PULSE Magazine | February 2020 Issue

John Morreall, who is a pioneer of humor research at the College of William and Mary, has found that laughter is a playful response to incongruities stories that disobey conventional expectations. Others in the humor field point to laughter as a way of signaling to another person that this action is meant "in fun." One thing is clear: Laughter makes us feel better. Memory Lane Some experiences are hard to forget, like perhaps your first kiss. But how does a person hold onto these personal movies? Using brain-imaging tech- niques, scientists are unraveling the mechanism responsible for creating and storing memories. They are finding that the hippocampus, within the brain's gray matter, could act as a memory box. But this storage area isn't so discriminatory. It turns out that both true and false memories activate similar brain regions. To pull out the real memory, some researchers ask a subject to recall the memory in context, something that's much more difficult when the event didn't actually occur. Mission Control Residing in the hypothalamus of the brain, the suprachiasmatic nucleus, or biological clock, pro- grams the body to follow a 24-hour rhythm. The most evident effect of circadian rhythm is the sleep -wake cycle, but the biological clock also impacts digestion, body temperature, blood pressure, and hormone production. Researchers have found that light intensity can adjust the clock forward or backward by regulating the hormone melatonin. The latest debate is whether or not melatonin supplements could help prevent jet lag — the drowsy, achy feeling you get when "jetting" across time zones Phantom Feelings It's estimated that about 80 percent of amputees experience sensations, including warmth, itching, pressure and pain, coming from the missing limb. People who experience this phenomenon, known as "phantom limb," feel sensations as if the missing limb were part of their bodies. One explanation says that the nerves area where the limb severed create new connections to the spinal cord and continue to send signals to the brain as if the missing limb was still there. Another possibility is that the brain is "hard-wired" to operate as if the body were fully intact — meaning the brain holds a blueprint of the body with all parts attached. Slumber Sleuth Fruit flies do it. Tigers do it. And humans can't seem to get enough of it. No, not that. We're talk- ing about shut-eye, so crucial we spend more than a quarter of our lives at it. Yet the underlying rea- sons for sleep remain as puzzling as a rambling dream.

One thing scientists do know: Sleep is crucial for survival in mammals. Extended sleeplessness can lead to mood swings, hallucination, and in extreme cases, death. There are two states of sleep non- rapid eye movement (NREM), during which the brain exhibits low metabolic activity, and rapid eye movement (REM), during which the brain is very active. Some scientists think NREM sleep gives your body a break, and in turn conserves energy, similar to hibernation. REM sleep could help to organize memories. However, this idea isn't proven, and dreams during REM sleep don't always correlate with memories. Sweet Dreams If you were to ask 10 people what dreams are made of, you'd probably get 10 different answers. That's because scientists are still unraveling this mystery. One possibility: Dreaming exercises brain by stimulating the trafficking of synapses between brain cells. Another theory is that people dream about tasks and emotions that they didn't take care of during the day, and that the process can help solidify thoughts and memories. In general, scientists agree that dreaming happens during your deepest sleep, called Rapid Eye Movement.

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