Biology 202

2006 First Web Paper

On Serendip

Many people still believe that autistic children are the equivalent of a normal child trapped within a glass shell (3). The information that is open to the masses is vague and minimal. It is described as a flaw in the ability to communicate and interact socially. Causes of autism often point simply to structural abnormalities in the brain (1). There is a general focus that each child is an individual, with a variety and symptoms and expressions of symptoms (1) (4). The reasons and theories about the causes of autism and relationship between symptoms are missing.

The mind of an autistic child is very different from that of a normal child. It is defined by four common behaviors: a desire for sameness, a preference for aloneness, a desire to follow complex routines, and abilities that seem exceptional compared with deficits (3). Autism does not always include mental retardation, although this is common (3) (6). The behaviors expressed often have to do with problems in communication, socialization and imagination (3).

Autistics may have trouble with second order representation, which involves imagination and integration of ideas leading to problems in communication, socialization and imagination (3). . They know the visible events of the world but cannot understand metaphoric or incongruous information (3). They see many details but cannot form full picture or concept (4) (6) (8). While they may be able to perform complex tasks their understanding of what is happening is minimal; for example they may memorize 7000 novels, but cannot understand them (4) (7). They take everything in the literal sense (3) (4) (7). Conversation is often full of facts and rarely interactive (4). They may also lack theory of mind, which is the ability to understand the mental state or intention of another (3) (6). High functioning autistics can learn social routines, camouflaging their disorder, because social skills that do not involve an exchange between minds can be learned (3). .

The biology of autism is not well understood. It may be controlled by up to 20 genes, where autistics can carry only some of the genes, and the genes can remain silent in others (5) (6). Even in identical twins, if one has the autism there is only a 60% chance of the twin also expressing it (5). Different autistics express different genes (6). This results in possible structural variations between individuals.

Chemical agents can cause damage to the brain resulting in autism. Thalidomide babies showed higher than normal rates of autism. Further studies and comparison with other related developmental problems showed evidence that the brain damage that causes autism occurs early in pregnancy, when the brain is first forming (5). It has been suggested testosterone early in development damages the left brain of male babies and accounts for the higher rates of autism in males than females (5). Oxytocin, a hormone which regulates social behavior in mammals through receptors in the brain, is present in lower levels in autistics. When levels are increased, repetitive behaviors decreased (6).
Autistics receive information from the outside world as well as normal children, as demonstrated by the abilities of some to create flawless renderings of their surroundings (7). What they cannot do is integrate and understand the input (3). Therefore, it can be concluded that it is a problem in the brain's interpretation of the input and not the input that is altered.

Evidence points to both disconnections in the brain and deformities in different regions as causing the symptoms. MRI's during questioning sessions make it appear as though some areas of the brain are disconnected href="#8">(8) (7). It is speculated that the long fiber tracts that connect mirror neurons are less organized in autistics altering the way that information is integrated href="#8">(8). They also have a greater amount of white matter, especially in the frontal regions where information integration occurs href="#5">(5) href="#8">(8). It is suggested by the pattern of white matter that brain regions like the prefrontal cortex may have hyper-efficient internal processing but may have poor connections to those of other areas href="#8">(8). This may be the reason autistics show incredible talents in only a few areas. Frontal regions active in understanding other's intent tend to be less active in autistics. The visual region as well was out of synch with the mental-strategy network, which may be the reason autistics have trouble with motor function href="#8">(8).

The prevalence of savant-like abilities in autistics suggests that there are problems in communication with the left hemisphere of the brain for which the right compensates. Autistics comprise half of all savants (7). These individuals can perform activities that are functions of the right brain, such as math, art, and memorization but the understanding and creativity of the left brain are lost. This has been shown in brain scans that there is often damage to the left hemisphere. It has also been shown that the right hemisphere can be hyperactive (7).

Both the amygdala, which controls emotion, and the hippocampus, which is responsible for learning and memory, are decreased in size. They both have fewer connections to other regions of the brain, possibly leading to the inability to interpret emotions and understand concepts (6). When viewing faces, the amygdala becomes over stimulated leading to the aversion of eye to eye gaze (2). Cerebellums often show deficiencies in Purkinje cells, which are important in brain circuitry leading to further disconnection (6). The brain stem just above the spinal chord is shorter with the pons and medulla closer to the lower medulla, as though a piece is missing (3). The pons is important in the relay of sensory information between the cerebrum and cerebellum. The medulla relays information between the brain and spinal chord (3). These deficiencies further point to a disconnected brain at the root of the disorder.

There is an abundance of evidence suggesting that autism is linked to malfunctions in areas of the brains but mostly in the communication of one brain region to another. These malfunctions change the way input is integrated and trap the autistic in a world they cannot interpret. Functions of understanding and communication become very difficult. While autism has a genetic link, it seems that environment plays a huge role in the expression of the genes. While there is still a lot that is unknown, the best available information is published in online journals and not on the web.

1) Autism Society of America1) Autism Society of America. Accessed 20 Feb 2006.
WWW: http://www.autism-society.org/site/PageServer?pagename=autismcauses
2) Beard J. New View on Autism. Scientific American Mind. 2005
3) Frith U. Autism. Scientific American ©1997 reprinted from June 1993 issue
1) National Institute on deafness and other communication disorders 4) National Institute on Deafness and other Communication Disorders. Autism and Communication. NIH Pub No 99-4315. Oct 1998. Updated Jan 2003. Accessed 20 Feb 2006
WWW: http://www.nidcd.nih.gov/health/voice/autism.asp?AddInterest=1053#4
5) Rodier P. The Early Origins of Autism. Scientific American. Feb 2000
6) Stokstad E. New Hints into the Biological Basis of Autism. Science Magazine. 5 Oct 2001. Vol 294 no.5540. pp 33-37
7) Treffert D, Wallace G. Islands of Genius. Scientific American Mind. 2003
8) Wickelgren I. Autistic Brains Out of Synch? Science Magazine. Vol 308 no 5730


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