Using Brain Lab
Brain Lab allows you to carry out experiments on single brain cells. Here we will guide you through a typical brain cell study.Go to you lab by clicking on the measuring device in the Brain Lab Entrance Hall. The general procedure is to
- patch a neuron, i.e. poke a brain cell with a very fine electrode. Its tip fuses with the cell's membrane. This part is done "automatically" by Brain Lab. Check your microscope to see what this looks like.
- With the electrode we can now control the current that flows into the patched brain cell. So go back to your measuring device. You can choose one of the two on your desk. In this example we will choose the Hodgkin-Huxley device (black).
- By drawing a graph in the top orange screen, from left to right, you define the current that the electrode uses to excite the brain cell's plasma membrane.
- Now press the button above #1 or #2 on the right panel of the device to start experiment 1 or 2. The reaction of the patched neuron is calculated and plotted in the bottom orange screen. Most likely, depending on the current input you drew with your finger, you will see a number of so called action potentials the cell fired, large peaks in the plotted voltage. This is the neural code, the language in which cells communicate.
- You can now modify the x-Axis (Time) or y-Axis (current amplitude) by pressing the + or - buttons. Advanced settings can be accessed by pressing one of the edit buttons, depending on which experiment you want to modify.
- In these advanced settings you can change the reversal potentials of sodium and potassium channels and the so called leakage reversal potential (E_Na, E_K, E_L). You can also change the conductances of these three channel types (g_Na, g_K, g_L), as well as the cell's membrane capacitance c_m. Try to modify some of these parameters and compare the outcome with the original setting. You can switch back and forth between the two experiments by pressing button #1 and #2.