Synaptic Charge Transfer

Integrate a baseline-corrected synaptic current by trapezoids; pA·ms yields fC. Absolute-current area is distinct from the absolute value of net charge.

Description

Synaptic charge is the integral of current after baseline subtraction.

Synaptic charge is the integral of current after baseline subtraction. Signed charge allows cancellation; absolute area accumulates both polarities.

The tool returns signedChargeFemtoCoulombs (signed charge femto coulombs); absoluteCurrentAreaFemtoCoulombs (absolute current area femto coulombs). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.

When to use Synaptic Charge Transfer

Use Synaptic Charge Transfer when you already have timesMs, currentsPa, baselinePa and want signedChargeFemtoCoulombs, absoluteCurrentAreaFemtoCoulombs. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.

How to use Synaptic Charge Transfer and understand its results

Enter timesMs, currentsPa, baselinePa 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 signedChargeFemtoCoulombs, absoluteCurrentAreaFemtoCoulombs. 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
timesMs	Times ms	list of number	Required
currentsPa	Currents pa	list of number	Required
baselinePa	Baseline pa	number	Required

Integrate piecewise-linear currents on ordered aligned times. For sign-changing intervals, split at the interpolated zero rather than trapezoidally joining absolute endpoints.

signed charge[fC] = ∫(currentPa−baselinePa)dtMs; absolute area = ∫|current−baseline|dt

The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.

json

{
  "input": {
    "timesMs": [
      0,
      1,
      2
    ],
    "currentsPa": [
      -10,
      -30,
      -10
    ],
    "baselinePa": -10
  },
  "output": {
    "signedChargeFemtoCoulombs": -20,
    "absoluteCurrentAreaFemtoCoulombs": 20
  }
}

Limitations and assumptions

Baseline is supplied. No event-window selection or recording-artifact correction occurs; pA·ms is numerically fC.

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 Current Amplitude: Measure a caller-polarity synaptic current extremum relative to a sampled baseline; inward currents preserve a negative amplitude. Synaptic Conductance: Convert a leak-subtracted voltage-clamp current trace into conductance at a fixed nonzero driving force; pA/mV yields nS.

Methodological background: Digital Library of Mathematical Functions: Quadrature.^[1]

References

Digital Library of Mathematical Functions: Quadrature — National Institute of Standards and Technology

Similar or alternative tools

Synaptic Current Amplitude
Measure a caller-polarity synaptic current extremum relative to a sampled baseline; inward currents preserve a negative amplitude.
Synaptic Conductance
Convert a leak-subtracted voltage-clamp current trace into conductance at a fixed nonzero driving force; pA/mV yields nS.