December 04, 2008

Scientists Explore the Neuroanatomy of Depression

In an article in the November issue of the Journal of Neuroscience researchers Michael Koenigs, Edward D. Huey, Matthew Calamia, Vanessa Raymont, Daniel Tranel, and Jordan Grafman submitted an article entitled “Distinct Regions of Prefrontal Cortex Mediate Resistance and Vulnerability to Depression?. The study looked at the anatomy of the prefrontal cortex and discovered the different influences certain sub regions have on depression.

The study started from analysis of brain images of a “depressed brain?, that is a brain of a person with some kind of depression disorder. This analysis led researchers to the conclusion that there are abnormal patterns of activity in the prefrontal cortex of the depressed brain. It has long been known that the prefrontal cortex is associated with personality and mood and therefore mood disorders, but study of specific sub nuclei has been limited.

In this particular paper Koenigs et al. looked at patients with brain lesions (damage to specific parts of the brain). They focused on subjects with lesions in the ventromedial prefrontal cortex (vmPFC) and the dorsolateral prefrontal cortex (dlPFC), two sections that showed particularly abnormal behavior on the brain scan. The images below show the location of the vmPFC and the dlPFC in the human brain. The first image shows the vmPFC highlighted in pink and the second image shows the dlPFC in green.

source: Wikipedia.com

source: Google Images

The subjects with damage to the vmPFC were significantly less likely to have depression. This shows that vmPFC likely plays a strong role in the susceptibility of one becoming depressed, on the other hand a damaged dlPFC increased the likelihood of having depression in turn showing that the dlPFC could be involved in resistance to depression.

While these findings may seem minor at first look in reality they are hugely beneficial to the understanding and future research on depression. There are many factors involved in depression, so much so that the research can be overwhelming. However, by specifying two sub regions that play dramatic roles in the disorder researchers can focus their study and attempt to develop more complex studies to understand what goes wrong in these regions causing depression. Future studies will focus on these regions and what can be done to change the abnormalities in order to treat and possibly prevent depression.

Posted by horr at 03:06 AM

December 02, 2008

Schizophrenia

This blog will focus on a slightly different subject than my past entries but will still focus on the most recent developments in Neuroscience research. Schizophrenia, which literally means “split mind?, is a brain disorder characterized by disorganized thoughts and in many cases hallucinations and delusions. One of the horrifying parts of schizophrenia is the late and sudden onset of the disease. The neurological factors of Schizophrenia are largely unknown to scientists and early detection for the disorder is difficult. Schizophrenia onset is usually in the early twenties and can occur in a variety of fashions. Some forms of Schizophrenia can be successfully treated allowing a person to live a normal life, however, there are forms that even with treatment leave the patient debilitated and ostracized from the public.

Recently a study was published successfully locating a brain malfunction that causes Schizophrenia. The article is called “NIH Scientists Identify Link Between Brain Systems Implicated in Schizophrenia? and was conducted by Andres Buonanno, Ph.D. and colleagues at the Eunice Kennedy Shriver National Institute of Child Health and Human Development, a NIH lab. Three distinct brain areas are believed to be a part in Schizophrenia, this study looked at the relationships between the three areas and how a breakdown in the communication between brain areas could be to blame for Schizophrenia. More specifically, researchers believe that a malfunction in the intermediary circuit linking between the three brain circuits could be the culprit.

One of the three systems is the glutamatergic system. This system is involved in long-term memory. The researchers discovered that a molecule called Neuregulin-1 controls the release of Dopamine, Dopamine in turn controls brain electrical activity levels in the glutametergic system. Dopmine can have a myriad of effects in the body and based on what receptor in binds to can have profoundly different effects on memory. It is now believed that an imbalance of Dopamine binding and the effects that has on the glutametergic system could be one cause of Schizophrenia.


source: Google images
The above depicts a Dopamine molecule binding to a receptor. Depending on what type of receptor Dopamine can have dramatically different effects including storing long term memories and even erasing existing memories. The binding of Dopamine to receptors is an important part of the glutamatergic system, on of the three systems now believed to be linked in the cause of Schizophrenia.


This research is a huge break in the understanding of Schizophrenia and is based on the research of many parties. The hope is that with this new information regarding the origins of the disorder newer and more efficient treatments can be developed. Current Schizophrenia treatments focus on blocking Dopamine receptors; however, newer treatments could focus on the Neuregulin-1 molecule or the glutamatergic system. These treatments would be more effective and potentially have fewer side effects then current treatments.

Posted by horr at 07:28 PM

November 30, 2008

The Journal of Neuroscience

The Journal of Neuroscience is a weekly publication developed and run by the Society for Neuroscience. It is meant to keep all members of the society up to date on current research practices as well as announce the latest developments in the field. Membership to SfN comes with a subscription to Neuroscience.

In the most recent issue there was an article titled “The Role of Neuropeptide Y in the Expression and Extinction of Fear-Potentiated Startle?. The article was written by Alisa R. Gutman, Yong Yang, Kerry J. Ressler, and Michael Davis and focused on the role Neuropeptide Y has conditioned fear. The researchers discovered that this specific neuropeptide could eliminate a certain conditioned fear while a “antagonist form? of the neuropeptide could stop that fear from ever being eliminated. This shows the Neuropeptide Y in fact plays a crucial role in conditioned fear.

A neuropeptide is just a specific name for any peptide found in the neural tissue. Peptides are just one of the chemical signals the body uses to communicate throughout the body. Peptides are most commonly know for their role in making proteins but they can take many other forms. Neuropeptide Y in particular works with the neurotransmitter Norepinephrine. Norepinephrine is a stress hormone that plays a key role in understanding anxiety.

The results of this study are exciting to the world of cognitive and behavioral research. Being able to isolate and understand the effects this neuropetide has on fear will open the doors to more research and more discoveries. Additionally, the understanding of the role Neuropeptide Y plays in conditioned fears can help for the development of treatments for the many people afflicted with conditioned and often irrational fears.

Below is a picture of the structure of the Neuropeptide Y.


Source: google images

Posted by horr at 11:30 AM | Comments (0)

November 24, 2008

The Society for Neuroscience

Researchers from tenured professors to undergraduate students all over the world are a part of the Society for Neuroscience (SfN) . The SfN sends out a monthly newsletter that allows members to stay on the cutting edge of Neuroscience research developments. This newsletter includes recently published articles and upcoming conference events and details.

The mission of the society is to advance the understanding of the brain and nervous system, provide career development opportunities for research professionals, and to promote understanding and information to the general public.

One of the career development opportunities SfN provides is its annual conference. This conference incorporates thousands of poster sessions with guest speakers and even opportunities for technical development companies to sell their newest products. This years Neuroscience 2008 was hosted in Washington D.C. and had over 31,000 attendees.

This year was my first opportunity to experience the Neuroscience conference. I had heard about it since the beginning of my time in the lab. When I first walked into the convention center it was a bit overwhelming. I couldn’t help but feel out of place, especially being a business major instead of Neuroscience or pre-med of some kind. However, as I walked around I realized that this conference is like the world series of research conferences. Everyone is there and buzzing with excitement. At lab dinners all my coworkers would reminisce about their first conference or the most exciting symposia they had been to. I watched as old colleagues caught up and showed off their new positions or lab credentials. As different an experience as it was, it was exciting. I finally got to participate in an event everyone at work looks forward to year round. And I understand why now. It’s a bit of a rush giving a presentation and spotting in the crowd a professor whose research papers you have studied or whose experiments you have attempted to re-create for months.

The Neuroscience conference provides not only an amazing experience for professionals to network with one another or exchange ideas, but it also provides an opportunity for old colleagues to catch up or young researchers to meet the founders of their field.

Posted by horr at 04:18 PM

November 22, 2008

The HR/LR Model

To start of my blog I’ll give a little background on my own research and the research done at MBNI. My research has focused primarily on the HR/LR model and its uses as a novel rodent model for depression. When I started last September I was introduced to the HR/LR model. The model is based off of loco motor scored in a novel environment, in other words the rat is placed in a new cage and its movement is monitored. In a litter of normal purchased lab rats some show naturally higher loco scores that others. In our original round of breeding we divide these into the high scoring or High Responder (HR) and low scoring or Low Responder (LR) groups. From there HRs are bred with HRs and LRs with LRs etc. As generations pass of these selectively bred animals their loco motor responses become more defined with the LRs consistently more lethargic and the HRs more hyperactive.

Along with these loco characteristics come characteristics involving depression and anxiety. LRs show consistently higher depression scores and anxiety scores while HRs show significantly lower. While it is often hard to determine what makes a rat “depressed? or “anxious? there are several accepted tests that can be markers for these characteristics.

The first is called the Forced Swim Test (FST). In this a bucket is filled with water and the rat is placed in it for 15 minutes. The rat can either float, swim, or climb at the sides, after 15 minutes the rat realizes that it can’t escape, this is a term in psychology referred to as learned helplessness. After the 15 minutes the rats are removed and put back in their cages. 24 hours later the test is run again, but this time only for five minutes. The sign of depression is having significantly more time spent floating or immobile than is spent swimming or climbing. LRs show significantly higher immobility times compared to their HR counterparts.

The second test is called the Open Field Test (OF). In this the rats are placed in a large, typically about three feet by three feet box. Rats are nocturnal animals and generally prefer to stay in dark areas. This is a test of anxiety and it measures the latency of the animal to enter the open center of the box and the total amount of movement. The LRs show increased anxiety and stay primarily in the darkest corners of the box while the HRs enter the center of the box more quickly and are more likely to stay in the center.

The third test is called the Elevated Plus Maze (EPM). In this there is a cross shaped maze that is raised off the ground by about five feet. Two of the arms are enclosed while the other two are open. Much the same as the OF test the EPM tests anxiety by measuring the latency to enter the open arms and the amount of time spent in the open arms. As is to be expected the LRs spend most of their time in the closed arms while HRs are more willing to explore the open arms.

Recently we have decided to test how good a model for depression the HR/LR model really is. We treated HRs and LRs with a common anti-depressant called Paroxatine. With the anti-depressant treatment we found that we were able to significantly decrease the depression characteristics in our LRs. From this we concluded that in fact we had developed a novel model of depression.

Posted by horr at 11:13 PM

November 18, 2008

Welcome Entry

My blog is about research and advancements in the Neuroscience fields. For the past year and a half I’ve been a Research Assistant for the University of Michigan ‘s Molecular and Behavioral Neuroscience Institute (MBNI) http://www.mbni.med.umich.edu/mbni/index.html. My research focuses primarily on depression and hyperactivity disorders. We use a novel rodent model for depression and hyperactivity known as the HR/LR strain of rats that has been developed by our lab over the past years. These rats have been selectively bred based on accepted markers for depression and anxiety.

Through the selective breeding process we have created the High Responding (HR) line that exhibit lower than normal anxiety markers and higher loco motor scores, and the Low Responding (LR) line that exhibit higher scores on tests for depression and anxiety. They also have significantly decreased loco motor scores compared to the HRs. We use this model to explore the behavioral and neurobiological differences involved in depression and hyperactivity.

The Society for Neuroscience (SfN) recently hosted their annual meeting in Washington D.C. This conference draws neuroscience researchers from undergraduate students to the leaders and most respected professionals in the field to present their recent findings and exchange ideas. U of Ms MBNI sent many presenters including myself. The conference allowed me the opportunity to see how vast a field neuroscience really is and how much research is being done to understand the brain.

Through this blog I hope to convey some of the cutting edge research that is being done in the field today. I will discuss presentations given at the SfN conference and also articles found in the news regarding the newest developments and discoveries in neuroscience research.

Posted by horr at 03:39 PM