- Sleep deprivation is generally known to have a negative impact on mood, but a new study has found a paradoxical effect.
- The research revealed that a single night of complete sleep deprivation led to increased connectivity between the amygdala and the anterior cingulate cortex in the brain, resulting in improved mood in certain individuals, including those with major depressive disorder.
- The findings suggest that understanding this brain connectivity could provide potential targets for interventions in depression treatment and shed light on the relationship between sleep and mood regulation.
In a new study published in PNAS, researchers utilized resting-state functional magnetic resonance imaging (RS fMRI) to map brain activity in specific regions, aiming to understand why certain individuals experience a positive mood enhancement after a period of sleep deprivation despite most people generally experiencing a negative impact.
Lack of sleep is a widespread problem that negatively affects the mood and well-being of billions of people worldwide.
According to the researchers, sleep deprivation can actually lead to a rapid and significant improvement in mood for some individuals with depression.
To investigate why this happens, they looked at how certain parts of the brain are affected by sleep deprivation in people with and without depression.
Amygdala, a region of the brain, may be key
They focused on the amygdala, which is involved in controlling emotions, and the dorsal nexus (DN), which is important for regulating mood in people with depression.
They discovered that the amygdala, an important brain region involved in depression, is influenced by a lack of sleep.
This new research demonstrates that a single night of total sleep deprivation strengthens the connectivity between the amygdala and the anterior cingulate cortex, which is associated with improved mood in both individuals without depression and those with the condition.
The researchers used RS fMRI, allowing them to see how different brain regions are connected while people rest.
They compared the brain activity of healthy adults and people with major depressive disorder after one night of total sleep deprivation in a controlled lab setting.
The results showed that losing a night of sleep made healthy participants feel more negative, but interestingly, it reduced depressive symptoms in 43% of patients with depression.
Sleep deprivation showed increased connectivity on MRI
When they looked at the brain scans, they saw that sleep deprivation increased the connectivity between the amygdala and the DN in healthy participants.
Notably, the researchers found that when the amygdala was more connected to the anterior cingulate cortex (ACC) after sleep deprivation, healthy participants had better mood, and depressed patients experienced improvements in their symptoms.
This suggests that the connection between the amygdala and ACC is important for regulating mood in both healthy people and those with depression.
It also suggests that developing treatments that enhance this connection could be a fast way to help people with depression.
Sleep deprivation and cortisol spikes
Dr. Atif Zafar, board certified in stroke and vascular neurology at St. Michael’s Hospital, Unity Health Toronto, who was not involved in this research, spoke to Medical News Today, saying, “as a neurologist, I am interested to see more research come out in this area to build on this work.”
Dr. Zafar pointed to a previous study suggesting that amygdala-ACC connectivity may have implications for mood disorders such as anxiety and depression.
Based on this paper and other previous publications, there is also “an association between cortisol levels impacting this amygdala-ACC pathway,” Dr. Zafar explained.
“I [t]hink that some of these patients in the PNAS study, with a diagnosis of depression, had cortisol level changes when faced with sleep deprivation. It is well known that sleep deprivation leads to an increase in body stress which in turn leads to rising blood levels of cortisol. Is it possible that, directly or indirectly, these cortisol levels may have enhanced the connectivity depicted by fMRI? Or other similar confounding factors may have played a role in the fMRI findings reported in this study.”
— Dr. Atif Zafar
Short-term sleep deprivation may help depression
James Giordano, Ph.D., Pellegrino Center professor of neurology and biochemistry at Georgetown University Medical Center, who was also not involved in the research, told MNT that “the notion that short-term sleep deprivation could improve clinical signs and subjective symptoms of depression has been known for a while, as supported by both anecdotal evidence and a number of research investigations.”
“However, putative mechanisms underlying the observed beneficial effects have remained generally unknown,” Dr. Giordano explained.
“The role of the anterior cingulate cortex (ACC) in depression has been documented previously, and serves as a viable therapeutic target, in light of its connectivity to nodes and networks of the brain that appear to be involved in emotional stability, regulation, and mood,” he added.
“This is the first study to demonstrate —using state-of-the-art neural imaging— that one-night total sleep deprivation induces changes in functional connectivity between the anterior cingulate cortex and regions of the amygdala, a brain region known to contribute to levels of cognitive, emotional, and behavioral arousal, motivation, and overall affect.”
— Dr. James Giordano
Potential implications for depression treatment
“What I am excited about is the potential of amygdala-ACC connectivity being an area of future research in mood disorders,” Dr. Zafar highlighted.
“There is potential for targeted therapy that may be useful in finding cures in a small subset of people with mood disorders,” Zafar said.
Dr. Giordano agreed, saying the research “further supports the role of neuroimaging in identifying key processes of mental health and illness that may be viable for therapeutic targeting, utilizing both low-tech and high-tech means.”
“The implications of this study are multi-fold,” Dr. Giordano highlighted.
“First, is that it demonstrates a potential mechanism for sleep deprivation-induced alleviation of depressive symptoms,” he said.
“Second, is that it supports this behavioral intervention (one-night total sleep deprivation) as useful either as a primary or supplemental intervention, both in depressed patients, and to afford positive mood regulatory effects in healthy individuals,” he continued.
“Third, is that these findings reveal the benefits of utilizing combinatory high-tech approaches to assess and identify the potential value of low-tech interventions that can be used both therapeutically and for health promotional purposes,” Dr. Giordano further explained.
“Of course, it is important for patients and the public to recognize that these protocols were conducted under rigorous clinical supervision, and individuals should consult with their healthcare practitioners before attempting any behavioral intervention, inclusive of sleep deprivation.”
— Dr. James Giordano
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