NEURON Tutorial #17

Goals: Create a kinetic model based on Altomare's model

Specific Aims:

• Build the Altomare's model
• Measure the following properties:
  • Membrane time constant.
  • Input resistance.
  • Rebound slope.
  • Temporal summation.
  • Impedance magnitude profile and voltage lag.
  • GV curve.
  • Tau-V curve.

Downloads:

• Alpha.hoc - For temporal summation experiment (alpha EPSCs)
• Chirp.hoc - For chirp experiment
• ExperimentControl.hoc - Experiment contols
• Fitting.hoc - Procedures for curve fitting
• GraphVI.hoc - Voltage and current graphs
• Main.hoc - Program start here
• ParameterControl.hoc - Parameter controls
• Pulse.hoc - For pulse experiment (membrane time connstant)
• RunControl.hoc - Run controls
• Step.hoc - For current step experiment (Rin, sag, rebound slope)
• VoltageClamp.hoc - Voltage clamp experiment
• h_Altomare_HCN1.mod - mod file for the kinetic scheme
• 17_Altomare_HCN1.zip - Contains all files.

Summary

Conclusion: Both models are good.

Steps and Notes:

Create "h_Altomare_2001.mod".
Create "nrnmech.dll".
Start "Main.hoc".

Membrane Time Constant:

Click "Pulse (1 ms)" button.
Click "Initiate & Run" button.
Change "gbar_h" to 1.1e-5 so the resting potential is at -65 mV.
Click "Fit Decay" button.
Tau = 24.9 (ms).

Input Resistance and Rebound Slope:

Click "Current Step (500 ms)" button.
Click "Run Step Family" button.

Click "Measure Rin (LR)" button.
Rin = 66.0 (M Ohm).

Click "Measure Rebound Slope (LR)" button.
Rebound Slope = -0.05 (mV/mV).

Temporal Summation:

Click "Five Alpha EPSCs (20 Hz)" button.
Click "Initiate & Run" button.
Click "Measure Temporal Summation" button.
Temporal Summation = 16.9 (%).

Impedance Magnitude Profile and Voltage Lag:

Click "Chirp" button.
Click "Initiate & Run" button.

Click "Characterize Chirp Response" button.
Click "Fit Impedance Amplitude" button.

Depolarizing Resonance Frequency = 2.3 (Hz)
Hyperpolarizing Resonance Frequency = 3.3 (Hz)

Click "Plot Voltage Lag" button.

G-V Curve and Tau-V Curve

Click "Voltage Clamp" button.
Click "Run Activation Step Family" button.
Click "Fit GV Curve" button.

vhalf = -69.0 (mV)
k = 9.55 (mV)

Click "Run Deactivation Step Family" button.
Click "Plot Tau" button.