Scientists from the Chinese Academy of Sciences, Peking University and the Shanghai Center for Brain Science and Brain-Inspired Technology, together with a team of international collaborators, made their discovery through experiments on macaques, with the findings published in the journal Science on Friday.

The research team trained macaques, as a non-human primate model, to remember sequences consisting of multiple spatial locations and used in vivo two-photon calcium imaging to record neuronal activity in the prefrontal cortex of the macaque brains.

According to the published article, the animals were shown a sequence of three dots and, after a delay, they made a saccade to the corresponding locations in the appropriate order.

The animals temporarily stored the sequential information in their brains during the delay and the researchers recorded their neural activity.

The researchers speculated that the brain created three virtual "screens" in the prefrontal neurons, allowing the animals to remember which dot appeared first and which came later. In this way, the information presented on a single screen could be stored as three separate "screens" in the brain.

The results suggest that the "screens" are stable and in general use, and are distributed across large overlapping neural groups rather than on single neurons.

Also, the screens are thought to share ring structures, although the ring diameter tends to contract as the sequences add up.

The scientists posited that there is a reduced degree of discrimination in the smaller rings, so the information that comes later is given less attention. This would explain why one's memory becomes less reliable as more information is added, according to the researchers. 

Source: Xinhua