22/12/2023
Continued from Part 1. The basal forebrain is involved in sleep-wake homeostasis and the production of adenosine which contributes to ones desire to fall asleep. Caffeine blocks adenosine receptors - the receivers waiting for the "get sleepy" message to be effectively received. Therefore caffeine can reduce your sleep urgency or sleep drive.
Finally, the amygdala - which plays an important role in regulating critical emotions such as fear - becomes more active during REM sleep and is partly responsible for the different emotions you feel during your dreams.
Clearly, there’s a few things going on in the brain when it comes to sleep onset and maintenance. What about sleep stages?
There are four stages to one sleep cycle: NonRem1 (NREM1), NREM 2, NREM3 (Deep sleep) and REM. REM (Rapid Eye Movement) is when your brain is most active when you sleep, and is generally when the majority of your dreams occur.
We need 4 to 6 sleep cycles each night to feel adequately rested. Any less than 3 and most people will experience some daytime sleepiness. 2 or less and you’re in for a bad day.
