The MATLAB script 'waveforms' provides tools for statistical analysis of BESA source waveforms across subjects and conditions. BESA source waveforms files (*.swf) can be loaded interactively. The contained source waveforms can be plotted. Grand average source waveforms are easily computed, and their confidence interval is calculated using the Bootstrapping BCa method. Differences between source waveforms and their confidence range can be calculated, which allows to identify latency ranges that show significant differences in the brain response in two conditions or subject groups. The 'waveforms' script also allows to determine latencies and amplitudes of individual source waveforms as well as areas under the waveforms. The obtained values can be stored in ASCII files.
The screenshot shows the analysis the activity of a frontal brain region in response to loud (100dB) auditory stimulation. The graph shows the 10 subjects' individual responses superimposed to the grand average source waveform with its 95% confidence interval.