WHAT HAPPENS WHEN YOUR BRAIN DOESN'T SLEEP?
The hippocampus, a rnoon-shaped structure in the ternporal lobe, exhibits a distinct pattern of neural activity when the waking mind encodes (learns) new information. Scientists believe our brain later "replays" the sarne activity pattern while we're sleeping to help the info stick. Lose sleep, lose long-term memories.
Sleep loss primes us to focus on negative experiences, misinterpret facial expressions and pick fights. Emotional volatility may partly be a product of interrupted communication between brain regions. FMRI of the well-rested brain shows connectivity between the amygdala, a limbic system structure critical to emotional processing, and the medial prefrontal cortex, which helps regulate feelings (i.e., tells us to chill). Sleep deprivation cuts this connection, letting your revved-up arnygdala (and your mood) run wild.
When you skimp on sleep, the clever commentary rnay not flow so easily. Sleep loss affects cognitive processes like divergent thinking, which helps us switch topics nimbly during conversation. Scientists found that activity in theinferior frontal gyus increases when sleep-deprived people tried to list uses for different objects, suggesting the brain draws on divergent thinking to compensate for strained cognitive functioning.
The well-rested brain filters stimuli (noise, light, smell, etc.) to separate what matters from what doesn't and prevent sensory overload. When the brain can't filter the information corning in, chaos ensues. After pulling an all-nighter, people may begin to anticipate things that aren't there, including objects.
HEAD IN THE CLOUDS
We all lose focus now and then, but brain activity linked to attention lapses changes when people sacrifice sleep. After a good night's rest, these lapses correspond to altered thalamus function and less-active frontal and parietal networks, which basically means we tune out when we're bored. But when sleep-deprived people space out, they also exhibit impaired visual sensory processing, suggesting a whole other level of disengagement with the world. In short: Losing sleep turns you into Phoebe from Friends.
The sleep-starved brain may fail to encode memories successfully in the first place, thanks to altered function in the as well as prefrontal cortex and regions. One study found that people are more likely to incorporate misinformation into memories of events observed after a night without sleep.
Healthy adults getting poor sleep lose volume in the and lobes, one study showed. Researchers don't yet understand if sleep loss causes shrinkage or vice versa.
The temporal lobe, the brain region associated with language processing, is highly active in well-rested people but inactive in their exhausted and enunciation-challenged counterparts.
Sleep loss corresponds with decreased activity in the frontal lobe, which controls decision-making, and more activity in the amygdala, a key player in fear detection. Together, these neural changes create a brain mechanism that dulls judgment and ratchets up desire — the ideal mind-state for scarfing down fistfuls of bacon.
When sleep-deprived people prepare to make economic decisions, the brain's reward center in the prefrontal cortex lights up, suggesting they expect to win (e.g., make money). But when risky choices don't pan out, people's brain activity decreases in the region related to punishment and aversion (the anterior insula), suggesting they don't care about losing money as much as they would on a good night's sleep.
Add all-nighters to the list of things that kill brain cells — in this case, in the brain stem. The damage may be irreparable, making "catching up on lost sleep" a poor excuse for snoozing till noon on the weekends.