Professor John Pollock’s lecture described how the world was created and evolved. When human was created as a species with learning behaviors, they evolved to create and manipulate tools, languages, and storytelling. The essential role of storytelling is to deliver knowledge, languages, and culture down to the descendant. The knowledge and the living conditions were impacted by day and night before the lightbulb was invented.
Our sleep before the lightbulb was determined by the rise and fall of the sun. If the day gets dark, means time to sleep. If the day is bright, means time to awake. This is because the input of the sensory system creates alert signals from the reticular activating system (RAS) of the reticular formation. When RAS receives sensory input above a normal threshold, it sends norepinephrine and acetylcholine neurotransmitters throughout the brain, it then stimulates the target that it acts on and awakens the whole brain. Then the lightbulb changes our biological clock.
One experiment that Professor Pollock shows is the instinctive reaction of the jellyfish. In the experiment, the awakening jellyfish will fold upon themselves when the shrimp of the tweezer passes through their body(the sensory tentacles, perhaps). They do similar things to the jellyfish when they’re asleep. When the jellyfish is asleep, it’s a bit half-folded, when the tweezer approaches the asleep jellyfish, the jellyfish reacts to the tweezer by folding itself as an action for consuming, thinking or dreaming it’s the food.
Our brain processes the vision we see into the memory and organizes it during sleep. The things that the brain organizes and views could create dreams.
The professor also described the side story about caffeine, how caffeine impacts our sleep by blocking the adenosine receptors, our brain couldn’t receive the message, we’re still awake or energized for some time depending on how much caffeine intake and how each individual’s metabolism deal against the caffeine.