 |
 |
 |
|
 |
|
 |
 |
| Illustrations by Rod Clement |
|
|
LITTLE KNOWN FACTS ABOUT THE BRAIN
By Dr. Stephen JuanDOES THE BRAIN EVER SLEEP?
No. The brain never stops working and so never sleeps. Does it ever rest? When you lose consciousness and enter the deepest part of the sleep cycle, your brain stops communicating with some of the other parts of itself. According to researchers at the University of Wisconsin at Madison, the “awake” brain functions as chemicals and nerve cells “chatter” continually. Yet in the deepest part of sleep, all those cerebral parts break down into little islands that cannot communicate with one another. The researchers used a non-invasive technique called trans-cranial magnetic stimulation to activate certain parts of the brains of a group of volunteer subjects. Electrodes were attached to each subject’s head to monitor how the stimulation triggered reactions in other parts of the brain and body. When the subjects were dreaming in the early morning hours, brain signals were almost as active as when they were awake. But during deeper sleep, the brain was quiet. The head of the research team, Dr. Giulio Tononiui of the Psychiatric Institute and Clinics at the University of Wisconsin says that “during deep sleep early in the night, the response is short-lived and doesn’t propagate at all. The brain is compartmentalizing to allow the synapses---those areas in the brain that let us think---to take a break and rest. This process would allow cortical circuits to eliminate noisy synapses and renormalize in order to be ready for the next day. This process may also explain the well-known phenomenon of improved performance and learning after sleep. Conscious thought depends on the ability of the brain to integrate information. This study helps verify that belief”.* * *
ARE PRIMITIVE BEHAVIOURS HARD-WIRED IN THE HUMAN BRAIN?
Often so-called primitive behaviours were probably hard-wired in the brain. For quite some time scientists have observed that behaviours of lower organisms are very often innate. Ants instinctively follow other ants to a picnic basket. Birds fly largely on autopilot. However, in non-human primates as well as in humans, behaviour is believed to be largely something that is learned rather than innate. But if that is so, why do many reactions, such as aggression, play out the same way among diverse populations around the world? Vanderbilt University scientists recently attempted to answer this question. The researchers succeeded in triggering complex behaviours in a small primate called the bush baby by stimulating specific areas of the brain. The triggered behaviours included aggressive facial gestures, defensive arm movements, putting hand to mouth, and other reaching and grasping movements---all survival skills. Earlier studies had brought out the same behaviours in other primate species. According to Dr. Jon Kass, head of the Vanderbilt team, “We have now seen this feature in the brains of Old World primates and the brains of New World primates. The fact that it appears in the brains of two such divergent primates suggests that this form of organization evolved very early in the development of primates. That, in turn, suggests that it is characteristic of all primate brains, including the human brain. These results explain why certain behaviours such as defensive and aggressive movements, smiling and grasping food are so similar around the world. It is because the instructions for these movements are built into the brain.”* * *
IS IT EASY TO MAKE PEOPLE REMEMBER THINGS THAT NEVER HAPPENED?
Scientists have discovered that it is easy to make people remember things that never actually happened. It has long been known by scientists that the parts of the brain that form, store, and retrieve memories must all work together to accurately recall events. Since much can go wrong with this complicated process, scientists have long been sceptical of the accuracy of human memory. Researchers at Northwestern University decided to design an experiment to bring people into the laboratory and set up a circumstance in which they would remember something that did not happen. Under the direction of psychologist Dr. Kenneth Paller, researchers monitored the brains of subjects with functional magnetic resonance imaging (fMRI) to track the false memories. The researchers showed subjects pictures and asked them to imagine other images. Later, investigators asked whether certain objects were seen or imagined. Often, imagined images were recalled as real. According to Dr. Paller, “We think parts of the brain used to actually perceive an object and to imagine an object overlap. Thus, a vividly imagined event can leave a memory trace in the brain that’s very similar to that of an experienced event. When memories are stored for perceived or imagined objects, some of the same brain areas are involved.” In a study published in the October 2004 issue of Psychological Science, the Paller team provided evidence that certain parts of the brain are involved in forming false memories and different parts of the brain were responsible for creating true memories. The key to remember that something was imagined when we recall it is the context surrounding a memory. If you remember who told you to imagine something, where it was, what was going on around, and so on the separation between what really happened and what you imagined becomes more distinct. When a person makes these external connections to the memory, they engage the parts of the brain that lead to true memories. According to Dr. Paller, “False memories are only one part of studying how memory occurs. We are excited about the prospects of connecting what we have learned in the laboratory to the real world. What we learn could be useful for people who make decisions outside of the lab based on the memory of others.”* * *
The going rate for a human brain is about $US1500 when a brain is sold to laboratories for research purposes.
Home | About Stephen | Odd Books | Odd News | Odd Quiz | Contact
Copyright HarperCollins Publishers 2002 | Privacy Policy | Terms of Use