Now, a computer that daydreams just like humans

Scientists have developed a virtual model of the brain that daydreams like humans do, a finding that can help better diagnose and treat brain injuries.
Researchers created the computer model based on the dynamics of brain cells and the many connections those cells make with their neighbours and with cells in other brain regions.
They hope the model will help them understand why certain portions of the brain work together when a person daydreams or is mentally idle. This, in turn, may help doctors better diagnose and treat brain injuries.
"We can give our model lesions like those we see in stroke or brain cancer, disabling groups of virtual cells to see how brain function is affected," said senior author Maurizio Corbetta from the Washington University.

"We can also test ways to push the patterns of activity back to normal," said Corbetta.
Researchers identified several "resting state" brain networks, which are groups of different brain regions that have activity levels that rise and fall in sync when the brain is at rest.

They have also linked disruptions in networks associated with brain injury and disease to cognitive problems in memory, attention, movement and speech.
The new model was developed to help scientists learn how the brain's anatomical structure contributes to the creation and maintenance of resting state networks.
The researchers began with a process for simulating small groups of neurons, including factors that decrease or increase the likelihood that a group of cells will send a signal.

Based on data from brain scans, researchers assembled 66 cognitive units in each hemisphere, and interconnected them in anatomical patterns similar to the connections present in the brain.
Scientists set up the model so that the individual units went through the signalling process at random low frequencies that had previously been observed in brain cells in culture and in recordings of resting brain activity.
Researchers let the model run, slowly changing the coupling, or the strength of the connections between units. At a specific coupling value, the interconnections between units sending impulses soon began to create coordinated patterns of activity.

The study was published in The Journal of Neuroscience.