Action Potential Fall Time Calculator

Actual monotone falling branch90to10percent peak baseline amplitude duration, linear adjacent interpolation, no extrapolation/plateau ambiguity; not whole action potential width or assume exponentially shaped decay.

Description

A 90-to-10 percent fall time describes the descending portion of a response relative to independently established peak and baseline values.

A 90-to-10 percent fall time describes the descending portion of a response relative to independently established peak and baseline values.^[1]

This tool interpolates those crossings on a strictly falling trace without estimating whole-spike width.

When to use Action Potential Fall Time Calculator

This tool interpolates those crossings on a strictly falling trace without estimating whole-spike width.

How to use Action Potential Fall Time Calculator and how it works

Prepare descending times ms, descending voltages mv, independent peak mv, independent baseline mv, using the input definitions and matching units below.
Enter the required fields and run Action Potential Fall Time Calculator.
Read result.observedNinetyToTenFallTimeMs using the units, signs and ordering explained below.
Correct any rejected inputs and rerun; interpret the result within the stated model and its assumptions.

Input field	Meaning	Value type	Requirement
actualDescendingTimesMs	Actual Descending Times Ms. Use the units and matching context stated in the calculation below.	array of number	Required; other constraints below
actualDescendingVoltagesMv	Actual Descending Voltages Mv. Use the units and matching context stated in the calculation below.	array of number	Required; other constraints below
callerIndependentPeakMv	Caller Independent Peak Mv. Use the units and matching context stated in the calculation below.	number	Required; finite; other constraints below
callerIndependentBaselineMv	Caller Independent Baseline Mv. Use the units and matching context stated in the calculation below.	number	Required; finite; other constraints below

Require aligned time and voltage arrays with at least two points, strictly increasing finite times and strictly decreasing voltages. Require peak>baseline. Form 90% and 10% targets above baseline, require both to be bracketed, and linearly interpolate their crossing times; exact sample crossings return their timestamp. Return t10-t90 in ms, with no extrapolation, plateau handling, smoothing or whole-spike-width calculation.

target_p=baseline+p*(peak-baseline); fallTimeMs=t(target_0.1)-t(target_0.9)

Apply the input ordering, units and branch conditions stated above.

Output field	Meaning	Value type
result	Object containing the calculated or selected fields below.	object
result.observedNinetyToTenFallTimeMs	Interpolated 10% crossing time minus 90% crossing time, in ms.	number

json

{
  "input": {
    "actualDescendingTimesMs": [
      0,
      1,
      2
    ],
    "actualDescendingVoltagesMv": [
      10,
      5,
      0
    ],
    "callerIndependentPeakMv": 10,
    "callerIndependentBaselineMv": 0
  },
  "output": {
    "result": {
      "observedNinetyToTenFallTimeMs": 1.6
    }
  }
}

Limitations and assumptions

The calculation uses the supplied observations and model inputs. It does not collect measurements, select a reference population or coefficient, or establish that the model applies to the actual case. The stated branch conditions and output units remain part of the result.

All fields require explicit values. Unexpected fields, wrong types, nonfinite numbers and sparse arrays are rejected. Alignment, bounds and supported-token rules are explained above; extremely large inputs or nonfinite results can also fail. Input errors differ from successful false comparisons, unavailable-domain flags and empty match lists.

Alternative or Complementary methods

Use Synaptic Cleft Width Calculator for a complementary operation: A microscopic width measurement requires a calibration that applies to the image being measured.

Use Low Threshold Spike Amplitude Calculator for a complementary operation: A low-threshold spike amplitude requires independently identified peak and baseline values on the same voltage basis.

References

Action Potential Fall Time Calculator — tool.io

Similar or alternative tools

Synaptic Cleft Width Calculator
A microscopic width measurement requires a calibration that applies to the image being measured.
Low Threshold Spike Amplitude Calculator
A low-threshold spike amplitude requires independently identified peak and baseline values on the same voltage basis.