Tuesday, January 15, 2013

HHMI Virtual Neurophysiology Lab

Thanks to the Howard Hughes Medical Institute, it is possible to perform a neurophysiology lab online now! The specimen that was used was actually a leech. The website gave step by step instructions so even a child could perform the lab, but also gave notes and details about what exactly you were doing so it could be used at even a college level! All of the lab tools needed are included, such as: microscope, scalpel, probe, forceps, scissors, pins, dissection tray, leech tank, 20% ethanol solution to sterilize the leech, tongs, a micro manipulator, and an oscilloscope. The steps in this lab were:

  1. Anesthetize the leech in the ethanol solution.
  2. Pin the leech side up dorsal side up on the anterior and posterior suckers.
  3. Use scissors to cut the skin along the mid line on the dorsal surface. 
  4. Use the forceps to pull the skin apart.
  5. With the probe, remove the insides of the leech.
  6. Notice that there are many swellings up and down the sinus. These contain the segmental ganglia of the nervous system. To make one of them accessible, first we cut a window in the body wall underneath a ganglion, taking care not to damage the nerve cord or any attached nerves in the process.
  7.  cut a window in the body wall underneath a ganglion, taking care not to damage the nerve cord or any attached nerves in the process. 
  8. Isolate a section of the animal by making 2 parallel cuts across the animal, but sufficiently separated so that the strip you remove contains at least one ganglion. 
  9. Then, with forceps, flip the piece of skin over so that the outer skin is now face up. Pin the skin down. 
  10. Cut the sinus with an ultra fine scalpel and using fine forceps, carefully tease apart the sinus to expose the ganglion. Individual cells can now be viewed under the microscope. 
  11. In reality, you would only use the scalpel here only if you are extremely good at microdissection. It's very difficult to cut just the sinus without accidentally damaging the ganglion underneath, but hey, we are all perfect in cyber land. Normally, this is done with a pair of very fine forceps.
  12. Finally, you will have to probe and identify ganglion sensory cells. If you plan on doing this, you will need the micromanipulator, and background knowledge of electrical equipment so you can follow this procedure as professional as possible! 
     The reason I listed this is to give my blogger followers a quick lab and procedures so they dont have to go surfing on the internet to find everything I just described. The reason anybody would perform this lab would be to get a better understanding on how to measure electrical impulses and observe the structure of neurons in a model like the leech.
     My personal opinion of this virtual lab is definitely positive feedback! This lab was a great way to dissect an organism, it was really helpful for those who don't have the money for the lab equipment, or just don't have the stomach to dissect organisms. Overall, I liked everything about this lab. 
     Below is a very short video of how a neuron or nerve cell receives impulses and passes them on to other cells. It is actually pretty fascinating!

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