Renaming Brain Vision Recorder EEG recordings

Renaiming Brain Vision Recorder files is a pain. Here’s a python script that makes it (more of) a breeze. The problem Brain Vision Recorder is a widely used software for EEG-recordings. Every EEG-recording is saved as three files: One .eeg file, containing all the data One .vmrk/.amrk/.bmrk file, containing markers and a reference to the .eeg file One .vhdr/.ahdr/.bhdr file, containing header information and references to the marker file and data file. This is the file that represents the recording and opened by analysis software Because of these internal references between the files, it is quite laborious (and risky) to …

Calculating d’, beta, c and Ad’ in Python and PHP

About d’ A central component of Signal Detection Theory is d’ – a measure of the ability to discriminate a signal from noise. The d’ is flanked by the parameters “beta” and c, which are measures of the criterion that the observer uses to discriminate between the two. These measures can be calculated in every experiment where there is a signal (e.g. target trials) and noise (e.g. nontarget trials), and the observer (e.g. subject) is to indicate whether the signal was present or not. d’, beta and c are statistical measures in a model where noise and noise+signal are regarded …

The case for PsychoPy

Most researchers in cognitive neuroscience have to program an experiment in a stimulus-delivery environment at some time in their career. Everyone have heard about Presentation and E-prime but much fewer have heard about PsychoPy – a free cross-platform stimulus delivery environment. Advantages over Presentation and E-Prime: Free and open source, meaning no license problems! Cross-platform. You can develop on Windows, Mac or Linux and run your experiment on Windows, Mac and Linux! Limitless functionality. Psychopy is a Python module, which means that it can be heavily extended with other Python modules for e.g. Matlab-level matrix operations (numpy), image and audio manipulations, advanced …

Computing half-area latency in matlab/EEGLAB

In EEG research the latency of a component (hidden in the ERP) is conventionally measured as the time when the ERP is most extreme. However, this method is not well warranted, as should be clear to anyone who have read Steven Lucks excellent chapters on ERP analysis in “An Introduction to the Event Related Potential Technique”. Instead he proposes a 50% area latency method: the latency is the point in time where the area under the curve is equal on both sides. It yields the same latencies as peak-measures on symmetrical ERPs and more correct latencies on non-symmetrical ERPs, where peak-measures …