Good sleep is necessary to purify memories

A new study sheds light on the relationship between sleep and memory as it suggests our brain gets rid of unimportant memories. Why? To make room for fresh, new learning the next day. How the brain does this lies in our synapses in our cerebral cortex and that good night’s sleep.

What Are Synapses?

Synapses are the communications points between two neurons, the nerve cells that make up our nervous system. One neuron sends signals to another neuron through these synapses via a complex system of channels, synaptic vesicles, neurotransmitters, and more. Synapses vary in sizes and the bigger the synapse, the stronger it is. This is because bigger synapses contain larger numbers of neurotransmitters and other structures that make up the synaptic junction. These bigger synapses hold those memories our brain doesn’t want us to forget. The cerebral cortex, the four lobes (frontal, parietal, temporal, and occipital) of the brain, packs in hundreds of trillions of neurons, all communicating with each other through the synapses.

At the basic level, synapses are the storage facility for our memories, but unlike boxes of trinkets we might store in the attic and forget, the storage in our synapses is living and changing, strengthening as we learn new things and weakening as we forget. From the perspective of our mind function, synapses give us our individual human complexity and what makes us unique.

Now, according to one study, it appears that each night as we sleep, our brain is hard at work purging our weak synapses of the memories the brain deems unimportant and resetting those synapses for the next day.

Sleep and Memory: Study Shows Weak Synapses Decrease in Size During Sleep

The study’s purpose was to investigate how sleeping affected the synapses in the brain, specifically, did synapses weaken during sleep? A total of 6,920 synapses in the brains of mice were studied. The results? Synapses decreased in size by 18% during sleep. So the synapses that strengthen as we learn new things throughout the day weaken as we sleep at night. However, researchers observed that the larger synapses remained stable while the weaker synapses were the most affected, suggesting those weaker memories we don’t need are the ones purged from our brains while we sleep, while the stronger memories remain intact.

What You Can Do to Keep Your Brain Cells Healthy

There are a number of things you can do to keep your brain cells healthy. First get good quality sleep so your brain has plenty of off-line time to reset those synapses. Second, keep learning. You may not be in school, but that doesn’t mean learning has to stop. Learn a new language, skill, hobby, or sport. Read books that challenge you, and, yes, look up those words you don’t know. Start playing a new instrument, or better yet, relearn that saxophone you haven’t picked up since high school. Any learning that requires practice and repetition will bulk up those good, strong synapses in the brain. Third, turmeric has been shown to keep the brain healthy by regenerating nerve cells. And, finally, toss the nerve-damaging medications if possible. Statins are a big one as we know these drugs actually kill nerve cells.

The upshot? While we may have thought that a good night’s sleep was all about re-energizing our bodies and helping us be more alert and ready to face the next day, the relationship between sleep and memory demonstrates it may be about so much more. Retention and learning takes lots of practice and dedication, and, thankfully, it appears that our brain knows to clear the clutter from our weaker synapses as we sleep so we have plenty of room to store the important stuff.