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.
I am working on this project under my mentor Dr. Blackwell who is the head of the Computational and Experimental Neuroplasticity lab (CEN lab) at the Krasnow Institute. I also owe much of my interest in this subject to Dr. Blackwell and the graduate students that work under her, PhD candidates Rebekah Coleman and Sarah, both of whom have spent much of their time the past two years teaching me about various topics in Neuroscience. In the long-run I feel like I have learned so many valuable skills essential to working in any research environment, such as; applying the scientific process effectively to thoughts or research ideas, various lab skills (Histology processes, electrophysiology, neuron reconstructing using Neurolucida-7 and Bright field microscopy etc.), and critically thinking through all of the “road bumps” that naturally come with any project. In this regard I feel that my experience with CEN lab has prepared me for graduate school, whether it is applying to a Physician Assistant Master’s program or a PhD in Neuroscience.
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.