Recent Lab News
Andrew Young: Best Neuroscience Graduate Award (UW Neuroscience program).
Jonathan Musser: Flyod Clark Fellowhsip Award (UW, department of Zoology and Physiology).
Tyler Felton: NSF EPSCORE summer, spring and fall fellowship (three consecutive awards!).
Sun lab team' Research and Destroy' won the 'March Madeness Basketball Competition Championship"
Andrew Young: Annula Frong Range Neuroscience Conference Selected Student's Oral Presentation entitled" GABAergic Inhibitory Circuits of the Posterior Piriform Cortex of the GAD67-- GFP Mouse" (Fort Collins, CO)
New Study Contributes to the Understanding of Olfactory Microcircuits.
Continuing their research in the olfactory cortex of mice, Dr. Qian-Quan Sun and his graduate student, Andrew Young, have made significant progress towards unraveling the complex cellular properties of this little understood brain region. Using live brain sections, Young and Sun probed the unique electrical and anatomical properties of a select subset of cells genetically marked with a fluorescent jellyfish protein, allowing for direct visualization of cells that would otherwise be lost in the crowd of neurons found within the brain. These particular inhibitory cells are poised to influence numerous aspects related to how the brain processes incoming olfactory signals from the environment, yet until this time the properties of these cells were unknown. Their results indicate 5 distinct cell types based upon the inherent active and passive electrical properties of the cells. Each of these cell types displays a unique location within the brain, providing evidence towards their functional roles. In addition, each cell type had axons and dendrites with marked intergroup anatomical differences, lending support to the functional diversity of these cells and providing a useful marker for group identification. Examining the expression of various marker proteins, they found further evidence that these 5 cell types were indeed distinct from one another. For the first time, they have correlated the electrical, anatomical and molecular properties of a diverse suite of inhibitory neurons within the olfactory cortex, placed these cells into relevant groups, and emerged with a more detailed map of this particular brain circuitry. Combined with their previous research, a far greater understanding of the key cellular components involved in olfactory processing at the level of the cortex has emerged. This research provides both a fascinating look at the specific properties of a complicated brain circuit and a necessary foundation for future work within the olfactory cortex that intends to examine its intrinsic circuitry, and ultimately, to clarify its functional properties.
New Study Contributes to the Understanding of Olfactory Learning.
In a recent study, Dr. Qian-Quan Sun, an assistant professor in the department of Zoology and Physiology and his graduate student, Andrew Young, uncovered unique properties in the olfactory center of the brain designed to encode incoming odorant information from the environment. Using methods to electrically stimulate the olfactory cortex in mouse brain, Sun and Young produced long term reductions in the strength of olfactory signals to other brain regions, specifically those regions involved in memory, emotion and conscious thought. Additionally, drugs designed to target specific receptors located in the olfactory cortex can either mimic or block these long lasting changes, indicating a specific mechanism of action. This discovery provides important evidence relating to mammals’ ability to quickly adapt, or habituate to odors present in their surroundings, and provides insights into possible strategies the brain utilizes to pair these odors with specific behaviors.
On August 14th, the lab went on a hiking trip to snowy range -medicine-bow national forest. We started out at Libby Lake with an elevation of 11,000 ft. Going uphill was very challenging! We reached the Medicine Bow Peak (elevation 12,013 ft) in ~2 hours. The senary was vast and meganificent. (Reported by A hiker).
Download the hiking movie (in pdf formate)
Finding the Cause Can Lead to a Cure Epilepsy
Qian-Quan Sun, assistant professor of zoology and physiology and a researcher on the neuroscience center grant, is studying how neural circuits develop in the brain. These circuits carry information to and from the different parts of the brain and body.
When looking at brain tissue under a microscope, Sun says it is difficult to see neural pathways. So Sun infuses genetically engineered mice with fluorescent jellyfish proteins that make the neural pathways glow. “We breed these mice, and their offspring have color-enriched brains,” Sun says.
Sun says he sees similarities between neural growth in human and mouse brain development, though during differing lengths of time. He says a 17-day-old mouse’s neural development corresponds roughly to neural growth in a one- to two-month-old human. That comparison can be useful when projecting results of experiments with mice to possible outcomes in humans.
Sun has learned that the growth of neural pathways is regulated by genetic programming and is enhanced—or retarded—by experience or trauma. An experiment on how a mouse’s whiskers transmit information to the brain in early developmental stages proved this theory. Whiskers are a mouse’s apparatus for sensing touch and spatial perspective. Sun and researchers mapped each area of the brain corresponding to a specific whisker by determining which section of the brain lit up when the whisker was stimulated. After whiskers were cut, over time the corresponding neural pathways in the brain failed to light up. “When we removed the stimulus, we retarded growth. The genes that controlled growth were disrupted,” Sun says.
Disrupted neural growth could be the underlying cause of epilepsy, Sun postulates. When an area of the brain is disrupted, the site of the disruption later becomes a site for abnormal neural growth. And when abnormal neural pathways form, stimuli can cause neurons to misfire down the abnormal pathway in a chain reaction. The result can be epilepsy.
Sun says this research also has applications for head trauma patients. “Loud noises or concussive blasts can cause connections between cells to become disrupted. This can cause subtle changes in the individual that are not readily apparent when using medical diagnostic equipment.”
Sun’s research is a first step toward discovering what causes neuron changes in the brain, which can lead to disease. Knowing the cause can lead to methods of prevention. Sun says this is especially important for diseases like epilepsy, where only symptoms can be treated. There is no existing cure.
Researchers are also trying to determine what triggers the overreaction to stimuli in epilepsy. Flynn uses the analogy of a car: brakes inhibit the brain’s neural transmitters, and when they fail, it speeds out of control.
Leah Selby receives EPSCORE Summer and Fall Research Fellowship Award
Leah Selby receives the EPSCoR summer research fellowship for 2006. Leah is a pre-med undergraduate student. She participates in a medically related research project in Dr Sun’s lab. This project deals with the biological basis for the Fragile-X mental retardation syndrome (FXS), which is the leading form of inherited mental retardation with incidence of 1:2000 in males and 1:4000 in females. Taking advantage of a mouse mutation for the Fragile X Syndrome, she studies cellular problems intrinsic to brain of the Fragile X mouse. This project will help to determine a correlation between onset of microstructural changes and onset of behavior deficit. This information will also help to develop novel therapeutic approaches for curing this disease (May 20th 2006). Links to Fragile-X research foundation.
Congratulations to Leah for winning the fall EPSCoR felloship again (October 1st, 2006)!
Congratulations to Leah for being accepted by University of Washinton, School of Medicine.