Epoch continuous EEG data

Segments continuous 2D EEG data into fixed-length epochs around events, producing a 3D array (time x channels x epochs). Optionally performs baseline correction by subtracting the mean of a pre-stimulus window.

Usage

eegEpoch(
  x,
  events,
  limits = c(-0.2, 0.8),
  baseline = c(-0.2, 0),
  assay_name = NULL,
  output_assay = "epoched"
)

Arguments

x

A PhysioExperiment object with continuous (2D) data.

events

A data.frame with an onset_sec column specifying event times in seconds, OR an integer vector of sample indices.

limits

Numeric vector of length 2 specifying the epoch window relative to each event in seconds (default: c(-0.2, 0.8)).

baseline

Numeric vector of length 2 specifying the baseline window relative to each event in seconds (default: c(-0.2, 0)). Set to NULL to skip baseline correction.

assay_name

Name of the assay to epoch. If NULL, uses defaultAssay(x).

output_assay

Name of the output assay (default: "epoched").

Value

A PhysioExperiment object with a 3D array (time x channels x epochs) in the specified output assay. Event information is stored in metadata(x)$epoch_events.

Examples

pe <- make_eeg(n_time = 10000, n_channels = 19, sr = 500)
events <- data.frame(onset_sec = c(1.0, 3.0, 5.0, 7.0))
pe_ep <- eegEpoch(pe, events, limits = c(-0.2, 0.8))
# the epoched array is stored in metadata(x)$epoched
dim(S4Vectors::metadata(pe_ep)$epoched)  # time x channels x epochs
#> [1] 501  19   4