Rabu, 27 November 2013

What are dreams? Psychology, neuroscience try to explain them

What are dreams? Psychology, neuroscience try to explain them

What are dreams, exactly?
One explanation that was highly influential in the first half of the 20th century was put forward by Sigmund Freud and other psychologists. In Freud's “The Interpretation of Dreams,” published in 1900, he asserted that dreams are the manifestations of urges and desires that we keep suppressed in the realm of our subconscious, and the practice of dream analysis based on this theory subsequently gained popularity.

According to Freud, our subconscious desires include those that we don't want to admit, such as sexual urges. For that reason, tools, rooms, and other objects, and behaviors including flying, appear symbolically in our dreams. It is thought that if we can unravel the correspondent relationship these symbols have with issues in our waking lives, we can understand these subconscious desires.

While Swiss psychologist Carl Jung criticized Freud's theory as being too preoccupied with sexual desires, he systematized the theory stating that dreams are messages from our subconscious. Jungian dream analysis is still used widely today in psychoanalysis and psychotherapy.

In contrast, in the latter half of the 20th century, a movement emerged in psychology that took a different approach to dreams: research from the perspective of neurophysiology, which tries to decode activity in our brain and nervous system.

Harvard Medical School professor emeritus Allan Hobson, 79, has long been regarded as one of the front-runners in this field. When I visited him at the massive farm where he lives in the state of Vermont, he declared that he is “the first person to ever study dreams scientifically.” In his view, the theories of Freud and Jung have no scientific basis.

At the beginning of the 1960s, Hobson worked as a resident in the psychiatric ward of a hospital in Boston. This was a time when Freudian psychoanalysis was all the rage. However, Hobson began to harbor serious doubts regarding the practice of psychology and its disinterest in the actual workings of the brain.

Let's focus on the workings of the brain, instead of probing the content of dreams--using this approach, Hobson pursued his own research and put forward a new theory in the 1970s.

It asserts that when we enter REM sleep, the state in which we dream the most, a signal is sent out from the brain stem located farthest below the brain, and the area of it responsible for visual perception becomes active. During sleep, we cease to input information from the outside world, so the brain takes memory fragments and pieces them together to create a story: a dream. The part of the brain that handles caution and judgment is not fully active at this time, which results in incoherent stories.

Hobson says that this is why our dreams have no "meaning" that we can decipher. He himself often has dreams in which he is on a farm.

“I own the farm, so of course, I’m worried about it. I don’t think that’s true that I have some sort of deep symbolic drive. I think that can be misleading.”

Hobson's theory has been an established facet of neurophysiology for many years. However, in the latter half of the 1990s, University of Cape Town professor Mark Solms, 64, presented a new theory. It included aspects that could be described as a rehabilitation of Freudian thinking.

Solms has an older brother who suffered a brain injury in an accident. This was part of the reason that he began this line of research. At first he believed in Hobson's theory, but as he carried out studies of people with brain injuries, he realized that some continued to have dreams despite sustaining damage to their brain stem, which Hobson posited as the switch that activated dreams. In contrast, he discovered that people cease to have dreams when the frontal part of the brain controlling urges is damaged.

Solms theorized that dreams originate with the urge to do something, which is expressed using information stored in the brain. In other words, dreams are manifestations of urges, meaning that Freud's theory was not incorrect.

Hobson and Solms have subsequently continued to argue over this issue, and their conflict has taken on a strong "pro-Freud versus anti-Freud" quality.

University of Wisconsin-Madison professor Giulio Tononi, 51, a neuroscientist who has gained attention for his research into defining consciousness, has followed Hobson and Solms' dispute with interest. In his understanding, Hobson's theory views dreams as an activity close to a sensory perception in response to some form of stimulation. On the other hand, Solms' definition of dreams as manifestations of urges sees them as an activity akin to closing your eyes and picturing something, which is to say that they are closely related to our imagination. Tononi believes that Hobson and Solms' tug of war between sensory perception and imagination is worthwhile, but regards its overemphasis on Freud as unproductive.

Now that things have come this far, it seems that they are approaching some kind of common ground. In a recent thesis, Hobson claims that in the middle of REM sleep, “the brain is prepared to activate consciousness right after we awake,” and describes this state as “protoconsciousness.” Dreams are virtual experiences created from visual information stored in the brain that is connected together during protoconsciousness. “When I read it, I thought, ‘This is 90 percent the same as my own theory,' ” says Solms.

Tononi also sees the argument as moving toward an understanding that “dreaming is more closely related to imagination than it is to perception.”

Even so, this does not mean it is possible to analyze the content of dreams, as Freud once asserted. This is because there are major obstacles to scientific research into dream content. We have to rely on a person's verbal testimony as to what they dreamed about, and there are limitations to experimentation with human subjects. Even if we carried out experiments on animals, they could not tell us what they saw in their dreams.

“We are fantastically ignorant about something as basic as the dreaming state of consciousness.”


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