Spring 2013 URSP Participant: Elizabeth Benkart
My URSP project for the spring 2013 semester is looking at medium spiny neuron (MSN) dendrite morphology in the striatum of rat brains. The striatum is a very important part of the brain and is heavily involved in voluntary motor function, addiction, habit formation, and pathology in this structure leads to Parkinson’s disease. I am comparing branching patterns or the arborization of MSNs between groups of rats who have received various levels of training in a maze task with an appetitive reward. Interestingly enough there are different classes of neurons based on arborization identifiable in the striatum from birth and these classes are maintained through adulthood. Things like the MSNs spine density and branch length also change as the rat develops adult-like motor skills. However, it is unknown whether similar changes in neurons are seen in adulthood when learning a new motor task. This question is partially what sparked my interest in this project.
On a weekly basis I am normally working in CEN lab doing various histology steps in order to allow the slices of brain tissue to be cover slipped which provides longevity for reconstructing. I use Neurolucida version 7 to reconstruct neurons directly from a bright field microscope in the basement of the Krasnow Institute. After reconstructing the neuron (typically a two hour process) it can be analyzed using Neuroexplorer software where common analytical tools, such as the Scholl analysis, are used. Our analysis for this project is still under way; so far the results look promising. An interesting fact that I learned this past week in direct relation to our analysis thus far was about homeostatic plasticity; it explains that when a neuron has more synaptic input (i.e. more spines) it balances this by having a decreased intrinsic excitability and therefore does not react as strongly to stimulus; which results in a balancing act whereby the neurons overall response to a stimulus is the same. To learn more about homeostatic plasticity in the striatum please refer to the URL provided below: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0006908.
Thank You to Dr. Blackwell, Rebekah Coleman, and Sarah Hawes for their continuing support and encouragement on this project.