Scientists Reveal New Model of Brain: Thought Processes Mapped

The brain can look like a chaotic place if you don't know what you're seeing. Individual neurons apparently fire off at random, not corresponding to a simple stimulus or response linkage. Now, though, researchers have created a new model--or map--of the brain that explains this apparently chaotic activity.

In order to actually create this model, scientists looked at the brains of rhesus monkeys. These apes are closely related to humans, which makes them a perfect example to use when studying the brain. The researchers focused their attention on the activity patterns of 237 neurons that had been recorded using electrodes implanted into the frontal lobes of the apes.

Yet the researchers wanted to examine brain activity, which meant that something had to spark it. The apes were taught to recognize images of different objects on a screen. When they were shown these images, about one third of the neurons demonstrated mixed selective activity.

A mixed selective neuron is one that does not always respond to the same stimulus. For example, the neuron didn't respond the same way to the picture of a sailing boat or a flower. Instead, its response differed as it took account of the activity of other neurons. The cell adapted its response according to what else was going on in the ape's brain.

So what does this mean exactly? Just as individual computers are networked to create concentrated processing and storage capacity in the field of Cloud Computing, so too are the neurons of the brain. The links in the complex cognitive processes that take place in the prefrontal cortex play a key role. In addition, the researchers found that the greater the density of the network in the brain, in other words the greater the proportion of mixed selectivity in the activity patterns of the neurons, the better the apes were able to recall the images on the screen. Mixed selective neurons are important in rhesus monkeys, and so are also probably important in our own brains 

"When you zoom out from looking at individual cells and observe a large number of neurons instead, their global activity is very informative," said Mattia Rigotti, a scientist at Columbia University, in a news release.

The findings reveal that brain research shouldn't just be satisfied with simple activity patterns. Instead, it should take the chaotic patterns into account, as well. Together, they can reveal a larger picture that puts the chaos into context.

The findings are published in the journal Nature.