Reversal Potential
Estimate synaptic reversal potential from a linear leak-subtracted I–V regression, rather than an ion-concentration Nernst calculation.
Description
A linear current-voltage relation estimates conductance from slope and reversal potential where predicted current is zero.
A linear current-voltage relation estimates conductance from slope and reversal potential where predicted current is zero. pA divided by mV gives nS.
The tool returns slopeConductanceNs (slope conductance ns); reversalPotentialMv (reversal potential mv); ivRSquared (iv r squared). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.
When to use Reversal Potential
Use Reversal Potential when you already have holdingPotentialsMv, synapticCurrentsPa and want slopeConductanceNs, reversalPotentialMv, ivRSquared. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.
How to use Reversal Potential and understand its results
- Enter holdingPotentialsMv, synapticCurrentsPa using the field table below. Match the units, ordering and data boundaries described in the calculation.
- Run the tool after checking the stated bounds and matching paired observations or categories. A malformed request gives a tool error rather than a usable measurement.
- Read slopeConductanceNs, reversalPotentialMv, ivRSquared. Use the calculation and interpretation below to distinguish amounts, ratios, signs and decision flags where applicable.
- Review the supplied parameters and assumptions before using the result in a report or comparing it with another observation.
| Input field | Meaning | Value type and bounds | Requirement |
|---|---|---|---|
| holdingPotentialsMv | Holding potentials mv | list of number | Required |
| synapticCurrentsPa | Synaptic currents pa | list of number | Required |
Fit ordinary least squares with an intercept to paired holding voltages and currents. Require distinct voltages and a positive fitted conductance.
current = intercept+conductance×voltage; reversal = −intercept/conductance The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.
{
"input": {
"holdingPotentialsMv": [
-80,
-60,
-40
],
"synapticCurrentsPa": [
-40,
0,
40
]
},
"output": {
"slopeConductanceNs": 2,
"reversalPotentialMv": -60,
"ivRSquared": 1
}
}Limitations and assumptions
Rectification, multiple conductances and recording artifacts are not modelled. The zero crossing may lie outside the measured voltage range.
Numerical inputs must be finite. The tool checks its declared input shape and calculation constraints; those checks do not verify the quality, calibration or representativeness of the supplied observations.
Alternative or Complementary methods
Synaptic Conductance: Convert a leak-subtracted voltage-clamp current trace into conductance at a fixed nonzero driving force; pA/mV yields nS. Synaptic Current Amplitude: Measure a caller-polarity synaptic current extremum relative to a sampled baseline; inward currents preserve a negative amplitude.
Methodological background: Least squares estimation.1
References
-
Least squares estimation — NIST/SEMATECH
Similar or alternative tools
- Synaptic Conductance
Convert a leak-subtracted voltage-clamp current trace into conductance at a fixed nonzero driving force; pA/mV yields nS.
- Synaptic Current Amplitude
Measure a caller-polarity synaptic current extremum relative to a sampled baseline; inward currents preserve a negative amplitude.