Coming soon…
Do you know where to tickle my brain? Anatomy of laughter
November 9, 2009A neuroanatomist’s journey through an episode of stroke
November 9, 2009
How it feels to have a stroke: An experience of a brain scientist
My colleague Dr. Taylor’s precious and unique story
Dr. Jill Bolte Taylor is a Harvard-trained and published neuroanatomist who experienced a severe hemorrhage in the left hemisphere of her brain in 1996. On the afternoon of this rare form of stroke (Arteriovenous malformations;AVM), she could not walk, talk, read, write, or recall any of her life. It took eight years for Dr. Jill to completely recover all of her functions and thinking ability. She is the author of the New York Times bestselling memoir My Stroke of Insight: A Brain Scientist’s Personal Journey (published in 2008 by Viking Penguin) and was chosen as one of TIME Magazine’s 100 Most Influential People in the World for 2008.
The anatomy of autism
October 26, 2009
Coming soon…
Increased hippocampal size after lithium treatment in bipolars
October 26, 2009
Coming soon…
Cerebellum: Dark side of the moon
October 26, 2009
Coming soon…
Hippocampus: The seahorse that rides you…
October 26, 2009Coming soon…
Amygdala: Yes, I love you and I remember you.
October 26, 2009
We are living creatures. Humans, animals…We have to survive in life. We communicate through people, as we do not live alone but in a society. For that, we use two aspects. Cognition and emotions. So here are the key words before we start “amygdala”.
Key words for amygdala
Survival
Communication
Emotion
Now..Let’s do the Five Ws and one H of the amygdala!
Amygdala means “almond” in Latin. See the two pictures below. The one on your right is an MRI image of amygdala on a coronal view (the way you would cut a bread; sorry for the analogy; I am so anatomist). Amygdala resembles an almond, doesn’t it? The Ancient scientists were creative.
Where is amygdala?
The human skull is composed of different bones. One bone just over your ears, put your finger over your ear, here is your temporal bone. The lobes of the brain also lie in these bones with the same names. So your temporal lobe is under your finger now. Why did they name it “temporal”? Well, it comes from the term “time”. The connection is one starts to have grey hair starting from there as time goes by.
Here is a picture of Ben Stiller, one of my favorite actors, as I like romantic comedies. And here is more information for you. Open the temporal lobe and look inside, the medial temporal lobe (medial means close to the middle of something in the body, not close to the outside) as we anatomists call it. You will see 3 brain structures there. In the middle hippocampus, above it amygdala, under the hippocampus parahippocampus. And when someone says medial temporal lobe, basically you remember these structures and you remember that they are about remembering; e.g. memory. So the temporal lobe; grey hair; comes from “time” and medial part is about memory. Interesting, no? When it was named, it was not known that it was about memory.
A person is walking at the street approaching you. You just don’t like him and do not want to talk to him. Let’s say he is a politician, not your favorite. You are in the Middle East and getting ready to take off one of your shoes to throw at him. So here are the basic questions about your brain? How did you recognize him? Who is he? Amygdala is not in the scene yet. It is your hippocampus (next post) that gives you the facts. A list of information about him. Your reaction is a result of your emotional history; why are you reacting this way? Not because you remember his name, etc. But you should remember all these before you react. Amygdala is now in the scene with its role in “emotional processing”, “emotional learning” and “emotional memory”.
Let me take you again to the same street. Now it is after midnight; and not a safe place of the city to hang out after midnight. But you are there somehow. A “Oh-my God” looking not so well dressed guy stops you in the middle of the street where you are alone and asks for some change. You say “Sorry, I do not have any”, then the next thing you realize is a shining knife in dark. What do you do? You escape with all the blood in your legs, or you have a fight for your life. So what do you need? Fear. You should have the crisis plan. Hippocampus again tells you “this is a knife and can hurt or kill you”. Amygdala says “and you should freak out,now!”. Stress (too much is harmful though) is the key for survival for that night. Thanks God you have an intact amygdala for some emotional processing.
Emotional learning/Emotional memory/Emotional processing (particularly fear)
The amygdala as a key brain structure for acquisition and storage of fear memory traces. Emotionally significant experiences tend to be well remembered, and the amygdala has a pivotal role in this process. If you have an ordinary dinner with an ordinary friend, or have a dinner where you propose to your future wife, it is more likely that you remember the one with the ring in your pocket. Let me say that it is also important for your survival (so that the wife does not nag you when she asks you what she was wearing that night).
Functional neuroimaging studies have provided strong support for a critical role of the amygdala in emotional processing. Research on the neural systems underlying emotion in animal models over the past two decades has implicated the amygdala in fear and other emotional processes. Behavioral data suggest that fear stimuli automatically activate fear and capture attention. This effect is likely to be mediated by a subcortical brain network centered on the amygdala.
Smelling
Amygdala and the other structures of the medial temporal lobe where it is located is a member of the limbic system. The system was there in the brains of the first mammals. So amygdala is a part of the oldest region/system of the brain. What does it tell us? Something common with animals. Reproduction, sexual behavior, aggression, response to stress (fight or flight), emotions, survival. Amydala is important in smelling in our animal friends. Sexual arousal and survival (you smell the danger). This role and part of amygdala is not a big deal in humans, though.
Reward
Social perception
Higher cognitive functions (long-term memory, working memory, decision-making and attention)
Stress response:
This is good. But you can be in trouble on a plane when amygdala and the limbic system dominates in your brain if you are afraid of flying; sending “there is danger, panic, panic!” messages when there is none. Panic attacks? Yes, we have amygdala in the scene.
Psychologically induced stress with the blood pressure-regulatory system
Sexual behaviour
Who has abnormal amygdala?
Anxiety disorders (such as generalized anxiety disorder, post-traumatic stress disorder, panic attacks; panic disorder)
Epilepsy; temporal lobe epilepsy (my PhD dissertation topic)
Substance abuse; drug addiction
How can we study amygdala?
Structural MRI studies where we have the volume of amygdala in several diseases (such as in major depression) have inconsistent results. There might be different reasons for that, but one reason might be amgydala is composed of different nuclei groups, oranges and apples together, these nuclei (plural of nucleus) function differently. Functional neuroimaging studies (functional MRI being again the most popular), animal studies are very useful as well.
Some links to amygdala or Miss. Amy G. Dala.
Anatomy of the brain: Amygdala
The Role of the Amygdala in Fear and Panic
Neural pathways to long term memory: Hippocampus and amygdala
The king of amygdala anatomy and pathology: David Amaral from University of California, Davis
A recent book by J. LeDeoux; another king; Emotional Brain
A youtube video: Amygdala-the cause of all your anxiety.
A youtube video: Structural and functional neuroimaging of the amygdala
Duration- 53:06 min
A song by the Norwegian scando-pop duo Frost “Amygdala“
http://amygdala.net/
fMRI (Functional magnetic resonance imaging)
October 25, 2009
You are running. 1K, then 2K. Which part of your body will get/need the most blood/oxgen? Which muscles? Of your feet and legs. You ate your lunch. It was a buffet. Which part of your body would require blood? Stomach. As the blood needs to flow there, your blood pressure goes a bit down after having had your meal. Brain is the same. Even you are not thinking, just looking at a wall, your mind being all blank, there is still a network working called default network.
There are different tools in functional neuroimaging where you can analyze the funciton of the brain and functional MRI (fMRI) is the most popular of them. Three articles are being published every single day where fMRI is used to understand the function of the brain in a given state or disorder. Amazing!
fMRI is based on the blood rushing into that part(s)/structure(s)/area(s) of the brain in a given function to supply more oxygen there. There will be more blood and oxygen in particular regions of the brain during the task you give to your subject. The principle is the blood flow is closely related to the neuron (the main cell of the nervous system) activity just like a relation between your leg muscles and the amount of blood goes there while you are running. The MRI gives signals based on the activation of the neuron relatively assessed by the increased blood flow. The subject in the MRI is asked to do a task. Let’s say he is memorizing some numbers. The numbers are shown, and after a while he is asked to repeat these numbers as much as he can remember. The brain regions related to the formation of long-term memory, encoding memory, etc. would be activated; you would find activation in the hippocampus. You can also quantify this activation relatively and compare a set of parameters between patients and healthy controls. The response time, the amount of activation, and most important of all, the regions activated or deactivated; relatively of course.
Structural MRI (Magnetic resonance imaging)
October 25, 2009
It was the August of 1997. I was doing my PhD at Department of Anatomy, Bursa, Turkey. It was a very hot day. I was reading some textbooks for my PhD dissertation topic. My brain was melting in my skull. It was like a beef steak in a pot burning. I decided to go the library where there is air-conditioner, and I would do some literature search as well. I do not know why I did that, but I entered the key words “anatomy” and “psychiatry”. Well, I had no idea what I was expecting to find. Wait a minute! There were some articles; particularly on schizophrenia. Here I was a happy camper at Anatomy Department teaching and learning anatomy, and there was my other passion psychiatry research which I had no idea on. It took me seconds to be back at the Department from the library. Since that day, for the last 12 years, I have been doing research on the anatomy of psychiatric disorders, particularly on mood disorders (i.e., major depression and bipolar disorder).
This is my story. But what is the story of “the anatomy of psychiatric disorders”? Here we go.
First of all, I can talk hours and hours on that, and I do promise to summarize everything in the following six paragraphs.
Wouldn’t it be nice to examine the brain of a person when the person is living? This question led into a big change in neuroscience. Before, it was an animal study, or a study during a brain operation, or post-mortem study (the brain of the deceased patient). But after the 80s with computerized tomography (CT) , and late 80s we see that brain researchers started to use magnetic resonance imaging (MRI); it was non-invasive and there was no radiation exposure; and most important of all a high quality of resolution compared to that of CT. As a result, we had the chance to see what was happening in the brains of patients with neurology and psychiatry, and neurosurgery while they were alive.
When I say structural MRI (magnetic resonance imaging; sMRI 1-2) I mean the quantitative measurements (mostly volume of any given brain structure) in the brain. We use this term very often, so I have left it as it is but you should know that it is about the brain. So you got the definition, right? Brain structures’ volumes (or very rarely areas ; particularly in the past just before 90s) are measured through MRI in a group of patients with a psychiatric (or neurological) disorder and at least age- and gender- matched healthy controls. We compare the volumes and see if there is any change; mostly decrease in that brain structure in the psychiatric patient group compared to a control group.
Structural MRI has the importance of detecting the affected structure in any psychiatric disorder. This was the first benefit from sMRI. For example, it is hippocampus for schizophrenia, it is amygdala for autism, etc.
The first question to be answered would be “is there any change in the size “volume” of that structure in the patient group. Second would be why. This comes to the famous question of quantitative MRI (another name for structural MRI) egg or chicken? So let’s say we are measuring the most famous structure to be measured in the brain “the hippocampus” on which I have spent 12 years. Hippocampus will be another post, but it is about memory and emotional regulation, so let’s say we are measuring it in depression (not surprising,no? considering its main functions). Hippocampal volume is decreased in patients with major depression compared to matched healthy controls. That is our finding.Ok? So are the patients depressed because they have smaller hippocampus or they have smaller hippocampus because of their depression. Here is a neat post from Dr. Kramer @ Psychology Today on that topic. You can ask this question in any psychiatric disorder.
Here in Canada, I have been working on a dataset where one of the main questions (maybe the main) was the effect of medication on these changes in the volume. Another question? Effect of genetics. Research is to ask the right questions after all. There are more questions you can ask through structural MRI, but it has been loosing its importance in the neuroimaging world since the beginning of 21st century.
Before I finish, I will answer the question: how are you measuring the volume of a brain structure on MRI? Let’s go back to history for that. Bonaventura Cavalieri was an Italian mathematician. He came up with the Cavalieri’s principle that set the rules of the scientific discipline; stereology. What is that? Simply it is used for measuring the volume of something from a two-dimensional environment; let’s say an image, a picture. I was at a stereology course in Samsun, Turkey in 1997. Let me give a simple example they gave us at the course. Take a cucumber. No, don’t eat it. We are going to measure it. Cut the cucumber in slices, with exactly the same slice thickness. Let’s say 1 cm. Now measure the area of each slice, and multiply it with your slice thickness, well you have an estimate volume of the cucumber. Of course, stereology is not all about this, but sMRI uses this principle of stereology. It is not difficult to explain what I am doing as a researcher when I am at a party. But, the difficult task is to define the brain structure of which I need to trace in each slice the structure is seen. When I say trace I mean drawing its boundaries with a specific program; our program was AFNI; a free program that runs in Linux. The program gives you the data you need when you are done tracing the structure so you get the volume. The boundary in the four directions (e.g., above, below) in a scan like this. Of course, your important task would be to decide in which slice I should start measuring and till which slice I should keep on measuring. Here is my volumetric measurement protocol of hippocampus on MRI.
Here is my very first structural MRI paper published in the first issue of Neuroanatomy.
Here is a more recent one titled ” A meta-analysis examining clinical predictors of
hippocampal volume in patients with major depressive disorder“
If you are a beginner, I recommend you to check the web pages of the big labs where they study the volumetric analysis of brain structures in psychiatric disorders or enter in PubMed; -the google of medical research- the keywords “MRI” “volume” “the brain structure you are interested in” and “the psychiatric disorder you are interested in”. And see what happens…
Below is a list of 19 big important players around the world who study structural MRI. The names are listed randomly.
Freiburg, Germany
Epilepsy; mood disorders, particularly major depression
Melbourne,Australia
Schizophrenia & mood disorders
Los Angeles, USA
Schizophrenia
Pennsylvania, USA
Schizophrenia
Detroit, USA
Schizophrenia
Stephen Lawrie (* a youtube video)
Edinburgh, Scotland
Schizophrenia
Iowa, USA
Schizophrenia
Utrecht, Netherlands
Schizophrenia
Detroit, USA
Aging
Montreal, Canada
Alzheimer’s Disease
Atlanta, USA
Major depression
Udine, Italy
Schizophrenia, mood disorders
Washington, USA
Major depression
Stanford, USA
Autism
Harvard, USA
Schizophrenia
Munchen, Germany
Major depression
NIMH (National Institute of Mental Health), Bethesda, USA
Major depression, bipolar disorder
Harvard, USA
Schizophrenia, bipolar disorder
Houston, USA
Major depression, bipolar disorder
The anatomy of romantic love
October 24, 2009
How many songs have been written so far on love and romance? How many poems? And how many movies have been made on the theme love and romance ? I know…What a silly question,no? Let me ask you something more sophisticated then..What is love?
Well, you asked for it & I have asked it. We are in 2009 (not in the romantic 18th century or late 60s), so let`s ask uncle google: “What is love?“. Here is the first link comes after entering the question:
`Love Quotations: “Love is...”
Here is an anonymous quote from that page “Love is like war: Easy to begin but hard to end.” As it explains love through war, it must be written by a Public Relations practitioner I am guessing, as they like explaining PR through war. 
Well, I am a Pisces: the king of romance in the astrology world. But I am a researcher as well. So let`s try to answer that question about the definition on love depending on the anatomical studies done on the living brain. Shall we?
First of all, which organ is the symbol of love? Heart. If you are a teenager, even an adult, you draw a heart; for wedding invitations for example. When we were teenagers, we used draw hearts at least. These days teenagers do not need to draw heart, they can text it to the loved one…Being a brain researcher, my sentence is “whatever the question is brain is the answer.“ Yes, when we are in love, adrenalin goes up, we get excited, palpitations and heart became the symbol. If love is in the air, however, it comes from the brain. The exceptional concept romantic love is not an exception.
If you have a technology where you can investigate the brain of a person when he or she is living (more to come in the fMRI post) then you can also see which brains are activated or deactivated relatively in people who are in love.We have several methods/techniques where we can image the living brain when it is functioning; the most popular one? Functional magnetic resonance imaging.
When you go back to the very first sentence of this post; your answer will be zillions..maybe..but there are not so many fMRI studies on romantic love. I am going to stick with these fMRI studies in this post.
How can you plan a study to get your answers about love? Practically, not so complicated. All you have to do is to make the lover go through his/her feeling process in the machine (i.e. MRI). So you find pictures of whose are not familiar with the person, and the pictures of the one who is being loved romantically by this person. Then you see which brain regions are activated in the case where they see the pictures of the persons they love, relatively. That structure gets activated, this gets activated, the other gets deactivated..all relatively.
Here is the fMRI literature on romantic love.
Of these regions; they belong to a circuit (let’s stay romantic and say circuit of love; (copyright me) and the researcher’s task is to interpret the activated regions and the circuit into function. I mean these regions belong to which known functions of the brain. Which functions do you think?TO BE CONTINUED
Till next time we meet here @ this post, I leave you with the last scene of the most famous movie on love.
