cumsum_mu_synch: Determination of Motor Unit Synchronization from Cross...

In tweedell/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 based on the cumulative sum method. Peak boundaries are determined as the bins associated with 10 minimum) of the cumulative sum. The peak is considered significant if its mean bin count exceeds the sum of the mean and 1.96 * standard deviation of the baseline bins (<= -60 ms and >= 60 ms). If no significant peak is detected, a default +/- 5 ms peak is used.

Usage

cumsum_mu_synch(motor_unit_1, motor_unit_2, order = 1, binwidth =
  0.001, get_data = T, plot = F)

Arguments

motor_unit_1, 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.
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 computational histogram. Default = 0.001 or 1 ms.
get_data	T/F logical for outputting motor unit data. Default is TRUE.
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. #' 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

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)
  cumsum_mu_synch(x, y, order = 1, binwidth = 0.001, get_data = TRUE,
  plot = FALSE)

tweedell/motoRneuron documentation built on June 21, 2019, 10:43 p.m.