Leadfield sensitivity

hyb · December 20, 2024, 7:59am

Dear experts, I want to know how to compute the leadfield sensitivity based on the lead field matrix?

tmedani · December 20, 2024, 8:31pm

There are already options in the software that allow you to visualize the LF and qualitatively estimate the sensitivity.,
Once you have the lead field computed, you can right-click on it and then view the lead field.
This will allow you to visualize the LF either as a vector field or heatmap.

hyb · December 21, 2024, 12:52am

Oh, I know this option, I mean, how is the sensitivity estimated calculated?

tmedani · December 23, 2024, 6:04pm

The sensitivity is computed for each sensor (with ref electrode for EEG/SEEG) and for all the sources.
You can refer to this code to check how it is computed:

github.com

tmedani/brainstorm3/blob/da89cc1445bd0fadc951a5fbc57fab6fc5c67b52/toolbox/gui/view_leadfield_vectors.m#L351


      
          
          %% ===== DRAW CURRENT CHANNEL =====
              function DrawArrows()
                  % Delete previous Channels and sensors
                  delete(findobj(hAxes, '-depth', 1, 'Tag', 'lfArrows'));
                  if isprop(hAxes, 'ColorOrderIndex')
                      set(hAxes, 'ColorOrderIndex', 1);
                  else
                      set(hAxes, 'NextPlot', 'new');
                  end
                  % Draw current LF
                  for iLF = 1:length(LF_finale)
                      % EEG
                      if ismember(selectedModality, {'EEG','ECOG','SEEG'})
                          if isAvgRef
                              LeadField = LF_finale{iLF}(iChannel,:) - mean(LF_finale{iLF},1);
                              strRef = ' / Ref: Avg';
                          else
                              LeadField = LF_finale{iLF}(iChannel,:) - LF_finale{iLF}(iRef,:);
                              strRef = Channels(iRef).Name;
                          end

hyb · December 26, 2024, 12:59am

Thank you very much for your reply. Let me have a look at this code.