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Phase-amplitude coupling

Source: R/coupling-pac.R
phaseAmplitudeCoupling.Rd

Quantifies how the amplitude of a fast oscillation (in amp_band) is modulated by the phase of a slow oscillation (in phase_band). The phase is taken from x and the amplitude envelope from y (or from x itself when y is NULL), each via a bandpass filter and the Hilbert transform. Supported measures are the Tort modulation index (a normalized Kullback-Leibler distance of the phase-amplitude distribution from uniform, in 0..1), the Canolty mean vector length (raw), the Ozkurt normalized mean vector length (in 0..1), and a phase-locking value.

Usage

phaseAmplitudeCoupling(
  x,
  y = NULL,
  sr = NULL,
  phase_band = c(4, 8),
  amp_band = c(30, 80),
  method = c("tort", "canolty", "ozkurt", "plv"),
  n_bins = 18L,
  order = 4L,
  modality_x = NULL,
  modality_y = NULL,
  channels_x = 1L,
  channels_y = 1L
)

Arguments

x

A numeric signal or PhysioExperiment (phase source), or a MultiPhysioExperiment.

y

A numeric signal or PhysioExperiment (amplitude source), or NULL to use x for both.

sr

Sampling rate in Hz (required for numeric input).

phase_band

Numeric length-2 phase frequency band in Hz (default: c(4, 8)).

amp_band

Numeric length-2 amplitude frequency band in Hz (default: c(30, 80)).

method

"tort", "canolty", "ozkurt", or "plv".

n_bins

Number of phase bins for the Tort modulation index (default: 18).

order

Bandpass filter order (default: 4).

modality_x, modality_y, channels_x, channels_y

Passed to the shared signal-pair extraction.

Value

A list with pac (the coupling value), method, phase_band, amp_band, and, for the Tort method, the per-bin normalized amplitude distribution and bin_centers.

References

Tort, A. B. L., et al. (2010). Measuring phase-amplitude coupling between neuronal oscillations of different frequencies. Journal of Neurophysiology, 104(2), 1195-1210.

Canolty, R. T., et al. (2006). High gamma power is phase-locked to theta oscillations in human neocortex. Science, 313(5793), 1626-1628.

See also

comodulogram(), plotComodulogram(), surrogateTest()

Examples

set.seed(1)
t <- (0:4999) / 500
ph <- 2 * pi * 6 * t
sig <- sin(ph) + (0.1 + (1 + cos(ph - pi)) / 2) * sin(2 * pi * 50 * t)
phaseAmplitudeCoupling(sig, sr = 500, phase_band = c(4, 8),
                       amp_band = c(35, 65))$pac
#> [1] 0.06449726