mu_synch: Determination of Motor Unit Synchronization by Various...

In motoRneuron: Analyzing Paired Neuron Discharge Times for Time-Domain Synchronization

Description

Calculates the time-domain synchronization indices CIS, k', k'-1, S, E, SI (detailed below) between the two input motor unit discharge trains. One or more methods of peak determination can be chosen ("Visual", "Zscore", or "Cumsum"). Chosen method functions are called individually and detailed descriptions are documented in their respective help files. Motor unit characteristic data and interspike intervals are automatically output with mu_synch.

Usage

mu_synch(motor_unit_1, motor_unit_2, method = "Visual", order = 1,
  binwidth = 0.001, plot = F)

Arguments

motor_unit_1	Numeric vectors of strictly increasing numbers denoting sequential discharge times of a motor unit or neuron or any strictly increasing point process.
motor_unit_2	Numeric vectors of strictly increasing numbers denoting sequential discharge times of a motor unit or neuron or any strictly increasing point process.
method	Character vector indicating which methods of peak detection to use when quantifying synchronization. "Visual", "Zscore", and "Cumsum" are the options. Default is Visual.
order	Numeric as a positive integer for the number of forward and backward orders for calculating recurrence times. Default = 1.
binwidth	Numeric as a positive for the bin allocation size for histogram computation. Default = 0.001 or 1 ms.
plot	T/F logical for outputting the cross correlation histogram. Default is FALSE.

Value

A list of lists containing motor unit data (the names of each discharge train used, number of discharges, the interspike intervals (ISI), mean ISI, and the recurrence times associated with each order) and synchronization indices associated with chosen methods. CIS = frequency of synchronized discharges. k' = ratio of total discharges in peak to expected discharges in peak. k'-1 = ratio of synchronized discharges to expected discharges in peak. S = ratio of synchronized discharges to total number of discharges of both motor units. E = ratio of synchronized discharges to non-synchronized discharges. SI = ratio of synchronized discharges to reference motor unit discharges.

References

Keen, D.A., Chou, L., Nordstrom, M.A., Fuglevand, A.J. (2012) Short-term Synchrony in Diverse Motor Nuclei Presumed to Receive Different Extents of Direct Cortical Input. Journal of Neurophysiology 108: 3264-3275

Nordstrom, M.A., Fuglevand, A.J., Enoka, R.M. (1992) Estimating the Strength of Common Input to Human Motoneurons from the Cross-Correlogram. Journal of Physiology 453, pp. 547-574

DeFreitas, J.M., Beck, T.W., Xin, Y., Stock, M.S. (2013) Synchronization of Low- and High-Threshold Motor Units. Muscle & Nerve DOI 10.1002/mus.23978

See Also

visual_mu_synch, zscore_mu_synch, cumsum_mu_synch

Examples

  
  x <- c(0.035, 0.115, 0.183, 0.250, 0.306, 0.377, 0.455, 0.512, 0.577,
  0.656, 0.739, 0.821, 0.866, 0.950, 1.014, 1.085, 1.153, 1.213, 1.279,
  1.355, 1.431, 1.482, 1.551, 1.631, 1.692, 1.749, 1.832, 1.897, 1.964,
  2.106, 2.149, 2.229, 2.302, 2.384, 2.420, 2.505, 2.592, 2.644, 2.722,
  2.801, 2.870, 2.926, 3.011, 3.098, 2.030, 3.183, 3.252, 3.319, 3.395,
  3.469, 3.560, 3.589, 3.666, 3.744, 3.828, 3.876, 3.943, 4.020, 4.104)
  x <- sort(x)
  y <- sort(jitter(x))
  y <- round(y, digits = 3)
  mu_synch(x, y, method = c("visual", "Zscore", "Cumsum"), order = 1,
  binwidth = 0.001, plot = FALSE)

motoRneuron documentation built on May 2, 2019, 6:33 a.m.