NEURON Tutorial #13


Goals: Develop an integrated environment to test one Ih model.

Specific Aims:

Downloads:


Steps and Notes:

Let's check Sonia's Ih.

Parameters:

  • e_h = -30 mV
  • Temperature = 33 °C

Start "Main.hoc".

   

Measure membrane time constant:embrane time constant:

  • Click "Pulse (1 ms)" button.
  • Click "Initiate & Run" button.
The parameters:
gbar_h = 2.15e-5
e_pas = -70

With this set of parameters, the resting membrane potential is hyperpolarized. To have a resting potential at -65 mV, change gbar_h to 4e-5 and you will have the resting membrane potential at -65 mV. The assumption is that when Ih is blocked, the membrane potential hyperpolarizes by 5 mV.
Voltage and Current Traces (gbar_h = 2.15e-5)
Before Adjusting gbar_h
Voltage and Current Traces (gbar_h = 4e-5)
After Adjusting gbar_h
Click "Fit Decay" button. Tau = 24.3 (ms)
Tau
 

Measure Rin and Rebound Slope:

  • Click "Current Step (500 ms)" button.
  • Click "Run Step Family" button.
  • Click "Measure Rin (LR)" button.
  • Click "Measure Rebound Slope (LR)" button.
Voltage and Current Traces:
Current Step Family
Rin = 56.9 (M Ohm) (Linear Regression)
Rin by Linear Regression

Rebound Slope = -0.17 (mV/mV) (Linear Regression)
Rebound Slope

Temporal Summation:

 
  • Click "Five Alpha EPSCs (20 Hz)" button.
  • Click "Initiate & Run" button.
  • Click "Measure Temporal Summation" button.
Temporal Summation = 11.0 (%)
Temporal Summation
 

Chirp Experiment:

  • Click "Chirp" button.
  • Click "Initiate & Run" button.
  • Click "Characterize Chirp Response" button.
  • Click "Fit Impedance Amplitude" button.
  • Click "Plot Voltage Lag"
Voltage and Current Traces:
Chirp
Impedance Amplitude:
Depolarizing Resonance Frequency = 3.5 (Hz)
Hyperpolarizing Resonance Frequency = 4.5 (Hz)
Impedance Amplitude

Voltage Lag:
Voltage Lag

Voltage Clamp Experiment:

  • Click "Voltage Clamp" button.
  • Click "Run Activation Step Family" button.
  • Click "Fit GV Curve" button.
Voltage and Current Traces:
Voltage Clamp
GV Curve:
Vhalf = -81.1 (mV)
k = 7.90 (mV)
GV Curve

  • Click "Run Deactivation Step Family" button.
  • Click "Plot Tau" button.
Voltage and Current Traces:
Deactivation Step Family
Tau:
Tau