The brain actively reactivates and replays memories during sleep, which allows for the consolidation and improvement of memory.

noli's read

This mechanism, known as 'neuronal replay,' is a concept widely supported by modern neuroscience. Studies in rodents (e.g., the work of Wilson and McNaughton) and human imaging research have demonstrated that neuronal activity patterns observed during learning repeat during sleep, particularly during deep sleep phases. This process is essential for the transfer of information from short-term memory to long-term storage. While the 'printed circuit' analogy used by Matthew Walker is a metaphorical simplification, it illustrates the strengthening of synaptic connections (plasticity) quite accurately. Science confirms that sleep deprivation truly hinders this replay process, impacting information retention. There is no notable exaggeration here, as the consolidating role of sleep on memory is a robust scientific consensus.

the sources

No named source held this one up — that absence is part of the verdict.