January 26, 2012
2011 Society for Neuroscience Conference Highlights
Time: 00:09:09 | Size: 8.40 MB
Speaker: NIMH Radio
Description: NIMH Radio: The 2011 Society for Neuroscience Conference was held in Washington, DC.
Announcer: NIMH Radio, from Bethesda.
Announcer: The annual meeting of the Society for Neuroscience, which took place in 2011 in Washington, is now perhaps the most important single meeting for the spectrum of disorders of interest to NIMH. These include schizophrenia, anxiety and mood disorders, and developmental disorders, including ADHD and autism. The Society for Neuroscience has become the place to go for research on these disorders because of the increasing realization that they can be studied as brain disorders, especially disorders of brain circuits. Judging from the attendance at this year’s meeting — over 32,000, most of them neuroscientists — there is little doubt that the field of neuroscience is thriving and providing insights that will transform our ability to prevent and treat these disorders. This year’s meeting was five days of lectures, symposia, and posters about every facet of the nervous system. Every year, particular themes emerge and a lot of what went on at this year’s meeting concerned the connectome—the wiring diagram, the map of connections, of the brain. The connectional anatomy and development of brain circuits is very much the core basis, the intellectual and scientific foundation, of how we are beginning to think about these neuropsychiatric illnesses. National Institute of Mental Health Director, Dr. Thomas Insel...
Dr. Thomas Insel: Because we also think about these disorders as developmental, a lot of what happens at this meeting revolves for us around developmental neuroscience. The key for us is learning how genetics and environment lead to the development of circuits, that’s really the way they get laid down and connected, and, finally, how these factors bias the system in the way that information is processed in the brain. We think about these processes as being ultimately what leads to a risk for any of the illnesses that are key for NIMH. Therefore it’s really not too surprising that this year, another recurring theme at the meeting was epigenetics — epigenetics are the heritable differences in gene expression that are not the result of DNA sequence. Many presentations here reported evidence of how experience may be encrypted in epigenetic changes than can be transmitted, and can alter behavior, sometimes actually over generations. This work has important implications, not only for understanding complex interactions between environment and genes — but for understanding the contributing roles of both in how environment and genes together effect disorders of mental health.
Announcer: It’s impossible to cover every aspect of such a large and diverse meeting in a brief overview. To provide an example of the research presented there, one area in which some particularly interesting work was presented was the impact of stress on the brain and behavior. It might seem self-evident that stress can contribute to anxiety and depression, but researchers want to know the exact mechanism by which stress has its effects on behavior, and why it appears that stress can sometimes alter behavior not just in individuals, but across generations. Several NIMH-supported investigators discussed their work on stress: Here, for example, Michael Baratta from MIT describes the use of an innovative approach called optogenetics to investigate the effects of stress on fear learning.
Dr. Michael Baratta: So, trying to figure out how the brain couples prior stressful experiences with ongoing learning is one of the major challenges facing neuroscience. Say on the battlefield presented with a lot of cues that could predict that something dangerous is in the environment. Those same cues can predict something completely different when they’re back, when a soldier is back in a hometown. That ability to regulate or adapt your behavior to your context is very critical to survival. Understanding how stress influences your ability to adapt to that context and respond to appropriate cues is very important from a psychiatric perspective. So what we did is we take an innovative approach. We took light responsive proteins from bacteria and we packaged them in a virus so that we could deliver them into very specific cell populations in the brain now making those cells light responsive. This is very cool because it allows us to manipulate the activity of these cells by turning them on, turning them off on very fast time scales. In fact these are time scales that are relevant to the features in our environment that we use to guide our ongoing learning. What we found that was sort of surprising was that serotonin didn’t play a role in normal fear learning per se but what it did do is block the stress enhancement of that fear response to the tone, which suggests that serotonin is not playing a role in fear learning but is actually tuning the strength of that memory to produce an exaggerated fear response. One thing that scientists are finding is that individuals with post traumatic stress disorder have a hard time extinguishing these fear responses... This may be a hallmark of post traumatic stress disorder and if we understand better then we can develop new target treatments that can develop target treatments for it.
Announcer: Other scientists are investigating how stress in a parent can have lasting effects on the behavior of offspring. Here, David Dietz of the Mt. Sinai School of Medicine in New York talks about the work he presented at the meeting on the effects of stress across generations.
Dr. David Dietz: Major depression is a terrible disease that affects millions of people. From statistics in humans it appears that a large majority of cause of major depression appears to be through some genetic mechanism. That is to say that if your parents are depressed, there seems to be some correlation to the offspring, to their children and future generations also becoming depressed. That being said, we have a nice model of stress and depression in our laboratory — social defeat stress. And so basically we wanted to ask the question is can we model some of this transmission through different generations using our model. So the way social defeat works is that we take normal laboratory mice and expose them to an aggressive male in his cage, and he’s repetitively and chronically exposed to these aggressive mice over a period of 10 days. What’s been shown before is that these mice present with a phenotype that is very similar to human depression And we were actually interested in the question of whether or not — because the social defeat model uses all male — whether or not we could we pass on a depressive-like behavior from a paternal line. So that is, do the fathers pass on their susceptibility to the offspring. Well we mated them and then we examined whether or not the offspring, the females or males of these fathers, also showed a susceptibility to depression. And indeed that’s what we found. To make sure that the fathers weren’t doing something to the pups themselves, the fathers were removed from cages long before the pups were ever born. As I said I think the big take home message is that environment plays big role in how your offspring — even if you have a depression or some illness of this sort that behavior may play a big role in how their offspring may fare. I think it’s important to understand also that environment is a bigger thing than just interaction directly.
Announcer: The research of Drs. Baratta and Dietz are two brief examples of the work presented on stress at November’s meeting. These findings barely scratch the surface of what was an extraordinary week of exciting science on the brain and behavior. With continued support, neuroscience will continue to generate advances like these, and deepen our understanding of mental health and disease.