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Plot Epochs ​

This demo demonstrates visualizing individual epoch waveforms with flexible layout options.

What is Epoch Plotting? ​

Epoch plots display individual trial timecourses, showing:

  • Single-trial waveforms: Raw epoch data (not averaged)

  • Time-locked activity: Aligned to stimulus or response events

  • Trial variability: Individual differences across repetitions

  • ERP overlay: Optional averaged waveform on top

Layout Options ​

:single (default):

  • All channels overlaid on one plot

  • Best for comparing few channels

  • Clear view of channel differences

:grid:

  • Each channel in separate subplot

  • Auto-calculated grid dimensions

  • Best for many channels

  • Synchronized axes

:topo:

  • Channels arranged by scalp position

  • Preserves spatial relationships

  • Intuitive interpretation

  • Optional scale axis

Use Cases ​

Trial-level inspection:

  • View variability across trials

  • Identify outlier epochs

  • Assess signal quality

Verify epoching:

  • Check time interval selection

  • Confirm event alignment

  • Validate baseline correction

Artifact detection:

  • Spot trial-specific artifacts

  • Find contaminated epochs

  • Guide rejection decisions

Condition comparison:

  • Overlay multiple conditions

  • Compare trial-level activity

  • Assess consistency

Customization Options ​

Channel selection:

  • Select specific channels or regions

  • Focus on electrodes of interest

Visual styling:

  • Individual trial transparency

  • Average line width

  • Color schemes

  • Axis limits

Layout parameters:

  • Grid dimensions

  • Spacing and gaps

  • Scale axis (topo layout)

Interactive Features ​

When interactive=true (default):

  • Control panel (press 'c'): Toggle conditions, adjust baseline

  • Keyboard shortcuts: Scaling, help

  • Linked axes: Synchronized zoom/pan across subplots

Workflow Summary ​

This demo shows epoch visualization workflows:

Load and Prepare Data ​

  • Read raw data

  • Apply preprocessing

  • Extract epochs

Basic Plotting ​

  • Plot single condition

  • Select specific channels

  • Compare conditions with overlay

Layout Options ​

  • Single plot: All channels together

  • Grid layout: Individual subplots

  • Topo layout: Spatial arrangement

Channel Selection ​

  • Focus on specific channels

  • Combine with different layouts

  • Maintain consistent scaling

Code Examples ​

Show Code
julia
# Demo: Epoch Plotting
# Shows epoch visualization with channel selection and overlay options.

using EegFun
# Note: EegFun.example_path() resolves bundled example data paths.
# When using your own data, simply pass the file path directly, e.g.:
# dat = EegFun.read_raw_data("/path/to/your/data.bdf")

# read raw data
dat = EegFun.read_raw_data(EegFun.example_path("data/bdf/example1.bdf"));

# read and prepare layout file
layout = EegFun.read_layout(EegFun.example_path("layouts/biosemi/biosemi72.csv"));
EegFun.polar_to_cartesian_xy!(layout)

# create EegFun data structure (EegFun.ContinuousData)
dat = EegFun.create_eegfun_data(dat, layout);

# Some minimal preprocessing (average reference and highpass filter)
EegFun.rereference!(dat, :avg)
EegFun.highpass_filter!(dat, 1)

# EPOCHS
epoch_cfg = EegFun.EpochCondition(name = "ExampleEpoch1", trigger_sequences = [[1]])
epochs = EegFun.extract_epochs(dat, epoch_cfg, (-0.5, 1.0))

# Basic plots for Epochs
EegFun.plot_epochs(epochs) # not that useful as crowded!
EegFun.plot_epochs(epochs, channel_selection = EegFun.channels([:PO7, :PO8]))

EegFun.plot_epochs(epochs, layout = :grid)
EegFun.plot_epochs(epochs, layout = :grid, channel_selection = EegFun.channels([:Fp1, :Fp2, :PO7, :PO8]))

EegFun.plot_epochs(epochs, layout = :topo)
EegFun.plot_epochs(epochs, layout = :topo, add_xy_origin = false, theme_fontsize = 10, layout_topo_show_scale = true)

EegFun.plot_epochs(epochs, channel_selection = EegFun.channels([:Fp1, :Fp2, :Cz]))
EegFun.plot_epochs(epochs, channel_selection = EegFun.channels([:Fp1, :Fp2, :Cz]); layout = :topo)

See Also ​