Does smoking marijuana kill brain cells?
Everyone knows long-term alcohol use kills brain cells, but what about marijuana? The short answer is no. Technically, continued use affects the receptors in the brain cells but does not decrease the actual number of them. These receptors can be dulled over time, causing an increase in marijuana use that leads to tolerance. Tolerance means that more marijuana is needed to produce the same effects. Marijuana also has a proven effect on short term memory that happens through a process of internalization to the N-methyl-D-aspartate receptor of NMDA. This is a complicated way of saying that this receptor, which helps the flow of short term memory, retreats into the brain after coming in contact with marijuana receptors. This makes the receptor not as accessible, causing you to forget short term events. Overall, occasional use of marijuana has minimal proven negative effects and some benefits. Constant and heavy use can lead to tolerance, brain fog and other complications — but not dead brain cells.
Why is yawning so contagious?
To be quite honest, we don’t really know. Some scientists think that the contagious effects are because of our mirror neurons, which are a special type of neuron in the brain that helps us mimic the behavior of others. This mirror-neuron theory states that when someone yawns, our mirror neurons start firing, causing us to mimic the act of yawning. This effect can be so strong that even other animals can catch the yawn contagion. Mirror neurons are thought to be important for the process of learning new skills, as well as the basis for the development of empathy in humans. Still, no one has found a strong link as to why yawning happens in the first place; the theories range from tiredness, boredom, brain temperature regulation or even a way to maintain the “herd mentality” by bringing everyone to the same mood through yawning.