Types of stroke.

Hello my dear reader's!!!!!!!

Today Stanford will tell you about the types of strokes in our brain. Just watch the video below:

Here are the notes that you can revise after watching the video:


Neurons communicate through Ions. Ions are passed through the cell membrane and the inside of the cell is negatively charged while the outside is positively charged. The neurons send electric signals to communicate known as action potential. The difference between the cell's inside and outside atmosphere is maintained by the proteins in the cell membrane.
They do so by pumping certain ions inside and certain ions outside,this pumping actino requires energy.
Neurons only work in aerobic conditions and they don't have their own energy stores. Brain only costs 2% of body weight, but requires about 20% of cardiac output, and 15% of oxygen take from the lungs. The blood to the brain reaches from the aorta is taken up to the brain by the carotid artery,
which takes 70% of it. The other 30% is taken up by basilar artery and verebral artery. This two artery are joined the base
of the skull and are then divided into six parts (2 parts each) -

1. Anterior Cerebral Artery.
2. Middle Cerebral Artery.
3. Posterior Cerebral Artery.

The Circle of Willis is the place where all these arteries join to provide the brain with blood. This circle joined the right and left artries so that if one artery (either left or right) is not working, then the brain will still receive the blood instead of no blood. Now there are also many other deeper parts in our brain, this parts will get supplied by different arteries. If this arteries don't work properly, that certain part might not be able to function properly.
For example, if the blood does not reach the Broca's and Wernickel's area, this parts will stop working and that person might suffer from Broca's Affesia, a disease in which that person will have language related problems.

A stroke is defined to be an abrupt onset of focal or global neurological symptoms, caused by ischemia or hemorrhage.
Ischemia means restriction of blood in Greek. And it is usually caused due to factors in blood vessels, with resultant damage in tissues. Tissue damage is caused by shortage of O2 or Glucose.

Hamorrhage is discharge of blood from blood vessels AKA bleeding. Bleeding in the tissue or around the brain. Their are 3 types of strokes, Ischemic stroke, Intracerebral Hemorrhage, Subarachnoid Hemorrhage. Ischemic Strokes are usually caused by blood clotting in the brain which will result to no O2 and glucose supply to the brain. Intracerebral Hemorrhage is bleeding in the tissues and Subarachnold Hamorrhage is bleeding around the brain.

Warning signs of Stroke:

1. Sudden Numbness on the face or any other body part, especially on the one side of body.
2. Sudden Problems in speaking or understanding.
3. Sudden, severe headache with no known cause.
4. Sudden trouble walking, loss of balance or coordination, dizziness.
5. Sudden trouble seeing with one or both of our eyes.

If a patient walks in and says he/she has a stroke, we can do the image studying of the brain to confirm that, the images show us what type of stroke it is or either it has an other cause such as tumor, infection, epilepsy. Imaging also tells us how better the brain is getting blood from the blood vessels. Their are two methods of Imaging, MRI an CT scan.

We can also use the cerebral angiography scan to determine the stroke. The main symptomes of strokes are usually seen in people with High blood pressure, diabetes, people who smoke, drink or intake tobacco.

Ischemic stroke is caused when the thrombus is formed which leads to vessel occulsion leading to O2 depletion leads to membrane ion failure which leads to cell swelling and then cell death. Some thrombi take time to form but there are some other thrombi that are formed in the heart and are then sent to the brain from the heart. Some strokes can also be temporary but we must remember that they may be a sign of a stroke. tPA is a method to diagnose the deficits of stroke, but it is not very much effective. The occulsion of a cerebral vessel is followed by formation of a central irreversible infarct, with a peripheral zone, the penumbra, where the tissue is variable due to partial preservation of blood supply via collateral vessels. CT Perfusion shows up the penumbra and infracted area. CT Scanning uses the X-Rays to make a
photo of the brain, the X-Rays are projected to the patient by the X-Ray generator which rotates around the patient to get a good view of the brain, the image of the brain is regerated by a process known as Back Projection as the X-Rays are changed in velocity when they interact with the tissues. MRI works with the help of the photon molecules or molecules containing photons, the MRI take advantage of the photon as they spin at a certain frequency at certain chemical environment, so we use different photons for different tissues, the photons when are bought in an magnetic field, then releases some enery as protons which we can record as they pass through the tissue to get an image of the brain. Rcently, Stanford University and other Universities have made a device that can go through the artery and the surgeon will pass the
device until the surgeon see's the thrombus, afterward's, the device will pull out a string through the clot, and will then turn the string into spiral shape so that the thrombus is stuck in it without any problem and will then just drag the thrombus with the help of the string and take it out. Another thrombactic device is also there that can relatively suck the clot in it and then the device can be taken out of the artery. If the thrombus is sent through the heart, after it is removed, there are sligth chances that the heart might send another thrombus again, which would again cause the ischemia. To make sure that this does not happen, the patient is passed through certain medication after the thrombus is removed from the artery.
The cerebrovascular system is the only route for energy supply to the brain. Blood vessels are lining organs that are under constant state of vascular remodeling. Acquired and cognital problems of this system are important causes of stroke.
In hamorrhage, the blood vessels spell the blood in or around the brain, and as a result of that, that particular vessel does not supply that particular brain part with which it is associated and this leads to ischemic stroke. More people die because of hamorrhagic stroke than the ischemic stroke. The causes of hamorrhage are divided into Primary and Secondary causes, primary cause of hamorrhage is hypertension etc. Ischemic stroke can also be converted to hamorrhage as in
ischemic stroke the blood is not able to reach in the brain which can make the vessel blast as the thrombus won't allow the blood to pass through the artery and then the artery will not be able to take on the blood pressure and will blast off.
Ischemia can also lead to hypertension which would lead to hamorrhage. Surgery is the best way to treat hamorrhage but there are chances of accident in surgery which can lead to brain damage. Aneurysms are the defect in blood vessels where the blister's form. We don't know why the aneurysms occur. The people who suffer from aneurysms have brother's and sister's who also suffer from this aneurysms, this makes us think that there is some genetic problems related with it. The larger the aneurysms the bigger the chance to blow. There are several causes of SAH (Subarachnoid Hamorrhage) such as hypertension, alcohol, pregnancy, drug or cocaine, smoking.
 

Aneurysms usually happen where two arteries join. Aneurysms can be found in a Stroke, Seizure, or a headache pain.
We can tell if a patient has SAH if he is reporting a very worst headache of his/her life, nausia, vomiting, photophobia, neck pain, less control over eye or face, altered level of consciousness, sential headaches (warning leaks) may proceed major, clinically divastating SAH as in half of the cases. First thing to diagnose a SAH is to get an angiographic study of it. We can also do a 3D angiogram. We can treat aneurysms by surgery and enduvascular coiling. In the surgery, we first make a small window in the scalp to look inside the brain, and then we look through a microscope in it, find the aneurysms and then tie a clip around the aneurysms, this would not allow the blood to get into the aneurysms and so the aneurysms
will not bleed out. In endovascular coiling, we tie the aneurysms from the bottom to the top so that the blood can't enter into the aneurysms. The coil comes of different types and sizes. The endovascular coiling can be done with the Primary treatment, Ballon assisted treatment, and Stent assisted treatment. In primary treatment where the neck is not to much large, we just coil the aneurysms, but in ballon assisted aneurysms, we need to use a ballon so that the coil did not fall back to the vessel. There is a device known as flow diverter that can divert the flow of the blood into other blood vessel so that the surgeon can perform the surgery. Arteriovenous Malformations is an abnormal collection of blood vessels wherein
the arterial blood flow directly into the veins without proper capillary beds. Cognitial , but may enlarge with age, this may involve an abnormality or dysregulation of vascular development or remodelling. Usually in AVM's, they are seen like very large capillaries and the veins in AVM usually loss the two layers of their walls, as well as we are not able to see the brain tissue between them, this condition is named as enciephalomalacia. This may be due ischemia at that place or due to the hamorrhage as the veins are carrying blood at high pressure and they are not accustomed to it. This disease usually
is diagnosed at the adulthood as it starts creating problems at that time and it is a rare disease (1-2 people per 100,000)
We use CT (CT Angiography),MRI (MR Angiography), or angiogram to find AVM's. We can cure AVM's by using microneurosurgery, which is very good method for curing the less sophisticated AVM's as well as which are located on the upper side if the brain. AVM's might have been in the patient from their birth or it might have been developed with age but it usually is within the patients at their time of birth. The AVM usually occur when the capallaries are not able form the correct way and they grow thicker and thicker with the time. The AVM can also be treated with the help of Stereotactic Radiosurgery, in this process the AVM is cured with the help of radiation and this is only done when we usually cannot acces the AVM
surgically. We use Endovascular Embolization to make the microsurgey or the Stereotactic Radiosurgery more effective and this all is known as Multimodality approach,i.e., using two or three methods together to cure the Anteriovenous Malformation. The CyberKnife Radiosurgery is made by the Stanford Scientists and it is used to target the particular area directly by an image guided robot. Embolization helps us to get a 3d graph of the brain or the Anteriovenous Malformation as well as helping us to decide weather it is okay or not to do an surgery. We can also know about the risks of performing
a surgery there and also introduce flow-directed micro catheters to the patient's body so that will be assisting in the furture processes as well as to inject liquid in the blood which can literally block that portion of the blood vessel(AVM).
Galen AVM is a type of Anteriovenous Malformation in which the AVM is much dilated than the usual.

Basics Of Neuroscience

Hello Friends!!!!!!!
Today, in this article, I would be writing about the basis of Neuroscience.

First of all, I would like to tell you what is Neuroscience?

Neuroscience is a branch or part of science that  mostly deals with how our brain works. And this is one of the part of science that can tell you that your brain is not just a simple brain but it is really more complex than even a super computer. It's complexity is really hard to solve and study. So, in this article, I will only write about some of the basics of Neuroscience and also I recommend you to read my article which deals with the Neuromatrix of pain, i.e., how is pain caused and it tells about the parts of our brain involved in discovering pain.

So, let me first start with the basis of brain anatomy. Scientists have divided the brain into three parts in common. They are:

1. Cerebellum
2. Cerebrum
3. And Medulla

First I would like to talk about Cerebrum. The Cerebrum is the part of our brain that almost processes all the data that comes in our brain through the spinal cord or all the information that comes into our brain. The image below shows the Cerebrum and it's four parts:

Human Brain

The cerebrum is again divided into four parts:

1. Frontal Lobe
2. Parietal Lobe
3. Occipital Lobe
4. And Temporal Lobe

First let me talk about the Frontal Lobe, this part of our(Human) brain is basically involved in planning and reasoning and all the other types of higher level functions that only human's can perform. More specifically, The Prefrontal Cortex is the part of our brain that is involved in higher order functions. And this part part, i.e., The Prefrontal Cortex, is only found in the human brain, that means that it is the special part that allowed us to perform the functions that animals cannot do.

Prefrontal Cortex

The image above shows the Prefrontal Cortex in green color. 

Now moving towards the other part of our brain, Parietal Lobe.

This part of our brain is mostly involved in the processing of movements. This part of our brain also helps us to keep an record of where our body parts are located in space, for example, close your eyes for some time and after you close your eyes, you still know where your body parts are or where you leg is right now, where you fingers are right now, so this is the part that makes that thing possible, or in other words, it contains a type of blueprint of all your body parts. 

This part also works in coordination with your occipital lobe which is involved in processing visual signals so that you are able to pick up a pencil when you see it.(discussed later)

As I have already said, that the Occipital Lobe is involved in processing visual signals. But for the people whoa re blind from birth may also use this part of their brain to process the auditory signals, it is usually found that the people that are blind from birth, have a greater sense of audio then any other normal person, the reason behind this is that this people usually train their Occipital Lobe to process audio.

Next comes our Temporal Lobe, the Temporal Lobe is a part in our brain which is involved in processing audio signals. It also contains the part of our brain, known as Hippocampus(HI-PO-KAM-PUS), that is involved in processing the memory portion, that is, the thing that we need to remember are processed here and are then sent to long term memory. It is like the gateway of the memory to be remembered. But one thing should be noticed that it only makes us remember the things but it does not store them, it sends that "thing" to the respective Lobe or Cortex it belongs to. For Example, the memory of audio will be sent to the Temporal Lobe, the memory of vision will be sent to the Occipital Lobe etc. Afterwards, this all the memories can be combined to form a image of what happened in the past or the thing we need to remember.

Hippocampus.

The Occipital Lobe also sends the signals to the Temporal Lobe and Parietal Lobe, for recognizing and picking up an object. The Temporal Lobe recognizes the object and the Parietal Lobe plans our actions to pick up the object.

Now we come to the part of Cerebellum, the Cerebellum is usually involved in coordinating motor functions, i.e., the functions of movement. The movement signal after getting processed in the Parietal Lobe, it reaches the Cerebellum. The Cerebellum also controls reflex functions. For Example, if you try to hit a trained person in self defense techniques, such as Bear Grylls, you will find that they have taken the decision to attack you in the correct manner in less than a second, the reason behind that is that the signal did not go to the Cerebrum, instead the Cerebellum used the neural connections in it to perform that action. And also you can modify the neural connections in the Cerebellum by practicing regularly.

Last comes our Spinal Cord, it is a part that takes signals from our brain to the body and also from the body to our brain.

I cannot write more than that right now as I am tired, sorry for any mistakes in this article.

Thanks for reading!!!!!!!!!

Neuromatrix of Pain

Hello Again!!!!

In this post, I will be talking about the neuromatrix of pain, or in simple words, the way our brain understands the pain that is being felt. It's really a point of much debate in today's world that how our brain receives and processes the pain.

So, let's start.

First the pain is experienced by the nociceptive receptors located through out the body and nociception means pain, so in neurology we always use the word nociception instead of pain. So, first the pain is experienced by your nociceptive receptors and then it is sent to the Reticular Formation located in the Brainstem or Spinal Cord.
Now, Reticular Formation is the first part of the brain that receives the nociceptive signal and Reticular Formation helps us to get our concentration on that pain. Concentration plays an important role in the sensation of pain. And if we are concentrating on something else than the pain which is more important than the pain, then the Reticular Formation may not give give attention to pain and we might not feel it.
After it has passed the Reticular Formation, it goes to the Thalamas. Thalamas is a very main part in our brain which plays a very important role in almost every action of ours. The nociceptive signal goes to several specific nucleus of the Thalamas. They are:

1. Ventral Posterolateral Nucleus(VPN Nucleus)
2. Medial nuclie of Thalamas.
3. Intralaminier nuclie of Thalamas.

The nociceptive signal after passing the Reticular Formation reaches the Ventral Posterolateral Nucleus or VPN Nucleus. This part of the Thalamas has very much food connections with the Somatosensory Cortex, which is located in the Parietal Lobe, and it plays an important role in accessing the intensity and the location of the pain.

Medial Nuclie of Thalamas has better connections with the motor cortex located in Frontal Lobe which plays an important role in generating motor functions or the movements related with the pain. For example, if you pour hot water on your hands, then the motor function will be removing your hands from the water, and thatt movement will be generated with the help of Medial portion of Thalamas which sends the signal to motor cortex.

Intralaminier Nuclie of Thalamas plays an important role in seeking attention towards the pain.

Now we come to another part important for seeking pain. After passing through the Thalamas, the nociceptive signal reaches the Primary and Secondary Somatosensory cortexes (S1 and S2). Scientists believe that the S1 is included in discriminating the various properties of pain and the S2 is usually involved in recognizing pain and remembering last pain. Experiments has also confirmed that the higher the activity in S1, the greater the pain will be.

But in an experiment, several persons were hypnotized and said that the pain that they will be given will very much than the pain's real capacity and others were said that the pain would be lesser than the normal capacity of the pain. When they were given a little amount of electric and their brain parts activity was measured, it was found that the activity in S1 was not changing with the intensity of the pain. The persons who were said that the pain will be greater were having the same activity level in S1 as the person's who were said that the pain will be lesser. In that experiment, the scientist also found that the Anterior Cingulate Cortex had different activity levels in the persons. Anterior Cingulate Cortex is involved in the affection component of pain. And we should remember that affection leads to emotion, and emotion will give you pain. So, the more the activity level in Anterior Cingulate Cortex, the more the pain you will feel.

But neuro scientist Burkhart Bromm said that the Posterior Cingulate Cortex receives the nociceptive signal before Anterior Cingulate Cortex. The Posterior Cingulate Cortex receives the signals after 220 milliseconds after the nociceptive signal starts.
He thought that this part is included in the affection component of pain, and we should remember that the affection leads to the creation of emotion which give rises to feeling of pain. So, the more the activity level in Posterior Cingulate Cortex, the more the pain.

But as you have observed that when an pain is felt, then you do some movements to escape from that pain, in the movement part, the Parietal Lobe of our brain plays an important role in generating a signal that would help us move. The movement done here is done with the help of Parietal Cortex which plays an important role in also planning other movements.

One another part of our brain also plays an important role in pain, that is the Hippocampus, the part of our brain which is involved in the formation of memory, and the memory might play a role in pain because when we feel a pain, our brain tries to associate it with the past memories of the pain, and the if we are experiencing the pain for the first time, our brain remembers the pain and even when we think about the pain, we might get the feeling of the same pain because of the release of certain hormones at that time.

This all parts work together to give you the feeling of pain and this is the reason that there is no certain area of our brain that we can remove to get rid of the feeling of pain, instead, many parts of our brain work together to give us the sensation of pain.

Thanks for reading this article.