Prenatal Brain Development: From Conception to Birth

I absolutely love babies and I've always been fascinated with fetuses, ever since I saw pictures in my health book in high school.  I thought the fetuses were cute and how they developed was pretty amazing.  When I read the the text, I noticed that the book didn't go into much detail other than Figure 5.1 and 5.2, which shows how the CNS is developed and the brain at the 4 stages.

In the first trimester of a pregnancy, the neural tube forms from the neural plate, which folds over onto itself.  At four weeks, the neural tube will become the forebrain, midbrain, hindbrain and spinal cord of the fetus.  "By week 7, the first neurons and synapses have formed and allow the fetus to make its first movements and allow the brain to develop sensory input," UCI.  Week 8 is the last of the embryonic stage and by this point, the hindbrain has began to regulate the fetus' breathing and heartbeat.  It is crucial that no alcohol, drugs, or smoking be done during this period of the embryonic stage (conception to 8 weeks), since the fetus is growing rapidly.

In weeks 9 and 10 (fetal stage), the nervous system is functioning and the brain is forming 250,000 neurons per minute!  From weeks 9 to 12, the fetus has reflexes, the baby moves without the mother feeling it, the sex organs develop, and the spinal cord has nerves that allow movement.  Myelination also occurs, as well as the presence of gyri and sulci on the brain in the second trimester.

I chose this video because it goes more into detail on what occurs during the prenatal development of the brain.  It states that, "Between week 8 and 26, the cerebral cortex grows to cover the midbrain.  By week 28, the cortex increases in surface area, becomes wrinkled, and folds in the skull."

From weeks 19-26, the fetus has developed motor neurons and the mother will be able to feel the fetus kicking and moving around, cute, right?  By this time, the nervous system is joining together, the auditory and visual systems are heightened, and if a light is shined on the mother's belly, the fetus will try to shield their eyes.  That's adorable!

The rest of the trimester, the baby continues to develop at a slower rate and can distinguish certain sounds, songs, and recognize the mother's voice.  All of this takes place in about 40 weeks and a newborn's brain is only a quarter size of an adult's!

Alcoholism: Genetic Or Environmental?

There's nothing more that I love than being able to incorporate my minor (Addiction Studies) with my major, (Psychology).  Personally, I have never experienced living with an alcoholic and drinking is such a normal activity at family gatherings.  Due to the fact that we aren't around anyone who deals with alcoholism, everyone has a drink at parties.  Drinking is seen as a normal activity and some people are more prone to becoming alcoholics, whether they are Type 1 or Type 2.  Every time my brother has a beer, my mom says, "no te hagas un alcohólico!"

Before we can discuss alcoholism being genetic or environmental, we need to understand what alcoholism is.  According to our textbook, alcoholism or alcohol dependence, is the habitual use of alcohol despite medical or social harm, (pg. 77).

This video, explains how alcohol affects the neurons and how it blocks the glutamate, the excitation neurons.  The inhibitory neurons are called GABA and both of these neurons balance each other out, until alcohol is consumed.  Once it is consumed, the glutamate neurons are suppressed while GABA neurons are increased.  The increase of GABA and decrease of glutamate, cause a decrease in brain activity.  The glutamate decrease causes neurons to process information slowly and only the largest signals are able to be processed.  With the increase of GABA, you can think with more clarity, but less often.

There have been studies conducted on twins and adopted children* to determine if alcoholism was either genetic or environmental.  With the twin studies (second link), it was determined that if one twin was an alcoholic, the identical twin had a 76% chance of being one, while the fraternal twin had a 26% chance of being an alcoholic.  Both of these videos have information on the twin studies and on environmental factors of alcoholism, which is why I chose them.

Environment also plays a role in alcoholism.  People drink to deal with abuse, depression, stress and conflict with family, or when they socialize, etc.  Not only that, but children who grow up in families where drinking is seen as "normal" are more likely to become alcoholics.

So, is it genetics or the environment that is the cause of Alcoholism?  Alcoholism is 50% genetic and 50% environmental!

*Graphic images shown after 5:18.

For more information on how alcohol affects your body, and each part of your brain, click here!

What Is Multiple Sclerosis?

As we continue on with this course we come across new information and information we have heard of before, but haven't learned much about.  That was the case when I read about Multiple Sclerosis or MS, as it is commonly abbreviated.  People hear MS and automatically think of paralysis and wheelchairs, however that is not the case for most people who are diagnosed with MS.

So let's begin, what is MS?  MS is a disease that attacks the Central Nervous System (CNS), which includes the brain, spinal cord and optic nerves.  The immune system attacks the myelin sheaths that cover the axons and they damage the nerves inside.  The immune cells enter the brain and purposely attack the myelin, which in turn causes the nerve signals to be interrupted and causes sclerosis, which is scar tissue that has formed.  The attack of the immune cells on the brain, spinal cord or optic nerves, causes inflammation.  In this video, a simpler explanation of MS can be watched.  

An MRI can be done in order to see if there are any lesions in the brain that may be causing the MS.  In Courtney's story, two lesions were found in her brain that had abnormal tissue that were the cause of Courtney's MS symptoms.  When the nerve signals aren't able to move to the next axon, they cause symptoms that may or not be temporary.  The symptoms are: numbness, tingling, paralysis, muscle spasms, loss of balance, blindness and other problems.  Since the myelin sheaths can be destroyed in the brain, spinal cord or optic nerves, there are different symptoms that each person with MS experiences.    

What causes this autoimmune disease?  Doctors aren't sure, but they speculate that it may be genetic, environmental, due to infection, viruses or even the consumption of too much salt.

Like I said before, paralysis does not occur for every person who has MS.  Most of the people who suffer from MS, have Relapsing-Remmitting MS.  This type of MS, is the least aggressive and is pretty manageable with exercise, a healthy diet and plenty of rest.  Remission occurs shortly after the attacks and the person with MS can function normally, for the most part.  However, all types of MS (there are 4) can worsen as time goes by, and can lead to paralysis, blindness and the other symptoms stated above, according to where the myelin sheaths have been attacked.  

Unfortunately, there is no known cure for Multiple Sclerosis since there isn't a way to repair the myelin sheaths that have been disrupted by the immune system cells.  Diet, exercise, plenty of rest and medication can be used to control the inflammation caused by the immune cells.  For more information on MS symptoms, causes, types and treatments, click here!