Most of the time we are in control of our moods, rather than our moods being in control of us. One of the main things that we learn as we get older is not simply to damp down our emotional reactions, but to make them “contextually relevant:” we produce the right emotional response for the right situation. Yet we also know that there are exceptions: times when our emotions over-run any attempts at our control.
Second, we all know that sleep deprivation can be a Bad Thing. It is known to impair a range of mental and physical activities, including immune function, metabolic control and many cognitive processes, including learning and memory.
It has long been suspected that sleep deprivation can have significant effect on mood. Many of us feel irritable and distractible if we haven’t slept enough, and you may have had the experience of being up all night and feeling a little bit “high” in the morning. It has also been known for centuries that mood disorders are very commonly associated with sleep disturbances, and sleep disturbance is often the first sign that someone with mood problems is running into trouble. So mood and sleep must be linked in some way.
Despite these common observations, there has never been that much empirical evidence for the impact of sleep deprivation on mood, and in particular the effects of sleep deprivation on the brain.
An important new study by researchers from Harvard Medical School and the University of California at Berkeley has just been published in the journal Current Biology, and it is beginning to fill in some of the gaps in our knowledge.
The amygdala is known to be involved in processing of emotionally salient information, particularly unpleasant or aversive stimuli. In mature individuals, the emotional centers of the brain are usually controlled and modulated by an array of connected systems, mainly in the frontal regions of the brain. One particularly important part of the frontal lobes that is involved in controlling the amygdala is the medial-prefrontal cortex (MPFC). Under normal conditions the MPFC is supposed to exert an inhibitory, top-down control of the amygdala, so that we only generate appropriate emotional responses.
The scientists worked with 35 volunteers who were deprived of sleep for 35 hours. Blood flow can be used to deduce which specific regions of the brain are active. The researchers used functional magnetic resonance imaging (fMRI) to examine the blood flow – and therefore activity - in the brains of the volunteers in real time, both during and after sleep deprivation.
After going without sleep, the participants were asked to look at images that were designed to trigger angry or sad emotional responses. The investigators discovered that the amygdala showed 60% higher reactions to the images compared with people who are not sleep-deprived.
This is an extraordinarily large effect and implies that sleep deprivation knocks out the normal control mechanisms in the frontal lobes so that the sleep-deprived brain reverts to a more primitive pattern of activity. As a result we become unable to put emotional experiences into context and produce controlled, appropriate responses.
If we needed any more reasons to get a good night’s sleep, this one is very powerful. It also re-iterates something very important: if you or a loved one have had problems with mood, anger or anxiety, it is essential to watch your sleep pattern. Any change may be a harbinger or trouble, and is an excellent early warning that you or they need a hand to make sure that things stay on an even keel.
"Your brain shall be your servant instead of your master, you will rule it instead of allowing it to rule you.”
--Charles E. Popplestone (American Author of Every Man a Winner, 1936)
“Control your emotions or they will control you”
--Chinese Proverb
“For the uncontrolled there is no wisdom, nor for the uncontrolled is there the power of concentration; and for him without concentration there is no peace. And for the unpeaceful, how can there be happiness?”
--Bhagavad Gita (Ancient and Sacred Sanskrit Poem Incorporated into the Mahabharata)
“He who controls others may be powerful, but he who has mastered himself is mightier still.”
--Lao Tzu (Obscure Chinese Philosopher, Founder of Taoism and Alleged Author of the Tao-Te Ching, c. 604-c. 531 B.C.E.)
“ . . . let every man be swift to hear, slow to speak, slow to wrath.”
--The Bible, James 1:19
“When angry, count ten before you speak; if very angry, a hundred.”
--Thomas Jefferson (American Writer, Philosopher, Politician and, from 1801-1809, 3rd President of the United States, 1743-1826)
