Sometimes in the case of nightmares, sleep evokes feelings that we normally repress. People with PTSD often experience Terrible memories are coming back. For them, night after night that adversely affects their sleep and further affects their mental health.
Virginia Tech researchers, who published their findings in the journal J Neurosci, Now claim to understand people with why Post-traumatic stress disorder Keep dreaming about these disturbing events.
According to researchers, PTSD puts the brain in a vicious loop. Brain activity increases during rapid eye movement (REM) sleep, which can cause the brain to behave similarly when a person is awake. According to Virginia Tech neuroscientist Sujit Vijayan, the brain can actually be more aware during REM sleep than it is when you’re actually awake, thus earning it the label “paradoxical sleep.”
The neurotransmitters norepinephrine and serotonin, known to promote alertness, often decrease in concentration during REM sleep. Rhythm communicates between the frontal lobes of the brain and the amygdalaA region linked to emotional expression, Vijayan and team linked lower levels with the brain’s ability to inhibit fear-expressing cells. These levels are still elevated in PTSD individuals.
So, the researchers looked at how the level of sleep in PTSD patients might affect these fear-related rhythms.
Research models show that, contrary to what happens in healthy individuals, these increased levels allow traumatic memories to freely travel through the brains of PTSD patients. According to this study, patients may need high-frequency rhythms to forget these memories, suggesting a potential therapeutic target.
The problem is that non-REM sleep, which represents the transition stages from light to deep sleep, has been the focus of many sleep neuroscience studies. In light of what is known about REM sleep in relation to memory, Vijayan calls it the “Wild West.”
“REM sleep is very difficult to capture,” said Vijayan, an assistant professor in the Virginia Tech College of Science’s School of Neuroscience, in a university release.
“There are really good models of how non-REM sleep can consolidate memories and what role it plays in learning and memory. But when we talk about REM, there are no real, good models. How are these things happening?
To regulate the rhythm during these trials, the scientists lowered norepinephrine and serotonin levels to reflect normal REM sleep. They discovered that doing so effectively blocked memories of the terror. More specifically, the scientists discovered that inhibiting fear-expressing cells was most successful when a specific frequency of the brain’s rhythm was used.
Theta rhythm
Theta rhythm of about four hertz, the basic unit of frequency, was most effective in increasing connections between brain regions needed to suppress fear memories.
Theta rhythm helps coordinate the activity of areas of the brain related to learning and memory. They usually range from four to eight hertz in people. The second experiment replicated the earlier settings by simulating REM sleep in PTSD patients. They were surprised to find that they did not see the same patterns.
“I’m a little surprised that four hertz didn’t work,” Vijayan added. “I thought it might still be useful, but it really wasn’t.”
Scientists have discovered a useful way to help PTSD patients sleep better by simply focusing on these rhythms. Even other brain disorders can benefit from this concept.