The mechanism of visual working memory is revealed

In the experiment, the animals played a video game: a set of colorful squares appeared on the screen, then disappeared and returned a second later — but one square changed color. The subjects needed to look at the changed object as quickly as possible. The experts recorded the reaction, gaze direction and brain activity in the area responsible for eye movement.

It turned out that the accuracy and speed of the reaction depended on which phase of the theta wave the brain was in at the time of the appearance of the altered square, and on the height of its location on the screen. Each part of the visual field had its own optimal wave phase, at which attention and memory worked better.

The authors compare this process to a moving wave that runs through the cerebral cortex, sequentially activating different areas like a radar beam. When the change coincided with the desired phase of the wave, the animal noticed it faster — if not, the reaction was delayed.

Miller’s lab has previously shown that the brain uses different wave ranges to solve cognitive tasks. In the study, scientists confirmed:

• Theta rhythms control attention and working memory;
• Beta waves (8-25 Hz) set the “rules” of the task, structure thinking;
• Gamma waves (30 Hz and higher) encode incoming sensory information.

When the theta wave was in the arousal phase, the activity of beta rhythms decreased, and signals from the sensory organs were perceived more clearly. In the inhibition phase, on the contrary, beta increased, and the reaction weakened.

Interestingly, the more objects needed to be stored in memory, the stronger the effect of theta waves. This observation may have clinical significance: in disorders associated with low activity of theta rhythms, the ability to concentrate and memorize visual information suffers. In the future, this may lead to the creation of neural interfaces capable of correcting brain waves and improving cognitive functions.

The results confirm the hypothesis that the brain does not work as a digital computer, but as an analog system, where rhythms and waves form a flexible, self-organizing environment for computing. These rhythms may explain why human attention and memory are so variable — and why at one moment we see everything, and at another we do not notice the obvious.