Remembering information for short periods would appear to be a simple task. However, new research discovers short-term human memory, often compared to random access memory (RAM) used in computers, is actually a complicated cognitive action.
Researchers agree that short-term memory is a complex cognitive act that entails the participation of multiple brain regions. However, whether and how different brain regions cooperate during memory has remained elusive.
German researchers have now come closer to answering this question. They discovered that oscillations between different brain regions are crucial in visually remembering things over a short period of time.
Scientists have known that brain regions in the frontal part of the brain are involved in short-term memory, while processing of visual information occurs primarily at the back of the brain.
The unknown factor is how the separated regions coordinate and integrate information to allow us to successfully remember information over a short period of time.
In a novel experiment, researchers recorded electrical activity both in a visual area and in the frontal part of the brain in monkeys.
The scientists then showed the animals identical or different images within short intervals while recording their brain activity. Afterwards, the animals had to indicate whether the second image was the same as the first one.
The scientists observed that, in each of the two brain regions, brain activity showed strong oscillations in a certain set of frequencies called the theta-band.
Importantly, these oscillations did not occur independently of each other, but synchronized their activity temporarily.
“It is as if you have two revolving doors in each of the two areas. During working memory, they get in sync, thereby allowing information to pass through them much more efficiently than if they were out of sync,” explains Stefanie Liebe, the first author of the study.
The more synchronized the activity was, the better could the animals remember the initial image. Thus, the authors were able to establish a direct relationship between what they observed in the brain and the performance of the animal.
Researchers believe the experiment shows that synchronized brain oscillations are important for the communication and interaction of different brain regions.
Investigators say that almost all multi-faceted cognitive acts, such as visual recognition, arise from a complex interplay of specialized and distributed neural networks. Research is ongoing in an effort to understand how the brain communicates both internal and external information.