specparam.utils.params.compute_knee_frequency¶
- specparam.utils.params.compute_knee_frequency(knee, exponent)[source]¶
Compute the frequency value of the knee given the aperiodic parameter values.
- Parameters:
- kneefloat
Knee parameter value.
- exponentfloat
Exponent parameter value.
- Returns:
- float
Frequency value, in Hz, of the knee occurs.
Notes
The knee frequency is an estimate of the frequency in spectrum at which the spectrum moves from the plateau region to the exponential decay.
This approach for estimating the knee frequency comes from [1] (see [2] for code).
Note that this provides an estimate of the knee frequency, but is not, in the general case, a precisely defined value. In particular, this conversion is based on the case of a Lorentzian with exponent = 2, and for other exponent values provides a non-exact approximation.
References
[1]Gao, R., van den Brink, R. L., Pfeffer, T., & Voytek, B. (2020). Neuronal timescales are functionally dynamic and shaped by cortical microarchitecture. Elife, 9, e61277. https://doi.org/10.7554/eLife.61277
