Humans willingly delay sleep all the time. We stay up late for parties, we pull all-nighters to study for tests but going without sleep for too long will actually kill you and we notice partially because of one particular Italian family.
In the 1800’s, a Venetian man named Giacomo fell mysteriously ill. He suffered from dementia and an inability to sleep, and then he died. He passed on his condition to his descendants, and the disease still runs in the family today.
When scientists were finally able to identify the cause of 1970’s, they uncovered an extremely incurable disorder that they called Fatal Familial Insomnia (FFI). The main symptom of this disorder is progressive insomnia which causes hallucinations, delirium, and is ultimately fatal.
Even though it is super rare, we know which genetic mutation causes the disease. Researchers think this mutation causes damage to a brain region called the Thalamus, which is known to regulate sleep and consciousness. The growing inability to sleep then leads to death because the body is never able to rest. With metabolism and high gear all the time, organs start to fail. It’s possible that patients with FFI die from more than just sleep deprivation.
Studies done on rats in the 1980’s confirmed that sleep deprivation on its own is fatal. Rats who were kept from sleeping developed all kinds of metabolic problems like weight loss increased metabolism, increased metabolism and fluctuating body temperatures and within two to three weeks all of the sleep-deprived rats were dead. Researchers still aren’t quite why we sleep, but we do know that not sleeping is deadly. We also know that it helps you consolidate memories. But biologists didn’t realize that sleep was critical for helping store memories until about a hundred years ago.
In 1920’s, a group of researchers taught subjects a list of nonsense words. People who got a good night’s rest were better at remembering the list than people who didn’t get to sleep between learning the list and picking the test. His research sparked a wave of studies that found a strong connection between certain kinds of memory and sleeping. There are different kinds of memory which rely on different brain circuits.
Declarative memories are memories of events and facts, and they depend on an area of the brain known as the Hippocampus. They’re separate from non-declarative memory – the kind of memory that builds habits and motor skills like playing the piano. It turns out that sleep is of particular importance for helping the brain retain declarative memory. So the teachers who tell you to sleep the night before are right, it’s essential for remembering facts and figures.
Other studies have discovered that the detective sleep that’s important for this process is what’s called non-REM sleep or the non-rapid eye movement sleep, even though you might relieve your classes in your dreams.
It’s actually when you’re not dreaming that your brain is hard at work solidifying those memories your brain is super active when you’re sleeping which also might seem like old news. The biologists didn’t know that until the 1920’s either when they stuck electrodes on people’s scalps to noninvasively record brain activity since it feels like your mind is shutting down when you’re sleeping.
Scientists had figured that the brain goes silent, but once they sort of actually monitoring brain activity, they learned that it is not what’s happening at all. They use a new technique called EEG; it records the electrical signals that come from neuron activity in the brain when they register in people’s brains while they slept. They discovered that instead of silence the sleeping brain is dominated by big slow waves of activity. More research has picked apart how different stages of sleep are associated with different wave patterns and helped clarify the difference between REM sleep and non-REM sleep.
The idea that the brain is active during sleep and that different sleep states correspond to different kinds of waves patterns change the way biologists thought about sleep and helped drive lots of future sleep research around the same time scientists.