Synesthesia

After listening to guest speaker David Eagleman talk about Synesthesia during a recent lecture I became extremely curious as to what it would be like to experience this condition. I did some goggling and found an interesting article which explains a little more about this condition. The article can be found here (http://www.lurj.org/article.php/vol2n1/synesthesia.xml).

Synesthesia is a condition in which someone’s bodily senses are associated with completely different senses as well as that particular sense. Such as being not only able to hear sounds but also see the colors of different specific sounds and be able to tell the difference in sounds by the color they see alone. There are many different examples of how synesthesia could be perceived such as hearing colors or smelling sound or even tasting the shape or different objects. Neurologists have concluded that persons with this condition are not able to control it and automatically done. They have also been able to conclude that different synesthetic events happen at different locations outside the body. An example we discussed in class was how the different days of the week had completely separate locations outside the body and can be recalled by locating the position. Having more than one way to remember a sound or read a word vastly improves people with synesthesia ability to remember extremely large quantities of information. For example the words of this blog would all appear as different colors (with the exception of identical words). Ramachandran and Hubbard were able to determine that synesthesia is a perceived effect after the organized a test in which they sporadically placed 2's and 5's (which look similar) onto a sheet or paper or other similar area and found that people with the synesthesia effect of seeing numbers as colors were immediately able to pick out the 2's from the 5's while people without this condition had to look at each individual number to pick out the 2's. This experiment only works with association of numbers with colors however. There is an example on the webpage which helps understand what it would really be like to have this condition.

The authors were also able to determine different areas of the brain (V1-V5) which are responsible for different visual processing abilities. They found that different areas of the V series could be activated through cross activation without the stimuli of that particular V series being present. They also found that when subjects view color their specific V series number which is responsible for color may not be stimulated.

Apparently there are drugs which can cause these effects such as LSD and Mescalin which could possibly be used to further study this condition. Another interesting stat noted is that this condition is found in a ratio of 6 women to every 1 man. I am very curious as to what would happen if you showed a person with association of color to numbers a number in an opposite or complementary color they see that number as. In addition I’m curious as to what would happen if you showed the reverse of areas associated with things such as days of the week to people with this condition. If anyone has any thoughts as to what might happen please share!

Anomalies in Neuronal Migration

I am still very curious about exactly how neurons develop and upon further investigation I found an interesting article that dictates how neuronal development can be considered abnormal. The article titled MR of Neuronal Migration Anomalies can be found here (http://www.ajronline.org/content/150/1/179.full.pdf+html).

In this study 13 patients with abnormal migratory neurons of all severities were observed using Magnetic Resonance (MR) to image the patients due to its high contrast between grey and white matter. Correct neural migration occurs from developing brains to all parts of the body during weeks 8 through 16 of pregnancy. Continual development also occurs until week 25 of pregnancy. However its during weeks 8-16 when the authors concentrate their study. Any injury to the brain during weeks 8-16 alters the migratory pathway of the neuron resulting in abnormalities such as seizures, mental retardation, and developmental delay to identify a few. The researchers also hypothesize that there is a possibility of genetics that plays a key role in the development of neuronal pathways.

The article states that at a specific area in the brain called the cell-sparse layer is most likely where a diversion of normal growth takes place. They believe that necrosis occurs in this area and further hinders the patient because the axons and places of dendritic connection which have already been established are also affected by the necrosis of the cell-sparse layer of the brain. They are able to determine that the axonal and dendritic connections of the white matter have been diminished due to the necrosis in the cell-sparse layer of the brain. This is called "syndromes with lissencephaly" and is still debated between professionals.

There is still much more to this article that explains in greater detail exactly how and why they believe the things mentioned above. I think it is very interesting how they have determined the information and I would really like to learn even more about other anomalies in neuronal migration
.

what happens during a seizure

While attending the U of M football game against New Mexico State I suddenly became intrigued as to what happens and what causes a seizure when U of M head coach Jerry Kill collapsed and had a seizure following a controversial call with 20 seconds left in a close game during a hot Saturday afternoon. The article (http://seizures.nicheinfo.info/Seizures_What_Causes_Them.php) seizures: what causes them, was just the info I needed to come to my conclusion. After reading this article I learned that what needs to happen in order for a seizure to occur is an irregular discharge of electrical impulses. With even a single irregular discharge the net of neurons connected to that single irregular impulse would also be affected. Although on medications for seizures Jerry Kill was dehydrated and most likely yelling after the blown call which was enough to trigger the seizure that followed. The article states that a lack of oxygen or any metabolic irregularities such as a change in chemical levels can be causes of a seizure. The dehydration would be enough to turn his blood slightly acidic and changed the amount of chemicals entering his brain and the blown call on top of that was enough to cause that sudden irregular impulse in his brain leading to the cascading effect of a seizure.

Second Impact Syndrome

During the season of my senior year of football I suffered two concussions within the same week. After hearing more about concussions (on multiple doctor visits) I became interested as to just what makes them so dangerous. When two concussions occur within a short amount of time there is a possibility of Second Impact Syndrome (SIS) which generally leads to death or being reduced to a vegetative state. I found an interesting article (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2672291/ ) which explains why SIS is so dangerous

The article states that after a primary concussion the body tries to auto regulate the amount of damage to the brain by reducing the amount of blood flow to the brain. This is obviously problematic due to the fact that we know the brain needs plenty of oxygen and other essential items as well as getting rid of the waste products in order for the brain to operate at maximum performance. With an already limited amount of blood flow to the brain this makes the second concussion even more dangerous now that the brain has lost its ability to auto regulate. The article then states that even a non-lethal blow to the head after the initial concussion is sufficient to hinder the brains ability to manage intracranial pressure which leads to a subdural hematoma resulting in death. This can happen in a matter of minutes following the second impact!

I find it very interesting as to how the brains limits blood flow in order to try and minimize the amount of damage. Then again I can’t think of a better way to try and keep the amount of swelling down.

Migration of neurons

I found an intregging artical regaurding how nuerons "know" where to migrate to.  The article is titled Do neurons in the vertibrate CNS migrate on laminin.  Neurons connect to glical cells using a glycoprotein (specificly the glycoprotein laminin) to direct neural migration.  The authors used the brains of rat embryos to test limiting the amount of laminin to determine if it did or didnot affect the migration of neurons in the growing brain.  After the use of anti-laminin antibodies, "pockets" of laminin were found near radial glial fibers.  This provides evidence that this link between the laminin and the radial glial fibers (which provide a pathway for neuron migration) is somehow needed in order govern the role of glial fibers and the migration of neurons.  I found this article to be somewhat helpful but it is still unclear as to how exactly neurons migrate.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC554319/pdf/emboj00270-0085.pdf