Adding Event Markers to Imported EEG Data - Stacked Plot

Hello!

I am currently working with Matlab to analyze EEG data from an Emotiv EPOC. I have it all imported and I have several plots made from the csv files. However, is there any way I can add (preferably manually) event markers to these plots? I have a stacked plot with all channels individually shown, a figure with all channels shown in tiled layout, and a plot with all channels shown. I've included the code below and attached the relating data files. I'm grateful for any help you can offer!

%% Importing_and_Plotting_EEG_Example
close all; clear all; clc;
% look to 300 ms for peak after stimulation
% ### EDIT: I commented out the next 4 lines so your code can be run in Answers
% % add folder with csv file to path
% addpath 'C:\Users\chris\Documents\College\Sixth Year\DAGSI\Data\EMOTIV Recordings\Event Marker Try 4'
% % change current directory to where this Matlab file is
% cd 'C:\Users\chris\Documents\College\Sixth Year\DAGSI\Data\EMOTIV Recordings'
% stops Matlab from rounding numbers
format long;

% Importing csv data
    T=readtable('Try 4.csv'); %This reads the csv data into a table named T

Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.

    timestampOrig=T.Timestamp; %this makes timestampOrig equal to the original Timestamp
    T.Timestamp=T.Timestamp-T.Timestamp(1); %This changes the official Timestamp column so it is 0 at the start of the recording 
    % Changes the sensor names from EEG_<sensor> to <sensor>
    T.Properties.VariableNames(2:end)=extractAfter(T.Properties.VariableNames(2:end),'_');
    T5=head(T, 5) %shows first 5 rows of table T

T5 = 5×15 table
         Timestamp             AF3            F7             F3             FC5            T7             P7             O1             O2             P8             T8             FC6            F4             F8             AF4    
    ___________________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    ___________

                      0    4260.384766    4267.692383    4316.025879    4305.512695           4340    4278.461426    4278.974121    4279.615234    4235.256348    4184.871582    4456.666504    4401.794922    4343.589844     4387.05127
    0.00770998001098633    4264.871582    4261.922852    4311.794922    4308.589844    4338.974121    4280.256348    4279.743652    4276.794922    4232.179688    4184.743652    4442.692383    4401.538574    4334.230957    4380.769043
     0.0155198574066162    4266.282227     4272.05127    4316.410156    4312.563965    4340.512695    4280.769043    4286.410156    4275.769043    4229.615234    4178.333496    4438.205078    4405.384766    4325.256348    4381.025879
     0.0232298374176025    4262.820313    4274.743652    4319.743652    4311.282227    4342.436035    4280.769043    4288.205078    4281.410156    4242.820313    4181.282227    4444.871582    4407.820313    4330.641113    4389.487305
     0.0310399532318115    4266.153809    4267.563965    4318.846191    4308.077148    4332.563965    4279.230957    4282.307617    4285.641113    4248.589844    4186.025879    4448.717773    4404.230957    4333.717773    4392.307617

    
%% Stacked Plot
    % Plot all electrode readings on the same plot (vs timestamp)
    fig0=figure('Name', 'EEG Signals - Stacked Plot');
    %creates a stacked plot with Timestamp as x-axis and the values of the variables in
    %columns 2:end as the y-axis
    stackedplot(T,T.Properties.VariableNames(2:end),'XVariable','Timestamp')
    grid on; xlabel('Timestamp (s)'); %turns on grid and labels the x-axis
    title('EEG Signals - Stacked Plot');
    fig0.WindowState = 'maximize'; %maximizes the figure window -> easier to see

%% Tiled Layout - Same Prominence
    fig1=figure('Name', 'EEG Signals and Peaks (Prominence=100)');
    %Sets the plots to have a tiled layout (7 rows, 2 cols) with tight
    %spacing
    hTL=tiledlayout(7,2,'TileSpacing',"tight");
    % for loop to establish the plots
    for i=2:width(T) %1 plot for each sensor
      nexttile %moves to next plot
      %finds the peaks for each sensor. The peak is currently defined as as
      %point that is at least 100 uV above the values directly to the left
      %and right of the peak value; this also plots the peaks
      findpeaks(T{:,i},T.Timestamp, 'MinPeakProminence', 100) 
      %creates ylabel as the sensor names, in bold font
      ylabel(T.Properties.VariableNames(i), 'FontWeight', 'bold')
      xticklabels('') %removes x-tick labels from the plots
      if i==14 %for the bottom left plot
          xticklabels(xticks) %x-tick labels are present
          xlabel('Timestamp (s)'); %xlabel is present
      end %ends if loop
    end %ends for loop
    xticklabels(xticks) %adds x-tick labels to bottom right graph
    grid on;
    xlabel('Timestamp (s)');
    fig1.WindowState = 'maximize';

    
%% Reg Plot - all EEG Signals and peaks on same plot
    %Plot EEG signals on same plot and find their peaks (when the peak is at
    %least 100 above the nearest values
    fig2=figure('Name', 'EEG Signals and Peaks - Same Plot');
    %sets color order to 14 different colors
    newcolors={'#0072BD', '#D95319', '#EDB120', '#7E2F8E','#77AC30','#4DBEEE', '#A2142F', '#FF0000', '#00FF00', '#0000FF', '#00FFFF', '#FF00FF', '#FFFF00', '#000000'};
    colororder(newcolors); %sets the new color order to use
    %Next 15 lines plot findpeaks for all sensors on the same plot - can
    %adjust each prominence as desired
    findpeaks(T.AF3, T.Timestamp,'MinPeakProminence',100);
    grid on; hold on; %turns on grid and plots all peaks on same plot
    findpeaks(T.F7, T.Timestamp,'MinPeakProminence',100);
    findpeaks(T.F3, T.Timestamp,'MinPeakProminence',100); 
    findpeaks(T.FC5, T.Timestamp,'MinPeakProminence',100);
    findpeaks(T.T7, T.Timestamp,'MinPeakProminence',100);
    findpeaks(T.P7, T.Timestamp,'MinPeakProminence',100);
    findpeaks(T.O1, T.Timestamp,'MinPeakProminence',100); 
    findpeaks(T.O2, T.Timestamp,'MinPeakProminence',100);
    findpeaks(T.P8, T.Timestamp,'MinPeakProminence',100);
    findpeaks(T.T8, T.Timestamp,'MinPeakProminence',100);
    findpeaks(T.FC6, T.Timestamp,'MinPeakProminence',100);
    findpeaks(T.F4, T.Timestamp,'MinPeakProminence',100);
    findpeaks(T.F8, T.Timestamp,'MinPeakProminence',100);
    findpeaks(T.AF4, T.Timestamp,'MinPeakProminence',100);
    %Creates legend for the plot
    legend({'AF3', 'AF3 Peaks', 'F7', 'F7 Peaks', 'F3', 'F3 Peaks', 'FC5', 'FC5 Peaks', 'T7', 'T7 Peaks', 'P7', 'P7 Peaks', 'O1', 'O1 Peaks', 'O2', 'O2 Peaks', 'P8', 'P8 Peaks', 'T8', 'T8 Peaks', 'FC6', 'FC6 Peaks', 'F4', 'F4 Peaks', 'F8', 'F8 Peaks', 'AF4', 'AF4 Peaks'}, 'NumColumns', 2);
    title('All Peaks on Same Graph');
    xlabel('Timestamp (s)');
    ylabel('EEG Value (uV)');
    fig2.WindowState = 'maximize';

Answer 1

[Cris LaPierre]

I guess it depends on what you want your markers to be, and how you want to select them. You can manually annotate your plot using the Figure Palette

[Christina Diersing]

I would want it to be vertical lines. If I can add an annotation, that would be great but I'd like to at least see a vertical line.

For example, I have an event marker at 3.209475 seconds, so I would like to see a vertical line (in a different color than the rest of the plot) at that point. I'd also like to be able to change the minimum peak and still have the marker, if possible.

[Cris LaPierre]

You can draw vertical lines using the xline function. I have also seen other add a stem plot to mark specific events.

[Christina Diersing]

The xline function is exactly what I'm looking for, at least for most of these. Do you know how I can use it on stacked plots? I'm trying to import the interval marker csv file, but it keeps coming up with an error stating "Error using xline (line 35). Error setting property 'Label' of class 'ConstantLine': Cell array can contain only non-empty character vectors, string vectors, or numbers."

I've inserted the relevant code below and attached the interval marker file I used.

%% Importing_and_Plotting_EEG_Example
close all; clear all; clc;
% look to 300 ms for peak after stimulation
% add folder with csv file to path
addpath 'C:\Users\chris\Documents\College\Sixth Year\DAGSI\Data\EMOTIV Recordings\Event Marker Try 4'
% change current directory to where this Matlab file is
cd 'C:\Users\chris\Documents\College\Sixth Year\DAGSI\Data\EMOTIV Recordings'
% stops Matlab from rounding numbers
format long;

% Importing csv data
    T=readtable('Try 4.csv'); %This reads the csv data into a table named T
    timestampOrig=T.Timestamp; %this makes timestampOrig equal to the original Timestamp
    T.Timestamp=T.Timestamp-T.Timestamp(1); %This changes the official Timestamp column so it is 0 at the start of the recording 
    % Changes the sensor names from EEG_<sensor> to <sensor>
    T.Properties.VariableNames(2:end)=extractAfter(T.Properties.VariableNames(2:end),'_');
    T5=head(T, 5) %shows first 5 rows of table T
        Int=readtable('Event Marker Try 4_EPOCX_126368_2021.06.04T15.42.31.04.00_intervalMarker.csv');
    EvtMar=Int.latency;
    EvtMarLab=Int.type;

%% Stacked Plot
    % Plot all electrode readings on the same plot (vs timestamp)
    fig0=figure('Name', 'EEG Signals - Stacked Plot');
    %creates a stacked plot with Timestamp as x-axis and the values of the variables in
    %columns 2:end as the y-axis
    stackedplot(T,T.Properties.VariableNames(2:end),'XVariable','Timestamp')
    xline(EvtMar, '-', {EvtMarLab})
    grid on; xlabel('Timestamp (s)'); %turns on grid and labels the x-axis
    title('EEG Signals - Stacked Plot');
    fig0.WindowState = 'maximize'; %maximizes the figure window -> easier to see

[Cris LaPierre]

I think you might find this Answers post helpful.

[Christina Diersing]

Perfect! Thank you so much for your help! I'm looking to add labels to the lines so I asked on that thread. If you can help with that or direct me to an answers post that covers that, that would be great!

For anyone who is interested, this is what it currently looks like:

%% Importing_and_Plotting_EEG_007
close all; clear all; clc;
% look to 300 ms for peak after stimulation
% stops Matlab from rounding numbers
format long;

% Importing csv data
    T=readtable('Subject 007.csv'); %This reads the csv data into a table named T
    timestampOrig=T.Timestamp; %this makes timestampOrig equal to the original Timestamp
    T.Timestamp=T.Timestamp-T.Timestamp(1); %This changes the official Timestamp column so it is 0 at the start of the recording 
    % Changes the sensor names from EEG_<sensor> to <sensor>
    T.Properties.VariableNames(2:end)=extractAfter(T.Properties.VariableNames(2:end),'_');
    %T5=head(T, 5) %shows first 5 rows of table T
    Int=readtable('Subject 007_EPOCX_140710_2021.10.20T16.08.16.04.00_intervalMarker.csv');
    EvtMar=Int.latency;
    EvtMarLab=Int.type;
    
%% Stacked Plot
    % Plot all electrode readings on the same plot (vs timestamp)
    fig0=figure('Name', 'Subject 007 EEG Signals - Stacked Plot');
    %creates a stacked plot with Timestamp as x-axis and the values of the variables in
    %columns 2:end as the y-axis
    sp=stackedplot(T,T.Properties.VariableNames(2:end),'XVariable','Timestamp')
    ax = findobj(sp.NodeChildren, 'Type','Axes');
    arrayfun(@(sp)xline(sp,EvtMar,'LineWidth',1),ax);
    grid on; xlabel('Timestamp (s)'); %turns on grid and labels the x-axis
    title('Subject 007 EEG Signals - Stacked Plot');
    fig0.WindowState = 'maximize'; %maximizes the figure window -> easier to see
%% Tiled Layout - Same Prominence
    fig1=figure('Name', 'Subject 007 EEG Signals and Peaks (Prominence=400)');
    %title('Subject 007 EEG Signals and Peaks (Prominence=400)'); %have to
    %add title manually
    fig1.WindowState = 'maximize';
    %Sets the plots to have a tiled layout (7 rows, 2 cols) with tight
    %spacing
    hTL=tiledlayout(7,2,'TileSpacing',"tight");
    % for loop to establish the plots
    for i=2:width(T) %1 plot for each sensor
      nexttile %moves to next plot
      %finds the peaks for each sensor. The peak is currently defined as as
      %point that is at least 400 uV above the values directly to the left
      %and right of the peak value; this also plots the peaks
      findpeaks(T{:,i},T.Timestamp, 'MinPeakProminence', 400) 
      xline(EvtMar, '-', {EvtMarLab})
      %xline(EvtMar, '-');
      %creates ylabel as the sensor names, in bold font
      ylabel(T.Properties.VariableNames(i), 'FontWeight', 'bold')
      xticklabels('') %removes x-tick labels from the plots
      if i==14 %for the bottom left plot
          xticklabels(xticks) %x-tick labels are present
          xlabel('Timestamp (s)'); %xlabel is present
      end %ends if loop
    end %ends for loop
    xticklabels(xticks) %adds x-tick labels to bottom right graph
    grid on;
    xlabel('Timestamp (s)');
    
    
%% Reg Plot - all EEG Signals and peaks on same plot
    %Plot EEG signals on same plot and find their peaks (when the peak is at
    %least 400 above the nearest values
    fig2=figure('Name', 'Subject 007 EEG Signals and Peaks - Same Plot Prominence: 400');
    title('Subject 007 EEG Signals and Peaks - Same Plot Prominence: 400');
    fig2.WindowState = 'maximize';
    %sets color order to 14 different colors
    newcolors={'#0072BD', '#D95319', '#EDB120', '#7E2F8E','#77AC30','#4DBEEE', '#A2142F', '#FF0000', '#9000de', '#0000FF', '#00FFFF', '#FF00FF', '#2fde00', '#8a8a8a'};
    colororder(newcolors); %sets the new color order to use
    mnpkprom=400; %min peak prominence (if you want most/all to be the same)
    %Next 15 lines plot findpeaks for all sensors on the same plot - can
    %adjust each prominence as desired
    findpeaks(T.AF3, T.Timestamp,'MinPeakProminence',mnpkprom);
    grid on; hold on; %turns on grid and plots all peaks on same plot
    findpeaks(T.F7, T.Timestamp,'MinPeakProminence',mnpkprom);
    findpeaks(T.F3, T.Timestamp,'MinPeakProminence',mnpkprom); 
    findpeaks(T.FC5, T.Timestamp,'MinPeakProminence',mnpkprom);
    findpeaks(T.T7, T.Timestamp,'MinPeakProminence',mnpkprom);
    findpeaks(T.P7, T.Timestamp,'MinPeakProminence',mnpkprom);
    findpeaks(T.O1, T.Timestamp,'MinPeakProminence',mnpkprom); 
    findpeaks(T.O2, T.Timestamp,'MinPeakProminence',mnpkprom);
    findpeaks(T.P8, T.Timestamp,'MinPeakProminence',mnpkprom);
    findpeaks(T.T8, T.Timestamp,'MinPeakProminence',mnpkprom);
    findpeaks(T.FC6, T.Timestamp,'MinPeakProminence',mnpkprom);
    findpeaks(T.F4, T.Timestamp,'MinPeakProminence',mnpkprom);
    findpeaks(T.F8, T.Timestamp,'MinPeakProminence',mnpkprom);
    findpeaks(T.AF4, T.Timestamp,'MinPeakProminence',mnpkprom);
    xline(EvtMar, '--', {'Ns','08','15','22','Ns','Ec','Mo','Ns','08','15','22','Ns','Mo','Mt','Ea','Md','Hr','Mt','Mt','Ea','Md','Hr'})
    %Creates legend for the plot
    legend({'AF3', 'AF3 Peaks', 'F7', 'F7 Peaks', 'F3', 'F3 Peaks', 'FC5', 'FC5 Peaks', 'T7', 'T7 Peaks', 'P7', 'P7 Peaks', 'O1', 'O1 Peaks', 'O2', 'O2 Peaks', 'P8', 'P8 Peaks', 'T8', 'T8 Peaks', 'FC6', 'FC6 Peaks', 'F4', 'F4 Peaks', 'F8', 'F8 Peaks', 'AF4', 'AF4 Peaks'}, 'NumColumns', 2);
    xlabel('Timestamp (s)');
    ylabel('EEG Value (uV)');

[Cris LaPierre]

You can add a label to an xline.

• xline(x,LineSpec,labels)

See on the xline documentation page

[Christina Diersing]

Thank you!

For most of my plots, I used this line of code:

    xline(EvtMar,'--',{'EO','BE','BE','BE','EC','BE','CE','CE','BE','OM','OM'}); %Vertical Lines as event markers

For the stacked plots, I used these

    sp=stackedplot(T,T.Properties.VariableNames(2:end),'XVariable','Timestamp')
    ax = findobj(sp.NodeChildren, 'Type','Axes');
    arrayfun(@(sp)xline(sp,EvtMar,'--',{'EO','BE','BE','BE','EC','BE','CE','CE','BE','OM','OM'}),ax);
    grid on; xlabel('Timestamp (s)'); %turns on grid and labels the x-axis
    title('EEG Signals - Stacked Plot');
    fig0.WindowState = 'maximize'; %maximizes the figure window -> easier to see