Amnesia

I found amnesia to be very interesting. Amnesia is the loss of memory, usually from hippocampal damage and some times from surrounding areas of the medial temporal lobe. The two main forms of amnesia are anterograde amnesia and retrograde amnesia. Anterograde amnesia is the inability to form new memories after the brain damage; retrograde amnesia is the inability to recall memories before the brain damage. Here is an article that shows other forms of amnesia like Korsakoff’s amnesia and many more.

One of the most interesting things about amnesia is that short-term memory or better known as working memory, which is memory we use at the time, is not affected but long-term memory is. You can take a patient with amnesia, have them memorize a few numbers, and after a while without other distractions you can ask them to recall the numbers and they will, but if you give them some other task to complete, they will not remember the numbers that they were given at the beginning, this probably happens because when the patient has to start thinking about something else the memory of the numbers has to be stored in long-term memory, but since it is not working, it doesn’t happen. Another interesting thing about amnesia is that when patients with it see them selves on a picture they assume it is not them and that the person standing there is someone else, while when they look in the mirror the recognize them selves and are not shocked by changes from age, mostly because we know when we see a reflection in front of us that it is us standing there.

Severed Corpus Callosum

This week’s main topic of interest was the severing of the corpus callosum, because I find it very interesting that we can damage the bridge to the brain’s hemispheres and live a normal life.

            The severing of the corpus callosum became famous for treating epilepsy, which are continuous episodes of extreme synchronized neural activity, the activity usually bounces back and forth from hemisphere to hemisphere, which keeps it going, therefore severing the corpus callosum keeps the excessive neural activity from damaging the other side of the brain, and it stops much quicker than it did before.

            People with a severed corpus callosum are referred to as split-brain people, these people don’t have many problems from the severing of the corpus callosum, which you think they would from damage to the brain. At first split-brain people might have trouble adjusting to their new life style, because their brain needs to get used to the lack of communication through its main source the corpus callosum, but that isn’t the only connection between the two hemispheres, there are very small ones along the two hemispheres that help out after the corpus callosum is severed, although not as powerful they are somewhat affective.

            Some of the problems that come with the severing of the corpus callosum is how the hemispheres perceive things. Our brain works in mysterious ways, the left hemisphere controls the right side of the body and the right hemisphere controls the left side of the body. Because of how the brain perceive things sometimes even if something is seen by the right hemisphere that would be on the left visual field, we can talk about it even though we might be able to point it out, and that is because the part of the brain that works with language is on the left hemisphere, while we might notice emotions a lot better on something we see in our opposite visual field, since the right hemisphere works with emotions. Here is a video of a man named Joe with a severed corpus callosum and how his brain works in different procedures.

Brain Anatomy, Development, and Plasticity

Strokes are very interesting, I’ve never thought of them being a big problem until recently, where everyone I know even if by connection has had, or knows someone that has a had a stroke. There are two types of strokes the most common one being Ischemia, which is caused by a blood clot or any other form of barrier in an artery. The second and less common form is Hemorrhage, which is caused by a ruptured artery, much different than the Ischemia, and how it is handled. There are warning signs to recognize if someone has had a stroke, those signs are not hard to check according to this article.

The most interesting part I found about strokes is that much of the brains mechanisms can be saved via cautionary management. E.g. if someone has had a stroke you want to keep their core temperature low, it seems that cooling of the body keeps it from rapidly declining in harmful processes. Another thing that can be used is marijuana, but it’s shown to be more effective if taken before the stroke. Marijuana decreases the release of glutamate in the brain, and an overflow of glutamate causes cell loss, marijuana also releases anti-inflammatory chemicals that might help with swelling from everything going on, but like any other drug it has to be taken within a few hours of the stroke the sooner the better. There are other traditional medicines that can help with strokes, e.g. tissue plasminogen activator (tPA), this medication dissolves blood clots, so it would work with an Ischemia stroke while it might make Hemorrhaging worse, but not extensively. Another big help for recovering from a stroke is to start exercising what was damaged as soon a possible; it is kind of like rehabilitation for the brain. I hope you all find this as interesting and helpful as I did. Here is a video on how a stroke damages the brain.

Synapsis, Drugs, and Addiction

Should alcohol be a legal drug? If alcohol is the most common abused drug then why is it legal, when it causes many problems, like car accidents, the driver killing him/herself and/or passengers and/or other drivers on the road. There are two types of alcoholics’ type I (or type A) and type II (or type B), type II being the most dangerous one in my point of view. Type I gradually develops over time, usually after the age of 25, and those who develop it, may or may not have relatives that are alcoholics. Type II develops more rapidly, and its usually before the age of 25, most of them have relatives that are alcoholic and it usually occurs in males more so. Alcohol was abolished in the past, but of course it was brought back. I believe alcohol is one of the worst drugs because it is legal, so it becomes a product easier to abuse, specially now that they have flavored drinks like lemonades, or cherry limeades, or watermelon, these are all things that make it all the more attracting to kids and younger crowds. Alcohol doesn’t only cause senses impairments, and brain damage on high doses, but if happen to overdose on it you could die from alcohol poisoning as this article points out. My personal view is that alcohol should be banned, or there should be more restrictions to acquiring it, that way there are less cases of car accidents or deaths from overdose in our society. Here is a video on how to recognize addiction.

Nerve Cells and Nerve Impulses

My topic of interest of this week was Glia (neuroglia) the reason being that they have so many functions. A while back Glia was thought to hold neurons together hence the name, which is derived from the work glue in Greek. This article helped me understand a little bit more of what glia cells do and other functions like Satellite cells which are not mentioned in the book Biological Psychology 11^th edition by Kalat. Astrocytes are star  -shaped glia that help axons (the cord that send messages in neurons) synchronize, which enables neurons to send messages in waves, they also help by removing waste that is created when neurons die, astrocytes also control how much blood flow each brain area receives giving it more nutrients to help you think better. There are also Microglia, which also help remove fungi, viruses and other microorganisms, behaving like the immune system. Other Glia focus in forming Myelin sheaths (a substance made up of fats and proteins that surround and insulate areas of the axon in neurons to help transmit messages faster) these Glia are the Schwann cells found in the periphery of the body, and Oligodendrocytes found in the spinal cord and brain. What I find very interesting is how Radial glia help during the embryotic development period by guiding the migration of neurons and their dendrites and axons to where they belong, then when the development period is over most become into astrocytes or oligodendrocytes or neurons. So I leave you guys with this very interesting video on Glia cells that might help on areas I didn’t cover.