Neuroscientists listened to people’s brains for a week. They found order and chaos.

Ghuman, Wang and their colleagues looked to people undergoing brain surgery for epilepsy. Some people with severe or otherwise incurable epilepsy choose to have the small parts of their brain that trigger their seizures surgically removed. Before any operation, electrodes can be implanted in their brain for about a week. Meanwhile, these electrodes monitor brain activity to help surgeons pinpoint the onset of their seizures and identify exactly which part of the brain needs to be removed.

The researchers recruited 20 of these people to volunteer in their study. Each person had 10 to 15 electrodes implanted for 3 to 12 days.

The pair collected recordings from the electrodes throughout the period. The volunteers were all in the hospital while they were being watched, but they were still doing everyday things like eating meals, talking to friends, watching TV or reading books. “We know so little about what the brain is doing during these real, natural behaviors in a real environment,” says Ghuman.

The edge of chaos

The team discovered surprising patterns of brain activity over the week. Specific brain networks seemed to communicate with each other in what felt like a ‘dance’, with one region appearing to ‘listen’ while the other ‘talk’, say the researchers, who presented their findings at the Society’s annual meeting for Neuroscience in San Diego last year.

And while the volunteers’ brains seemed to switch from one state to another over time, they did so in a curious way. Rather than simply switching from one activity pattern to another, their brains seemed to jump from one state to another, seemingly at random. When the brain shifts from one semi-stable state to another, it seems to embrace chaos.