Coefficient of Variation ISI
Derive consecutive interspike intervals from ordered timestamps and calculate sample CV; differs from a generic CV of supplied measurements.
Description
Interspike intervals describe the spacing of successive spikes.
Interspike intervals describe the spacing of successive spikes. Their coefficient of variation divides sample variability by mean spacing.
The tool returns meanIsiMs (mean isi ms); sampleIsiStandardDeviationMs (sample isi standard deviation ms); isiCv (isi cv). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.
When to use Coefficient of Variation ISI
Use Coefficient of Variation ISI when you already have spikeTimesMs and want meanIsiMs, sampleIsiStandardDeviationMs, isiCv. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.
How to use Coefficient of Variation ISI and understand its results
- Enter spikeTimesMs 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 meanIsiMs, sampleIsiStandardDeviationMs, isiCv. 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 |
|---|---|---|---|
| spikeTimesMs | Spike times ms | list of number | Required |
Require at least three strictly increasing spike times, yielding at least two positive intervals. Use the N−1 denominator for interval variance.
CV = sampleSD(diff(spikeTimes))/mean(diff(spikeTimes)) The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.
{
"input": {
"spikeTimesMs": [
0,
1,
3,
6
]
},
"output": {
"meanIsiMs": 2,
"sampleIsiStandardDeviationMs": 1,
"isiCv": 0.5
}
}Limitations and assumptions
The measure pools all intervals and does not correct nonstationarity, refractory effects or missing spikes.
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
Adaptation Ratio: Compare late versus early rates derived from disjoint groups of consecutive spike intervals; ratio below one indicates slowing, not a fitted adaptation mechanism. Burst Index: Classify maximal spike runs using a supplied ISI gap and minimum burst length; report the fraction of spikes assigned to bursts, not a universal burst-index definition.
Methodological background: Measures of scale: sample variance and standard deviation.1
References
-
Measures of scale: sample variance and standard deviation — NIST/SEMATECH
Similar or alternative tools
- Adaptation Ratio
Compare late versus early rates derived from disjoint groups of consecutive spike intervals; ratio below one indicates slowing, not a fitted adaptation mechanism.
- Burst Index
Classify maximal spike runs using a supplied ISI gap and minimum burst length; report the fraction of spikes assigned to bursts, not a universal burst-index definition.