Thaindian News

London, April 11 (ANI): Researchers have moved a step closer to being able to develop a computer model of the brain.

They have developed a technique to map both the connections and functions of nerve cells in the brain together for the first time.

By mapping these connections - and hence how information flows through the circuits of the brain - scientists hope to understand how perceptions, sensations and thoughts are generated in the brain and how these functions go wrong in diseases such as Alzheimer’s disease, schizophrenia and stroke.

Mapping the brain’s connections is no trivial task, however: there are estimated to be one hundred billion nerve cells (’neurons’) in the brain, each connected to thousands of other nerve cells - making an estimated 150 trillion synapses.

Dr Tom Mrsic-Flogel, a Wellcome Trust Research Career Development Fellow at UCL (University College London), has been leading a team of researchers trying to make sense of this complexity.

“How do we figure out how the brain’s neural circuitry works?” he asked.

“We first need to understand the function of each neuron and find out to which other brain cells it connects. If we can find a way of mapping the connections between nerve cells of certain functions, we will then be in a position to begin developing a computer model to explain how the complex dynamics of neural networks generate thoughts, sensations and movements,” he added.

“We are beginning to untangle the complexity of the brain,” said Mrsic-Flogel.

“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 it will take many years of concerted efforts amongst scientists and massive computer processing power before it can be realised,” he added.

The researchers 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, for example a horizontal edge.

Taking a slice of the same tissue, the researchers then applied small currents to a subset of neurons in turn to see which other neurons responded - and hence which of these were synaptically connected. By repeating this technique many times, the researchers were able to trace the function and connectivity of hundreds of nerve cells in visual cortex.

The study is detailed in the journal Nature. (ANI)