The Study of Everything

Of life, neuro, and everything else. 

[nikkialexis77]

4.23.15 Degenerate

Degeneration is a scary thing. Its the brain slowly breaking down, neurons dying, the undoing of the connections that make a human being whole. Neurological disorders have varying causes, but most end in degeneration of part or a whole of a system. 

Let’s talk about a well known disease, Parkinson’s. Parkinson’s can have several causes, genetic or sporadic. One suffering from Parkinson’s has difficulty initiating movement, rigidity of muscles, and sometimes a resting tremor. It results from degeneration of motor neurons. This can be a result of a misfolded protein building up in the cell and causing death. We have temporary cures, like administering L-Dopa, a precursor of dopamine, a neurotransmitter that can help increase movement. But the effects of this are short lived. 

Alzheimer’s is another neurological disorder. In this disease, a build up of plaque in the brain blocks axons and dendrites of neurons causing their degeneration. Soon after, the person suffers memory loss and confusion, and eventually become helpless. To me, this is one of the most terrifying diseases. To lose all memory, all recollection of your experiences, is to take away your life twice. If one cannot remember the events of their existence, then what was the point of living at all? However, there is some promising research happening that may soon find a cure. 

We need to research more ways to cure these disorders. Many neurological disorders are in want of a cure. They have devastating effects, but the more we learn about their causes, the more we can predict and control the effects. 

[nikkialexis77]

4.16.15 TALKING IS HARD

Hi, how are you? Reading this? To me its incredible we can communicate through arbitrary symbols on a page. That’s the essence of language after all, sounds and symbols with randomly assigned meaning that we some how all universally understand. Are we the only species capable of this? Language and communication seem to be a hallmark difference between us and the species around us. However, several studies have shown that apes too are capable of comprehending a written and verbal language, although they cannot produce speech. They have been proven to have the comprehension level of about a five year old. This goes to show that our language abilities are an evolved characteristic. What parts of the brain then make us so much more advanced than chimpanzees?

Let’s look at the parts of the brain that make language possible. Two areas come to mind when mentioning parts of the brain involved in language--Broca’s area and Wernicke’s area. Broca’s area is involved in the production of speech, and damage to this area causes the patient to be unable to speak fluently and use words such as and or but. Wernicke’s area is involved in the comprehension of speech, and damage to this area produces fluent speech without any content or meaning. Difficulties in producing or understanding language are called aphasias. 

More than two areas of the brain are involved in language. Subcortical regions are important too. It’s been shown that stimulation of the insular cortex and regions as deep as the pulvinar nucleus in the thalamus can produce positive and negative symptoms such as speech arrest or speech production. Language is a whole brain phenomenon. Different areas are involved because it takes hearing a sound, interpreting the sound, and attaching an arbitrary meaning with that sound, which has to be retrieved from your memory. So we've developed a system in which we use words, sounds, to represent our memories and perception of the world around us, the meaning. 

[nikkialexis77]

4.9.15 DROGAS

Drugs. They’re presented in society with a very negative image. We grow up being taught to say no to drugs, being shown images of addict’s misfortune, and being scared of the consequences. But how does one become addicted to drugs? There’s more than social pressures and a provocative environment that contribute to drug use. What happens deep inside the brain to cause addiction to happen?

Most addictive drugs, such as heroine and cocaine, cause the release of a neurotransmitter called dopamine. Dopamine is involved in the reward circuit in the brain, and makes activities associated with its release be perceived as pleasurable. Therefore, the drug produces good feelings in the user.

Now, when the person uses the drug for the first time, the nervous system is not ready to handle it. It is an entirely new experience, so the nervous system takes careful note of everything the user is feeling, and then does its best to change and adapt, in order to calm down the imbalance to it. The nervous system remembers this adjustment, so the next time the drug is used, the brain has a response prepared for it already. Because your body can respond to it quicker, the drug seems to not have an effect, so it takes a higher dose of the drug in order to overwhelm the nervous system and cause a response again. This is called tolerance, and is why drug users need increasingly higher doses in order to feel “high”.

So really, drug addiction is a symptom of your brain learning how to respond to a drug, and continuously changing to accommodate greater and greater amounts of the drug. Then when the drug is no longer used, the nervous system has changed so much and is now expecting the drug, that it works to change back to its original state. This process is what causes withdrawals, or the painful and unpleasant feelings a drug user gets when they stop taking a drug.

[nikkialexis77]

4.3.15 Learning in the Long Haul

How do we learn? How do we remember things? Well, while scientists don’t know everything about memory formation, they are well on their way to discovering some of the key mechanisms that make learning possible. 

When we learn, there are physical changes in  the nervous system. Neurons fire when we learn something, and the strength of these connections between these neurons may be responsible for remembering. Take a process called long term potentiation for example. When something is learned, the neuron releases glutamate, an excitatory neurotransmitter that makes the next cell more likely to fire. Glutamate binds to a special receptor called the NDMA receptor. This receptor lets calcium into the cell, and that calcium set off a series of events run by enzymes that eventually put more AMPA receptors into the cell membrane. AMPA receptors are also glutamate receptors that let sodium rush into the cell. So with more receptors in the membrane to let sodium in, the higher the chance that the neuron will fire and make an action potential. This is learning at the cellular level! The stronger the synapse, the more receptors, the more the action is ingrained into your memory. 

There are still many mysteries to learning. Although we know some of the processes by which learning occurs, there is much work to be done. I think if we understood better the mechanisms by which memory occurred, perhaps then we could do more to bolster memory. It’d be pretty neat to be able to remember everything, wouldn't it?

[nikkialexis77]

3.12.15 TANGO

Motor sequences. Patterns of movements we learn and execute. This week, I essentially learned what parts of the brain are used t learn any type of sequence.

In the brain, we have these special neurons called mirror neurons. They’re activated by watching someone do something, and then thinkning about imitating that person. So, we had some awesome tango lessons this week. Our, instructor would say, ‘ok, now move like this!’ and would do some set of confusing steps. And I’d try my best to copy them, and when I did, this mirror neuron system was activated again.

Another part of the brain, the  premotor cortex, takes arbitrary words and helps translate them into actions. Think about it. Words have no actual meaning to our biological system other than what we make up for them. So our premotor cortex helps translate these jumbles of sounds and correspond them with some type of movements. So when the instructor said, do two walks and a link, I knew to take to slow steps backwards and in a kind of circle shape, and then to quickly step right then left. 

The supplementary motor cortex plays a role in learning complex sequences of movements. For me, the tango was quite complex. I’m not a very good dancer. But when learning the steps, this region of the brain was activated, and then even more so, it’s activated when even thinking about moving. So when my brain just thought about what the steps were going to be, then I activated this region. 

Then finally, the primary motor cortex give us the urge to move, and executes the movement. So after I have watched, tried, learned, and it’s time to do the sequence, this area of the brain is activated. And it gets better as it goes! Do you know how when you try something the first time, you’re not very good, or look like an awkward kid with two left feet trying to tango, but by the end, you can do it really well, and like like a tangoing master?! Well, this is the result of a process called long term potentiation, which is just a change in the way that section of your brain works as a result of learning a new behavior. So the new dance sequence actually changed my brain! How long does it stay changed? As long as I keep doing that behavior! 

So, there’s a pretty cool science to learning behaviors. To learning motion sequences. Think about it, this type of learning can even help you become better at sports! I can’t wait to use these methods when I coach...

[nikkialexis77]

3.5.15 Sugar on my Tongue

For as much as we know about many of the senses, taste is something we know relatively little about. We have a general sense of the tastes we perceive--salty, bitter, sour, sweet, and umami-- and why we have evolved to perceive them the way we do. For example, we seem to not like bitter things. Bitter tastes come from receptors on our tongues that interact with alkaloid substances--things that are basic on a pH scale. This is because when we existed thousands of years ago, we ate lots of plants and needed to be able to detect toxins in these, such as atropine in solinase plants. We evolved to detect a taste called umami as well. Umami is the taste of savory, like from meat or Parmesan cheese. This evolved so we would consume better nutrients. Umami receptors are sensitive to glutamate. 

One thing we are not entirely sure on is how the brain interprets the inputs sent to it from the tongue. There are a couple of theories out there. One says that different areas of our tongue are responsible for different senses of tastes, like sugar is in the front of the tongue, however this is a myth. Another suggests that different types of receptors carry information to the brain in labeled lines. This means that once an input is recieved, it travels along one pathway set aside for that specific input, and this sets off the complementary pathway in the brain. So I'd eat sugar, and the sugar receptors would travel along a specific pathway for sugar, and then set off areas in the brain that let me know I'm eating sugar. Another theory suggests that these lines carry information based on more than one input, so each line carries lots of information, and the pattern of how they get to the brain is how we interpret taste. 

We tested this out in an experiment. We first tasted salt, ajinomoto, sugar and m&ms, rinsing our mouths with water in between, and then rated each on their bitterness, saltiness, sweetness, and sourness. Then we drank an herbal tea, tried each substance again, and POOF. I couldn't taste sugar anymore! It felt like I was eating sand that melted on my tongue. The flavor was gone. 

Turns out the tea blocked my sugar receptors, so my brain was no longer receiving info from them. It was as if a whole labeled line was cut off! Does this mean our tongue sends info via labeled lines? It's not entirely clear. Some people still tasted the sweetness, so sweetness varied across people, which could support that our perception of taste is based on patterns of info sent to our brain. 

But for now.. I'm eating a ton of sugar I can't taste. It's quite interesting...

[nikkialexis77]

2.27.15 How to Study Brains

We research the brain. We study the brain. But how do scientists do all this fancy stuff?

There are a lot of ways to do this, but we can just discuss a few.  

Say we want to determine what part of the brain is responsible for controlling pain. We could do an ablation a study. Ablation studies destroy a part of the brain  and then observing the behavior of the subject after the brain tissue has been destroyed. If the behavior is different, one can assume the area ablated is responsible for the some part if the difference in behavior. 

Or we could try and determine where parts of the brain project to and form circuits.  A form of this is called anterograde labeling, and it uses a substance such as PHA-L  that is absorbed by the cell body and moved down the axon to see where the circuit goes to. You can also see where a pathway is coming from via retrograde labeling, which uses substances like flourogold to be taken up by the axons and go towards the cell body. We use these methods to see how neurons form pathways through our brain. 

There are a ton more ways to study the brain, but those were a quick glimpse at  a few I may get to someday perform in the lab. 

[nikkialexis77]

2.20.15 Drugs?

This week focused on pharmacology. It's important to know how drugs can interact with your brain. But what's interesting is defining exactly what we think a drug is. Drugs are any substance your body can't make on its own, and when that substance enters your body, it interacts with your cells and causes some type of change. So, there's the traditionally thought of drugs, the bad drugs, like heroine or cocaine. There's the medical drugs, the prescription pills and shots. Then there could be potentially less thought of items. 

A brief history on some types of makeup: Mascara. It needs to be dark, right? So it can be made from petroleum based products, or plant extract. A long time ago, we used an extract from a plant called belladonna. This was effectively a drug. Belladonna relaxed the muscles controlling dilation of the pupil, making the pupil appear bigger. Widen pupils are a sign of interest, and when one is aroused their pupils widen. Therefore, this old mascara caused women to appear more interested!

Drugs are fascinating. They can alter your mind by changing very simple processes. Say they don't let your neurons reabsorb a neurotransmitter. Well now you have too much in your system. That's how cocaine works. Or they are chemically similar to a neurotransmitter, so they can attach to the same neurons and cause a response. That's how nicotine works. It binds to receptors that activate your muscles. That's why it can make you feel jittery. There's all sorts of drugs, simple substances that cause a disturbance in the flow of chemicals that makes us what we are. That's what I find so intersesting. We are a movement of molecules. Throw in a foreign one, and the results can be mignificent or disasterous. 

[nikkialexis77]

2.13.15 Split Brains

In learning about the the brain, because brains are cool, we have to learn what everything is called. And although tedious, it's necessary. All the areas, the different grooves and bulges, they have names. So the surface of the brain, you can think of it as divided into four lobes. Your frontal lobe is the part closest to your nose, and it's in charge of planning and executing motor movements. Then your parietal lobes are somewhat on the sides of your head, and are in charge of somatosensation, which is just how you perceive things that happen to your body. Then you have the temporal lobes, which are by your temples (shocker) and control all the hearing and auditory stuff. And lastly, the eyes on the back of your head, the occipital lobe, in charge of vision. 

So, remember last week, I was dissecting a brain, my very own sheep brain which is sitting in a jar with my name on it. The best way to remember what all these structures are is to take a brain, cut it open and learn about all these random names thrown at me in lecture. So we did that. BRAINS ARE SO COOL. We took off the pia mater, which is like some shrink wrap that holds the brain together. Then we cut the brain in half! Split brain!! It's just so amazing to me, how these little wrinkles and grooves in the surface of some tissue control everything you do. Like there's this hill on your brain, in the frontal lobe, called the precentral gyrus. It controls all your motor movements. Or in the back of the brain, there's these two balls pushed together that look like a baby's butt. Those are the superior colliculi. Ever flinched because a ball was flying at you or you thought something was moving near you? That's because that little bit of brain is in charge of visual startle, and makes you shy away from visual stimuli you weren't expecting. So cool right?

[nikkialexis77]

2.5.15 Because Brains Are Cool

This is the assignment. For one time each week I'll be writing to tell the world about my thoughts, opinions and cool new things I learn in Neuroscience. Don't let that word scare you though. Neuroscience really is the study of everything, EVERYTHING, and well the brain too. It's worth a read. You'll learn a lot. 

Anyways, I have two main things to rant about. For one, I get amazed at the essence of life. Everything you are, everything I am, everything human beings do--is all driven by the flow of a couple charged up atoms. We call these ions (in our bodies it typically a lot of sodium, potassium, calcium, and chloride doing most the work). Your body communicates with NEURONS, cells with long axons which are just like organic wires in the body carrying signals. And this wire is enclosed in a membrane, the whole cell is, and it keeps what it want in and only lets what it wants into the cell. So say you stimulate a neuron, that is you give it some signal, like something hot, well it goes and causes these gates to open in the axon, and then POOF. A bunch of sodium ions rush in. And this causes the next gate to open, then the next, and the next, and pretty soon this flow of Na ions reaches the end of the axon and releases a signal called a neurotransmitter. This makes the next cell do the same thing. Then, everything you are is just the sum of your brain interpreting all these signals--the rate at which the ions fire down the axon, how long in between each round of firing, how many does it receive at once. It amazes me. Your thoughts, actions, reactions, emotions, all of it is just the result of some ions moving across a membrane and making signals. It's mind boggling. So simple, yet so complex all at once. 

Secondly, I dissected my first brain today! And oh goodness was it cool! Your brain, it's so fragile and durable all at once. Its encased in this stuff that's similar to shrink wrap, but more like rubber so it absorbs all the force if you ever hit your head. And the brain, it's not very hard. It's more squishy like tofu I guess. It would just spread out like jello if there wasn't the shrink wrap meninges around it. 

So yeah. Brains are cool. They're everything we are. The world around us. What makes everything in life possible. To me, that's worth knowing about.