To Sleep, Perchance To Dream

Dr. William Dement was an early sleep scientist. He set up a sleep lab at Stanford in 1970 and did experiments on sleepers. Building on earlier work on REM (Rapid Eye Movement) sleep by Aserinsky and Kleitmann at the Chicago University sleep labs, Dement showed that dreams occur during REM sleep, and that sleepers have many dreams throughout the night, with later dreams lasting longer than earlier dreams.

Recent experiments with MRI scans of sleeper's brains show that human brains actually reconfigure themselves during REM sleep.

"MRI [magnetic resonance imaging] scans show us that, during sleep, brain regions shift dramatically," notes Matthew Walker, director of the Sleep and Neuroimaging Lab at Beth Israel Deaconess Medical Center. "During sleep, it seems as though you are shifting memory to more efficient storage regions within the brain. Consequently, when you awaken, memory tasks can be performed more quickly and with less stress and anxiety." -- Harvard Gazette

Scientists believe that some of the chemical reactions in the brain that create memory take several minutes or hours to complete. Sleep is a time during which the brain filters out most external stimuli and blocks most motor activity. This may explain why young humans, with much more information to absorb, need more sleep than adults.

Are dreams simply a by-product of memory re-configuration, or do they have symbolic meaning?

Dream research today is torn between two paradigms, said [Allan] Hobson [, M.D., a professor of psychiatry at Harvard Medical School]: the old focus on dreams as interpretable, á la Sigmund Freud, and the new focus on dreaming as a state of consciousness that helps reveal how the brain is organized.

Dement sees neurocognitive research as complementary to psychological exploration, not a replacement for it. In REM sleep, he asserted, the brain creates a world all by itself. "You can see, hear, smell; you perceive the world around you to be real.

"Although dreams mirror concerns from the day, they are never exactly like the day," he said. "But that they are meaningful is obvious." -- Psychiatry Online

Meantime, Hobson and researcher Mark Solms are debating what parts of the brain are involved in waking and sleeping. Hobson believes that dreams are linked to the parts of the brain that control the REM cycle, while Solms thinks parts of the higher brain start dreams.

In Solms theory, dreaming begins in the higher brain when a particular area of the forebrain is activated, the mediobasal frontal cortex. Here the hunting, seeking, desiring, wanting system is deeply networked with the limbic system (emotions, sensory info) and mesocortical dopamine systems. There are deep connections of dopanminergic cells from this ventral tegmental area to the hypothalamus, the septal area, the cingulated gyrus and the frontal cortex, and amygdala. In other words, this frontal cortex area of motivation connects with many other parts of the higher brain, the sensory brain and the emotional brain. -- Improverse.com

Early researchers like Dement measured dream activity with cameras, EEGs, and patient interviews. Current researchers have added PET and MRI scanners to their measurement arsenal so they can see what happens inside the brain.

To put you, dear reader, to sleep so your memory can reconfigure this article into your brain, here is a gratuitous MRI scan of a brain.



If you're wondering whether you have a sleep disorder, you can take this test. A good night's sleep may be more important than you realize.