After reading the "Lab 8. Synaptic Connectivity" from your Crawdad CD-ROM, get started on the exercises.

Remember that if you pull on Nerve 3, you can detach it from the muscle and damage the synapses.  Also, remember that Nerve 3 innervates only the SUPERFICIAL flexor, and if you cut the superficial flexor muscle, then you will not be able to record PSPs from it.  You may instead record from the deep flexor, which is general quiescent except during escape.

Make certain that your suctrode is plugged into "Ch3" on the grey cable next to the green ground plug.  This "Ch3" is displayed in Channel 3 in the Chart Display.

Do not feel obliged to match all the PSPs to all of the spike size classes.  Perhaps concentrate on the largest and smallest units.

If you are experiencing noise in the your intracellular trace, click on that channel and the Input Amplifier and change the low-pass filter for 50 Hz or 20 Hz.  This filter will "pass" signals that are slower than 50 or 20 Hz, and filter/remove/block signals that are faster (like 60 Hz noise).  But PSPs are also about the same frequency so this may attenuate the size of your PSPs.  Always note changes in filter settings in your notebook, and also in your Chart data files.

Once you have a stable resting potential, you will probably want to increase the size of your display to see the small PSPs.
 

Questions  (answer these in your lab notebook)

Answer all questions.  Number 8 may require viewing Figure 15-5 in your textbook.

When done, clean your tools using the sonicator and the ethanol rinse.  Pat them dry with Kim-wipes and replace the covers you removed from the sharp-tipped tools.

MAKE SURE ALL OF YOUR TOOLS AND CABLES ETC. ARE IN THE CAGE.

Before leaving show your instructor that all of your data are saved in your named User folder and give the instructor your lab notebook.  Also, turn off your PowerLab and Quit all programs (to do so you need to choose File, Quit for each program [leave the Launcher and Stickies open].

Make sure your understand the lab questions.  Check with me before leaving.

Work the "Partial demyelination tutorial" simulations in the program NeuroLab of Neurons in Action.  Find this file in your Lab 1 or 2 folder on the iMacs in lab.  You can open it in Internet Explorer or in Netscape.

modified 10-5-03