Annual Meeting Logo

Back some time ago I challenged readers of this blog to identify what it is that the logo of the SfN meeting represent.


THE ANSWER:  A Tyrosine Kinase Receptor (TRK)


Some members of this diverse family of receptors mediating the response to neurotrophic factors -  molecules that play important roles in determining the development and survival of neurons. The effects of neurotophins are chiefly mediated by TRK-A, TRK-B, and TRK-C receptors.


For example, Neuronal Growth Factor (NGF) is a neurotrophic factor that plays a role in promoting the survival of neurons through the TRK-A receptor.  Interestingly,  NGF can also bind p75 receptors  - a member of the Tumor Necrosis Factor (TNF) family of receptors.

Examine the SfN logo again.  One of the interesting aspects of the TRK family or receptors is that when their ligand (e.g., NGF) is bound to the receptor, they form functional dimers - two paired receptor components.  The function of the activated dimer-receptor complex  is determined by the pair of components that form the dimer.  There can be functional homo-dimers as well as functional hetero-dimers (two similar components or two different components, respectively). An example is p75/TRK-A dimers which are functionally more responsive to NGF than TRK-A homo-dimers (Baker, 2004), .

Another neurotophin, Brain Derived Neurotrophic Factor (BDNF), exerts its influence via the TRK-B receptors.   Chronic stress decreases BDNF production which has been implicated in several neurodegenerative disorders and some psychiatric conditions that are characterized by regionally selective neuronal degeneration such as chronic depression and Post Traumatic Stress Disorder (e.g., Dell'Osso, L. et al, 2009) .

 


For more on BDNF and TRK receptors and depression, you can peruse another blogger's post by following this link, or you can read the review by Nobel et al (2011) - Caution:  the content is comprehensive and advanced).

Cited Sources

• Baker, P.A. (2004).  p75NTR is positively promiscuous: Novel partners and new insights. Neuron, 42 (4), 529-533. doi:10.1016/j.neuron.2004.04.001
• Dell'Osso, L. et al. (2009). Brain-derived neurotrophic factor plasma levels in patients suffering from post-traumatic stress disorder. Progress in Neuro-Psychopharmacology & Biological Psychiatry, 33, 899-902. doi:10.1016/j.pnpbp.2009.04.018
• Nobel, E.E. et al. (2011). The lighter side of BDNF. American Journal of Physiology: Regulatory and Integrative Comparative Physiology, 300 (5), R1053-R1069. doi: 10.1152/ajpregu.00776.2010

FUN Poster Session & Social

Monday night  I attended  the annual poster session and social event sponsored by the Faculty for Undergraduate Neuroscience (FUN). Over the past decade the event has grown to be one of the largest of the socials sponsored by the Society for Neuroscience.  There were 165 scientific poster presentations by undergraduates at the social. 

For students, FUN provides competitive travel awards that assist by covering some expenses for undergraduates presenting their research at the conference.  This year there were 16 travel award recipients.  It is also a great opportunity for undergraduates to speak with representatives of graduate programs in neuroscience and for faculty to re-connect with their former students who are now pursuing careers in the neurosciences.  

A number of awards are announced at the FUN social, among these were the Educator of the Year Award, which was awarded to Patsy Dickinson of Bowdoin College (ME), and the Lifetime Achievement Award, presented to Stephen George of Amherst College (MA).

Another important announcement was that The Journal of Undergraduate Neuroscience Education (JUNE) - an open-access, peer-reviewed journal, edited by FUN members - will be listed on PubMed.  The most recent issue of JUNE was just posted on the journal's website: http://www.funjournal.org/  In fact, I have an article on design and assessment of undergraduate neuroscience curricula that is co-authored with colleagues at Ithaca and Oberlin College.

Following the FUN social Nikki Scutella ('10) and I walked a few blocks to enjoy a memorable dinner and get re-acquainted.  Nikki is currently a research assistant in a laboratory of Dr. Gary Fiskum at the University of Maryland Medical College. 

What does the SFN Conference Logo Represent?

Prior to the SfN conference I challenged readers to try and identify what it is that is represented in the SfN Conference Logo.   Tomorrow I'll post the answer.So there is still time to submit your answer as a comment to this post.

Here are some hints:

• It is found in the cell membrane of some neurons.
• It has a ligand binding site - a site where chemical messengers (e.g., neurotransmitters) can bind.
• It is NOT an ionotropic receptor complex

SOMAS Luncheon @ SfN

It was a great privilege to attend the 2012 SOMAS Luncheon at the annual SfN meeting yesterday.  This is a great program that has supported undergraduate neuroscience instructors in the early stages of their careers and provided funding in support of the collaborative student-faculty research.

The 2012 SOMAS award winners and their students are:

• Carlita Favero, Ph.D.  Ursinus College
• Elizabeth Glater, Ph.D.  Harvey Mudd College
• Josef G. Trapani, Ph.D.  Amherst College
• Charles Weaver, Ph.D.  Saginaw Valley State University
• Sarah Webster, Ph.D.  College of the Holy Cross

You can learn more about their projects at the SOMAS website: http://www.somasprogram.org/

The Brain on Idle

Sophisticated and highly technical functional brain imaging techniques such as fMRI and PET have revolutionized the cognitive and behavioral neurosciences.  These techniques offer a valuable non-invasive means for visualizing, localizing, and quantifying patterns of brain activity.  But a recent essay in the journal Nature focuses on what might be the important functions of the baseline brain activity that occurs when subjects in these scanners are instructed to "clear your mind".  In such instances brain activity diminishes by just a 1-5%. Some investigators believe that there is much to be learned from examining the resulting patterns in activity in the idling brain (mind). Here are some suggestions that are presented by the essays author,  Kerri Smith:

• idling brain activity may keep essential neural pathways interconnected.
• the activity may be necessary to prime the brain for action
• it might be performing essential "off-line" functions related to such processes as memory consolidation.
• it may even be that this activity may be "meaningless" - e.g., fMRI actually measures patterns of regional blood flow, not neural activity itself.

However, according to Smith, there is general agreement among most investigators that these are mere guesses (hypotheses).  What is more, it is not clear how to devise experiments to test these alternative hypotheses.

Here are some other facts that are shared in the essay:

• patterns of intrinsic brain activity differ in distinctive ways between healthy controls and individuals with various brain disorders such as Alzheimer Disease and Autism.
• distinctive patterns of intrinsic brain activity at any instant might predispose individuals to respond to ambiguous situations or stimuli. 

To illustrate the latter point, Smith summarizes the result of a study (Hesselmann et al., 2008) that is somewhat similar to another I learned about in a recent presentation at the College by Bill Klemm of Texas A&M.  Hesselmann et al.  compared the intrinsic patterns of brain activity in subjects just before they were presented with some classic ambiguous visual stimuli.  When presented with such stimuli subjects might perceive either the image of a face or some other image such as a vase or a reclining woman. According to Klemm what a particular individual is more likely to see initially is relatively constant from one trial to the next – the perception that an individual experiences first tend to be  reliably consistent.  Another way to say this is that is seems that their brain is prepared (possibly biased) toward perceptions of a particular nature.  And in the study by Hesselmann et al. the intrinsic pattern of activity observed in those participants who initially perceive a face was characterized by enhanced activity with a region that is known to play a role in facial perception - the fusiform face area (FFA).  The intrinsic activity of their brian just before the stimulus presentation apparently influenced their perceptions.

Are you prepared to step on your accelerator?  What hypotheses might you have for the function of intrinsic brain activity?  Do you anticipate that such intrinsic activity should resemble activity during mediation or sleep? Please share your hypotheses or ideas for how experiments might be performed to test some hypothesis presented above.

Sources Cited

• Hesselmann, G. et al. (2008). Spontaneous local variations in ongoing neural activity bias perceptual decisions.  Proceedings of the National Academy of Sciences: USA,  105 (31) 10984-10989. doi:10.1073/pnas.0712043105
• Klemm WR, et al. (2000). Coherent EEG indicators of cognitive binding during ambiguous figure tasks. Conscious Cognition 9 (1):66-85.
• Smith, K. (2012). Idle minds.  Nature, 489 (7416), 356-358.

You can listen to a podcast related to this topics here:

Chuck Close - My Life as a Rolling Neurological Clinic

So what did Close have to share in his public presentation?  

Due to health issues that left Close unable to travel, he appeared via a satellite link from his studio in NYC.   For the first half-hour he shared with us the events and circumstances in his life that shaped his art.  Among these were, poverty his family experienced, the early death of his father, the influence of his grandmother who herself was housebound by agoraphobia, his great difficulty recognizing faces, his learning disabilities, the mid-career collapse of a spinal artery that left him unable to move below his chest  and how it was that art had ultimately "saved his life".   How had art done this?  Because despite what appeared to be limitations, art allowed him to demonstrate that he still had something he could contribute.  There has been something about the accomplishments that Close has attained that has transcended his physical abilities. 

To me what this may illustrate is just how much will remain to be explained by neuroscience even if we ultimately reach a complete understanding of the biological workings of the brain.  While I am usually more comfortable in my own research working from the assumptions of a biological reductionist, the alternative explanations remain both a challenge and an inspiration for pursuing research in the behavioral and neural sciences.  

In my view, there remains no greater challenge in science than to pursue an understanding of brain function.   Yet even should we obtain such an understanding, what might ultimately remain unfathomable will surely be inspiration for the efforts of future neuroscientists.  To be a scientists is inevitably to recognize that each answer that is achieved results in an innumerable number of questions that you've likely to have never contemplated. As Close shared, the process of constructing each of his portraits was often more rewarding than the product.  Another way of expressing this is that the journey is somehow more enlightening than reaching your destination. In my experience, this is almost always the case.

To enhance his journey, at each new phase of Close's career he challenge himself to embark upon a new approach to portraiture - remove color, add it back, add elements ("incremental units") within either a horizontal, diagonal or radial grid.  In each instance, the challenge that Close set for himself seemed to me to be much like the challenge before each chemists, physicist or neuroscientist.  That challenge is to understand how such incremental units (e.g., each, element, subatomic particle or neuron), which in isolation may seem rather simple, can collectively contribute to something much greater.  

There is also something inspiring to me, and I hope to my students, about how the collective contributions of a single neuroscientist may ultimately result in achieving a much more comprehensive understanding of the brain and mind than would otherwise be attainable.  Today the total number of registrants attending the SfN conference reached nearly 28,000.  By the end of the conference that number will probably exceed 30,000.  That is very encouraging.

Lastly, there are a few things Close shared that piqued my curiosity.  For example, he described his face-blindness  as a difficulty recognizing three-dementional faces.  It was much easier for him to work from two-dimensional photographs of his subjects than the subjects themselves.  One of the great quandaries in neuroscience is the Binding Problem -- i.e., how is it that features (elements) that are represented in disparate regions or neural circuits are somehow combined to create a perceptual unity, e.g., a unique facial percept.

I wonder if there have been any studies that might indicate that face-blindness might arise in some instances from a deficit in a circuit that is responsible for binding "flat" incremental facial features into a three-dimensional facial percept.  Anyone out there know if their is any evidence of this in the neuroscience literature? Notably, most studies of prosopagnosia employ two-deimensional "flat" facial stimuli.  Might this mean that the incidence of face-blindness is even more common than is estimated?

Katrina's Aftermath

For several years the SfN Meeting was held between venues in DC, Florida, St Louis, Los Angeles/San Diego, and New Orleans.   In 197, 2000 and again in 2003 the meeting was to be held in New Orleans.  Katrina changed that. The views you see here describe the path of the hurricane, a view of the populace that sought refuge at the Convention Center and  view from the air of the flooding around the Super-dome which is within a mile of the convention center. 

The 2006 and 2009 meetings were scheduled to return to NO, but the 2005 hurricane caused the society to cancel those plans.The 2012 meeting is the first time that the meeting returns to New Orleans.  It seemed ironic that just a few month ago, NO was under threat of another disaster from hurricane Isaac.

My first impressions upon returning....

Keep in mind that my impressions thus far are limited only to the things I've been able to observe from my arrival yesterday afternoon until this morning.   From what I've seen and done thus far, things seem much the same.  There is a great deal of construction/re-construction that appears to still be going on.  The people I've met so far seem extremely friendly and are very glad that there are visitors form out of town.  The local news last night featured a story on people who were still displaced from their homes by Isaac - an hurricane season is not over.  But for this week, the forecast is for sunny days and mild nights.  I'll add more to this post throughout my visit.  

Mysteries of the Brain

In conjunction with the SfN meeting, the journal Science has published a special issue with featured articles on various “Mysteries of the Brain” and on Chronic Depression.  Here is an opportunity to determine the content of one of my posts on this blog.  Please let me know which of the following articles you would like me to feature in the blog. The majority of request I receive via comments prior to Saturday, October 13 will determine what I’ll post in the blog.   Here are the choices: 

• Why is mental illness so hard to treat?
• Why are our brains so big?
• Why are you and your brain unique?
• Can we make our brains more plastic?
  •  

2012 MacArthur "Genius" Award Recipients

Nope....  I'm not one of them.  But among the 22 recipients of the $500,000 awards in this year's class of MacArthur Fellows there are two neuroscientists.  

Elissa Hallem, Ph.D.
Arguably, the least well understood of our sensory/perceptual systems is the olfactory system. However, over the past two decades there have been significant advances in our understanding of how odors are represented within the nervous system.  Hallem's approach is to employ is to learn how this is accomplished in relatively simple nervous systems - those of the fruit-fly and the nematode. While these are relatively simple nervous systems compared to our own, the skills required to do this type of work are extremely complex and technically demanding.  Understanding how olfactory cues are processed in these simple organisms provides important insights into our own olfactory system. Hallem's research has important applications as the focus is to examine how mosquitoes an parasitic nematodes employ chemical signals to locate their hosts (that could be you, me, our pets or the animals that we depend upon as sources of food). You can learn more about her work by clicking  here, and reading the articles below:

Fluorescently labeled nervous system of the nematode c. elegans

• Hallem E.A. et al. (2011) A sensory code for host seeking in parasitic nematodes. Current Biology, 21(5), 377-83. DOI 10.1016/j.cub.2011.01.048
• Hallem, E.A. et al. (2011) Receptor-type guanylate cyclase is required for carbon dioxide sensation by Caenorhabditis elegans. Proceedings of the National Academy of Sciences: USA, 108(1), 254-259. 

Benjamin Warf, M.D.
Warf is a Pediatric Neurosurgeon, a specialist in pioneering techniques for treating congenital malformation of the CNS, specifically  hydrocephalus (HC) and spina bifida. The typical surgical approach to treating HC is to place one end of a shunt (tube) within the cerebral ventricals of the brain and the other end within the abdominal cavity.  Excessive cerebral spinal fluid (CSF) that would accumulate within the ventricles, compress the developing brain and in young children cause an enlarged head is diverted by the shunt into the body cavity where it is reabsorbed.  However, these shunts often fail, requiring additional surgeries.  Warf developed an alternative approach in which the fine capillaries (choroid plexus) within the ventricles that are the source of CSF are cauterized, thereby reducing the accumulation of CSF within the ventricles.  His work has had significant impact in developing countries such as Uganda, where he established a hospital and a program to train surgeons in the treatment of CF.   You can learn more about his work by clicking  here, and by reading the articles listed below.

• Warf, B.C. (2012) Long-term outcome for endoscopic third ventriculostomy alone or in combination with choroid plexus cauterization for congenital aqueductal stenosis in African infants. Journal of Neurosurgy: Pediatrics, 10 (2), 108-11.

Chuck Close

Each year the Society for Neuroscience host a special talk by an individual who is not a neuroscientist, but whose work has contributed to a greater understanding of neuroscience among the general public.  This year that person is the artist Chuck Close.

Anyone who is interested in art, aesthetics, perception,  and their relationship to the brain and mind should find something to appreciate in the life and work of Close.  

One of the things I find intriguing is that while his career was established through the remarkable style of his portraitures, Close has been diagnosed with prosopagnosia - or "face blindness". Individuals with prosopagnosia have difficulty identifying others solely by the appearance of the face and in extreme cases may not even recognize their own reflection in a mirror.  While such extreme cases often result from strokes that damage an area of the brain called the fusiform face area (FFA), neuroscientists now recognize that the majority of cases are more mild and are congenital. Close attributes his interest in portraiture to this disability - it emerged as a sort of coping mechanism.