Placeholder Image

Subtitles section Play video

  • So exactly, how does a lack of sleep impact our emotional brain?

  • Why does that lack of sleep make us so emotionally irrational and hyper-reactive?

  • Well, several years ago, we conducted a brain imaging study.

  • And we took a group of healthy adults.

  • And we either gave them a full night of sleep or we sleep-deprived them.

  • And then the next day, we placed them inside an MRI scanner, and we looked at how their emotional brain was reacting.

  • And we focused on one structure in particular, it's called the amygdala.

  • And the amygdala is one of the centerpiece regions for the generation of strong emotional reactions, including negative emotional reactions.

  • Now when we looked at those people who had a full night of sleep, what we saw was a nice, appropriate, moderate degree of reactivity from the amygdala.

  • It wasn't as though there was no response at all, but it was an appropriate response.

  • Yet in those people who were sleep-deprived, that deep emotional brain center was in fact, hyperactive.

  • Indeed, the amygdala was almost 60 percent more responsive under conditions of a lack of sleep.

  • But why was that the case?

  • And what we went on to discover, is that there's another brain region that's involved.

  • This brain region is called the prefrontal cortex, and it sits directly above your eyes.

  • And you can think of the prefrontal cortex almost like the CEO of your brain.

  • It's very good at making high-level, executive, top-down control decisions and reactions.

  • In fact, it's one of the most evolved regions of our brain.

  • And one of the parts of the brain that it controls is this deep emotional center, the amygdala.

  • Now in those people who had a full night of sleep, there was a nice, strong communication and connection between the prefrontal cortex, regulating that deep emotional brain center.

  • But in those people who were sleep-deprived, that communication, that connection between the prefrontal cortex and that deep amygdala emotional brain center had essentially been severed.

  • And as a consequence, the amygdala was responding far more reactively due to a lack of sleep.

  • It's almost as though without sleep we become all emotional accelerator pedal, and too little regulatory control brake.

  • And that seems to be the reason that we become so unbuckled in terms of our emotional integrity when we haven't been sleeping well.

  • So that's the bad that can happen if I take sleep away from you.

  • But it turns out that there's something good that happens when you get your sleep back.

  • And sleep, particularly rapid eye movement sleep, actually offers a form of emotional first aid.

  • Because it's during sleep at night that we take these difficult emotional experiences that we've been having during the day,

  • and that sleep acts almost like a nocturnal soothing balm, taking the sharp edges off those difficult experiences.

  • And so perhaps it's not time that heals all wounds, it's time during sleep that provides that form of emotional convalescence.

  • So that when we come back the next day, we're able to cope with those emotional memories.

So exactly, how does a lack of sleep impact our emotional brain?

Subtitles and vocabulary

Click the word to look it up Click the word to find further inforamtion about it