A new study in the US found that high-frequency “fluctuations” lasting one-tenth of a second synchronize distant regions of the brain, combining fragmented information into a single thought or memory. Researchers at University of California San Diego recorded the activity of 1373 neurons in the brains of 35 patients undergoing treatment for drug-resistant epilepsy. During memory tests, these bursts, reaching 90 oscillations per second, were found to occur simultaneously at distant points in both hemispheres. The shared rhythm increased by 30% to 49% the likelihood that neurons located up to 22 centimeters apart would transmit signals synchronously. As the memory load increased, the rhythm also became more frequent. The researchers stated that the mechanism was not dependent on a single command center.
Why it matters
The findings make it more difficult to explain memory and thought as processes managed solely by a single brain region; timing between different regions plays a decisive role in integrating fragmented information. This framework is particularly important for neuroscience research seeking to understand how communication in the brain is organized as the amount of information increases. However, because the data were obtained from patients undergoing treatment for drug-resistant epilepsy, the question of to what extent the same process applies to people without epilepsy remains open. In addition, although the shared rhythm was found to increase information transfer between distant neurons, it has not yet been explained how this creates the content of a specific memory or the meaning of a thought.