It’s well know that sleep deprivation can cause a host of problems from inattention to depression and even certain illnesses. A lack of sleep has been shown to affect the immune system making us more susceptible to colds, flu and even cancer. Insomnia is a common complaint in older people as well as those in high stress occupations. “Drowsy driving” is a factor in approximately 100,000 accidents each year in the United States.
New research shows another problem that occurs when a person does not get enough rest. Lack of sleep can lead to physical changes in the brain. A team at the University of Frieiberg has recently published their findings on sleep and how it impacts brain connectivity. In the brain, communication is between neurons, which are connected by synapses. These pathways allow the brain to read, to make decisions and to control the muscles. Lead author Christopn Nissen worked with 9 women and 11 men and tested them to see how the neurons fired after a sleepless night and a night when they’d had adequate rest.
The study focused mostly on the motor cortex which is the area of the brain that controls movement. Using magnetic pulses, neurons in the brains of the participants were activated. In patients that had been sleep deprived, producing a muscle response required a much lower magnetic pulse. This indicated that in sleep deprived brains, the neurons were in an excitable state.
The participants who had a full night of rest needed more magnetic current to trigger a muscle response. In addition to the changes in neuronal activity, when asked to complete memory tests and other cognitive tasks, those who had been asked to stay awake performed at much lower level than their well rested cohorts.
The theory that sleep regulates the strength of synaptic connections has been around for a while, but Nissen’s research is the first to show synaptic activity directly. It also backs up the theory developed in 2003 known as synaptic homeostasis hypothesis or SHY. It states that when we are awake, the synapses that form connections between our brain cells get stronger and stronger when we are awake and absorbing information over a long period of time. It requires a lot mental energy and if the brain does not rest, the synapses cannot keep up. Much like an athlete who trains too hard and doesn’t allow for muscle recovery, not enough sleep buts a burden on the neuronal network and eventually it can simply give out.
Blood tests that were done on the participants also showed reduced levels of of BDNF, a molecule that is involved in signaling synapse and regulating brain plasticity. In an interview with The Guardian, Nissen said, “Why we sleep is a fundamental question. Why do we spend so much of our lives in this brain state? This work shows us that sleep is a highly active brain process and not a waste of time. It’s required for healthy brain function.” The video below gives more detail on how to get a good night’s sleep.
Sources:
The Guardian,
Nature,
Sleep Foundation
