People with chronic insomnia are constantly processing information in the brain and this is what interrupts their sleep.
How are the brains of people with insomnia different from those who sleep well?
The brain of people with insomnia has more activity, more capacity to adapt to change (plasticity) and greater excitability of neurons in the motor cortex (which is the part of the brain that controls movement), than people who do not have sleeping problems.
This is one of the conclusions of a study, published in the journal Sleep, in which the researchers examined 28 adults, 18 of them with insomnia, who were administered 65 electrical pulses of transcranial magnetic stimulation. This technique sends painless electrical impulses to the brain to stimulate the motor cortex, the region of the brain that controls involuntary body movements. Any involuntary movements of the thumb were measured, as well as the speed and direction of these movements.
For 30 minutes, the researchers trained the patients to be able to move their thumb in the opposite direction to the involuntary movement caused by the electrical impulse, and then reintroduced the electrical impulses.
The more ability the subject had to move the thumb in the opposite direction to the involuntary movement, the more activity and plasticity the motor cortex of the brain had.
The results showed that the brains of the participants who had chronic insomnia could be trained more easily than the brains of those who slept well, meaning they have higher levels of activity and plasticity in the region of the motor cortex.
What is not clear is whether this increase in the plasticity of the brain's motor cortex is one of the causes of insomnia or if it is part of a compensatory mechanism to try to combat the problems related to chronic insomnia. Chronic insomnia can cause an increase in metabolism and cortisol levels, which could be related to the greater plasticity of the brain of people with insomnia.
Salas RE, Galea JM, Gamaldo AA, Gamaldo CE, Allen RP, Smith MT, et al. Sleep (2014). More information.
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