and understanding the function of cells through the study of localization is a tedious and logical approach towards understanding the brain and if we are lucky, consciousness. I wonder if the computer model provides any support to the idea that a specific part of the brain contains a cell that is central to mind. For background visit OfGrandeur.com

Apr 15, 2011 6:17pm EDT  --  Report as abuse
VoR wrote:
I believe that a deeper examination and understanding of the actions at the synapse hold the key to understanding the larger environment. At the synapse, as we all know, the action is electrical signal through the nerve -> exciting a chemical signal across the gap to chemical receptors on another nerve -> then transfered through that nerve as an electrical impulse. This, I believe, is a cycle that deserves deeper study as to the communication. Imagine that same action used as a mechanical device (dynamotor as an example). It would be: an electrical motor (nerve) -> gears or chain (synapse) -> electrical generator or dynamo -> (naturally feeds the motor). This is the beginning of an unlocked circuit or chain of events. There’s more to understand about the nature of simple actions and how they provide clues to a much broader understanding of the world around us.

Apr 16, 2011 10:57am EDT  --  Report as abuse
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