If you’re forgetting things that have happened just recently, blame your lack of sleep!
Lack of sleep, or sleep deprivation, hinders the process of new memory formation, says a new study published in the journal Science.
Humans can’t live without sleep—we need to temporarily lose our souls so that we can get re-energised. Sleep is a necessity that is wrapped in innumerable benefits, as science has shown over time. The new study further supports previous research that points out the paramount importance of sleep in building memory, and learning. A team from Johns Hopkins Medicine studied mice, and found that sleep does impact positively on brains cells involved in memory and learning, as many other studies have suggested. The findings also include completely new information: molecules participating in these processes have been discovered, and the adverse effects of sleep deprivation, sleep disorders, and sleeping pills on memory building have been revealed.
The authors explain that the brain cells responsible for memory and learning need to be re-calibrated so that the information input is not eventually lost. Sleep allows for this re-calibration, and therefore, a lack thereof endangers the storage of memories, explains lead researcher Graham Diering.
Memories are “contained” in synapses, the gaps in between neurones that allow the latter to communicate, and pass information to each other. This signalling occurs through a chemical called a neurotransmitter which is released from one end of the synapse (the sending side) to the other (the receiving side). Thus do messages travel. Synapses on the receiving side can be weakened or strengthened through the removal or addition of receptor proteins, which determines whether they receive more information or less input, which in turn affects memory: these synaptic changes are thought to control memory encoding. On the other hand, if neurones are repeatedly firing, they might not be able to function efficiently, thereby curbing memory encoding and learning. This does not happen, allegedly because of a process known as homeostatic scaling down, whereby synapses are relatively weakened so that no overloading happens. Diering and his team wanted to find out whether this process actually occurred in sleeping mammals. They, therefore, examined specific regions of the mouse brain involved in learning and memory. Proteins taken from synapses from the hippocampus and the cortex of the brains of sleeping and awake mice were analysed.
The findings show that the concentration of receptor proteins decreased by 20% in sleeping mice. This implies a general weakening of synapses, as opposed to awake mice.
“That was the first evidence of homeostatic scaling down in live animals,” says co-researcher Richard Huganir. “It suggests that synapses are restructured throughout the mouse brain every 12 hours or so, which is quite remarkable.”
The re-structuring of the synapses, the re-calibration, caters for the encoding of memory so that new ones are not lost because of too much firing from the neurones.