1. Biol 595N: Intro to Neuroscience
Morris-Lecar Model
1/29/2004

2. Voltage Oscillations in the Barnacle Giant Muscle Fiber
Catherine Morris and Harold Lecar
Biophysical Journal 35 (1981)
1/29/2004

3. Biophysical Journal 35(1981) 193-213
1/29/2004

4. Also evidence for Ca2+ dependent K+ channels.
Experiments done in fibers excised from the depressor scutorum rostralis muscles of the Balanus nubilus.
Previous work done by many researchers had suggested this muscle is a relatively simple system that uses voltage dependent Ca2+ and K+ channels that do not inactivate under current stimulation.
Also evidence for Ca2+ dependent K+ channels.
1/29/2004

5. On the other hand, there are complicated oscillations that change dramatically with changes in the applied excitatory current.
Can the known simple channels be responsible for the complicated oscillations or is there some other, as yet undiscovered, mechanism that is contributing in an essential way?
1/29/2004

6. Ca2+ in the external solution is essential for the production of the complicated oscillations
Blocking the K+ channels also prevents the complicated oscillations from occuring.
Perfusion of the fibers by EGTA, as was done in the experiments, might cover up the slow inactivation of some Ca2+ channels
1/29/2004

7. The goal of the paper is to analyze the data collected in experiments stimulating the muscle fibers by current clamping, generating data from a mathematical model that takes into account only the K+ and Ca2+ channels, and comparing the resulting voltage responses.
1/29/2004

8. The results produced good agreement between the experiment and the model -- that is, it appears that the simple channels that have been shown to be necessary for the behavior are sufficient to explain it.
The paper further analyzed the mathematical model, as a dynamical system, to explain why the system behaves as it does.
1/29/2004