Over our lifetime our brain changes with our body and our life experiences. Neuroscientists have discovered changes in the synaptic density of human brains that have had more life experiences and more education. These discoveries disproves the myths that the more synapses a person has the more intelligent they are, that synapse formation is only processed during early development and is the saved until needed, and that early environmental stimulation causes a increase in synaptic density.
 

Introduction

       In 1989 President George Bush signed a resolution declaring the 90’s the Decade of the Brain. Neuroscientists have lived up to the bill. In the 90s scientist found genes that link to mental illnesses, they have located different regions of the brain and are now able to tell what their functions are, among many other things. As we move into the 21st centaury neuroscientist are still making new discoveries. One thing that hasn’t changed is the fact that people are born with all the neurons they will ever have. “Neurons come in different shapes and forms, but they all have a cell body that contain the cell nucleus” (Bruer 266). When the cell body dies it can be replaced. The connections between neurons are called synapses, and these neurons never actually touch, this small gap is called the synaptic cleft. Neurons communicate across these gaps, which starts to form two months before birth and continues through the first year of life. Although some people believe that the more synapses a person has the more intelligent they are. This is one of the many myths people believe. Some people try all types of techniques and process to increase synaptic density. Synaptic density continues to change throughout adulthood. Therefore these technique people believe are completely untrue and will never work. 
 
        Counting synapses in the human brain is almost impossible or as John Breur states it, it is “ the scientific equivalent of estimating the number of needles in a haystack, when both the number of needles and the size of the haystack are changing at constantly different rates” Peter Huttenlocher and his colleagues at the University of Chicago discovered that a increase proceeded by a decrease in synaptic density occurs because of synapse elimination in the brain and not because the brain grew as the number of synapse remained unchanged. Also in 1979, Huttenlocher released results showing a change in synaptic density over the life of a human brain. He discovered a rapid increase in synaptic density between birth and 1 year. Around one to two years their synaptic density was 50% higher than an average adult. Between 2 and 16 years synaptic density declined to a certain level and remained there throughout adulthood. Huttenlocher suggested that the decline in synaptic density could not be determined by a single number of synapse in the brain. Although at age seven the human brain has reached adult capacity, the synaptic density is 36% higher than in adults. Therefore the decrease in synaptic density is due to a loss of synapses during development. In 1982 Huttenlocher reported changes in synaptic densities in the visual cortex. Synaptic densities in this area of the brain were still nears adult levels. There was a longer gap in the time of decreasing density, which existed beyond three years and becomes constant at adult levels around age 11. (247-252)

The Myths of Synapses Formation
        
         There are three myths that glorify synaptic density, which is the amount of synapse in the brain. These myths give people the idea that it is important to have a high synaptic density. The first of these myths is that the more synapses a person has the more intelligent they are. This process suggests activities to increase synapses in humans. Some of the suggestions are that we educate ourselves because the more education you have the more synapses you have. Others are meet new and different kinds of people who can stimulate your mind and teach you things, explore all aspects of things and keep an open mind.  Also has children go through puberty and become teenagers; parents may see more changes and problems occur in their children academically and socially. These teenagers are at a stage where they are learning new things that are more complex where synaptic elimination occurs. Therefore these children are not becoming unintelligent; they are losing synapses before they reach adulthood.  
 
      Huttenlocher has found some instances where children with mental disabilities have higher synaptic densities, then those with out disabilities. Although it is during the time when no or little synapse formation occurs that people learn the most, some neuroscientist believe there is a relationship between brain connections and intellect, but there is not enough information at this time to determine what that relationship is, until then there is not enough evidence to support the myth that the more connections you have the smarter you are.

     The second myth is the belief that early development in babies is crucial because that is when synapses are formed. This myth suggests we talk, sing, and read to babies to stimulate their brains. An ad that feeds into this is for a Baby Dazzler Video. This is a video with “striking colorful computer animations” set to classical music that “ can help increase a baby’s learning potential by increasing the number of connections (synapses) in the brain.” This ad appeals to new parents who want their children to be the best, which includes being intelligent.  Scientific research shows that in some cases genetics not environmental surroundings control synapse formation.

    Test have been preformed to show that although animals have different life spans from humans there are some similarities in early development. Rapid synapse formation begins in the visual cortex   of rats about two days after birth and they continue to increases until rats are about two weeks old. Synapse formation begins before animals adapt to their surrounding or have stimulation from their surrounding. This shows that environmental influence is not necessarily a cause of an increase in synaptic density. This compares to humans because humans develop synapses before birth with no contact or idea of what their developmental environment will be.

     In another experiment done by Mary Carlson, a baby monkey’s right hand was restrained with a leather glove. The monkey’s hand remained restrained from birth until it was over 4 months old. During the time of the monkey’s restraint its right hand received no stimulation. Carlson thought that the restraints and lack of stimulation would prohibit the monkey’s ability to make distinctions in sizes and texture in objects. When Carlson removed the mitten, the monkey performed as well as other animals. During the four months the right hand was not in use it didn’t receive any stimulation from the particular part of the brain that processes this stimulation. Therefore this part of the brain didn’t function, which shows the brain doesn’t have to have stimulation during early development in order for synapses to form. In this case synapse formed in the absence of any stimulation. (Carlson 69-89)  As said by Goldman-Rakic, Bourgeois, and Rakic “The developmental accumulation of synapses is altered much less by environmental stimulation than has been appreciated or would be expected by conventional wisdom”(pg.38)

         The third myth is that during the time synapse form, when we learn basic skills and after this process ends synapse formation ends. A study was done by Goldman-Rakic and developmental psychologist named Adele Diamond, which showed how memory skills develop in the early months of infant monkeys and infant humans. In the experiments the subject would watch someone hide an object in one of two holes, then take the subject away from the holes for a period of time. After a certain time, the subject returns and selects one of the two holes. The experiment requires that the baby or monkeys remember where the object was hidden for a period of time and then find the object with no help and the only thing they have to rely on would be there memory. (24-40)
 

      This task may seem simple but it uses very important mental skills. According to Dr.Goldman-Rakic the representative memory is “a building block, if not a cornerstone, of cognitive development in man.” (604) The factor of this experiment is the length of time the animal or infant can be away without making a wrong choice. In the monkeys by the age of 2 months they could only tolerate an away time of 5 seconds, and by the age of 4 months they could tolerate away time of up to 10 seconds. The human infants were tested every two weeks from the age of 6 months to 12 months. In the beginning they started to succeed at times of up to 2 seconds around seven months. By the age of one they could tolerate delays of up to 10 seconds. This shows that monkeys’ memory abilities between 2 and 4 moths occur at 7 to 12 months in human infants.

      Diamond and Goldman-Rakic also tested if experience contributes to memory skills. They tested a second set of human infants. This set they tested only once instead of bi-weekly. This set ranged from age 2 months to 12 months. They found no difference in the performance, that of the infants who had done the test bi-weekly. On these same test Adults were able to go hours if not days. The skills we need to do this are not permanently fixed during birth or in early development. Nor is it limited to the time when synapses are forming. We know this because we learn new things each day and we don’t forget them the next. (24-40)

     These myths are just that myths. Synaptic density doesn’t affect our intelligence level in the way that we may think. More doesn’t necessarily mean better, nor is intelligence only determined in early development. The brain is a very complicated machine. Although synaptic density doesn’t measure intelligence, recent research shows that some highly educated people in certain professions have a high synaptic density.

Professions and Synaptic Density
 
      Research has shown that stimulation doing early development doesn’t increase synaptic density, nor is intelligence measured by a person’s synaptic density. Although a recent release from University of Illinois Beckman Institute for Advanced Science and Technology says that people in certain Professions have more synapses.
 
         “Education not only makes a person smarter, it may generate a specific type of synapses in the prefrontal cortex of the brain,” say Russian neuroscientists. James Black, who is part of a team examining brain tissue at the University of Illinois Beckman Institute for Advanced Science and Technology, says there were more synapses in people who are in certain professions, such as engineering or teaching. In this study Black used an electron microscope that allowed his team to count neurons and synapses in 16 people. They did interviews with each subject asking about occupation, and daily activity. They also examined upper layers of the visual cortex. The results showed that subjects with more professional training had 17 percent more synapses then their less educated counterparts. Synapses formation is suppose to be a way to store information that is obtained through experience. “Experience can drive the formation of new synapses,” said Black. This research show that the education and experience people receive throughout life can increase their synaptic density. Therefore people’s synaptic density will always be changing. People learn something-new everyday and go through different experiences each day. Someone may have a high synaptic density today and a lower one tomorrow. “Some you use, Some you lose.”(Bruer 264) Synaptic elimination occurs at purity and continues throughout life. 

        The cause or the amount of synapses as gone without being determined and may go a few more. As long as there are neuroscientist who are studying the brain and finding different, new, exciting, discoveries there will always be a different answer to this question. There are hundreds of pages of research, there are many myths and hypothesis about why humans do the thing they do and react to certain stimuli. The brain is a creation that no two are alike, each one has its own unique characteristics, and each one is special in its own way. The myths of synaptic density will continue to be believed by people, because in today’s society people believe more is better than less.