TopoToolbox: Using Sensor Topography to Calculate Psychologically Meaningful Measures from Event-Related EEG/MEG

Figure 1

Illustration of angle test and projection test with 2 sensors, although the technique is typically applied to an n-dimensional sensor space where n is the number of sensors. Each experimental condition (𝑋₁ and 𝑋₂) produces a magnitude of response for each sensor. The angle (𝜃) between these conditions is used as a measure of pattern similarity. Some other condition defines a template pattern (𝑇), and projections onto this template provide numbers for “how much” of the template each condition produced. These response magnitudes can then be compared across individuals.