New Research Reveals How Our Brains Encode Memories While We Sleep

According to new research recently published in the journal Science, scientists have come even closer to fully understanding how the brain compiles memories during sleep. 

 

While it was previously believed that the delta waves – the slowest type of brainwaves – emitted while we sleep have been general periods of silence, scientists at the Center for Interdisciplinary Research in Biology at College de France have determined they actually  “isolate assemblies of neurons that play an essential role in long-term memory formation,” according to Science Daily, making them “instrumental for memory consolidation”.

 

When we sleep, neurons in the cortex oscillate between periods of activity and perceived neural silence. 

 

In a rat model, the scientists observed that, after the expected spike of cortex activity, ensuing delta waves and neural silence, some cortical neurons actually remained active while the rest slept.

 

 According to IFLScience.com, the study authors trained rats to perform a spatial memory task and recorded their hippocampal and cortical activity during said task and during the first two hours of sleep. During the sleeping hours, the rats  hippocampi repeated the activity patterns they had displayed during the memory task. “By observing this process, the team discovered that the activity patterns within the hippocampus actually predicted which cortical neurons would remain active, allowing them to watch in real-time as short-term memories in the hippocampus were recorded as stable memories in the cortex,” Ben Taub writes. 

 

To confirm their findings, the researchers artificially stimulated the cortices of the rats, “causing the wrong neurons to remain active during the delta phase, and found that this prevented the animals from being able to complete the spatial memory task the next day.”

The scientist noted, “The study substantially change how we understand the cortex.”

 

Read the full study here.