About

Scripts in this repository were constructed with the aim to facilitate analysis of Frequency Following Responses (FFR) to auditory stimulus. As of now, the script currently reads in a MATLAB data struct and assumes signal data is stored under the key 'data' of the MATLAB struct

Scripts

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Expected directory structure

project/
├── data/               # .mat EEG files (e.g. P01_MAT.mat)
├── wav/                # stimulus audio files
├── Results/            # output CSVs (auto-created by scripts)
├── fft_harmonics.py
├── resp2stim_corr.py
├── requirements.txt
└── README.md

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fft_harmonics.py

Computes FFT amplitude at specified harmonic frequencies from FFR (Frequency Following Response) EEG data exported from Letswave. For each participant file, it extracts amplitude at user-defined target frequencies and saves results to a wide-format CSV.

Input: .mat files in data/ folder, named with participant ID in format P01
Output: Results/fft_results.csv
Configure: fft_freqs, CHANNEL_NUM, BASELINE_DURATION at top of script

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resp2stim_corr.py

Computes stimulus-to-response envelope correlation between a stimulus audio file and FFR EEG responses. Returns maximum cross-correlation value and corresponding lag (ms) per participant.

Input: .wav stimulus file + .mat EEG files in data/
Output: Results/src_results.csv
Configure: audio_file path, CHANNEL_NUM, ISI, END_SAMPLE at top of script

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Setup

Windows

1. Go to python.org/downloads and download the latest installer (e.g., Python 3.x.x).
2. Run the installer. Important: Check the box that says "Add Python to PATH" before clicking Install Now.
3. Verify the installation by opening Command Prompt and running:

python --version

macOS

Python 3 can be installed via the official installer or Homebrew: Option A — Official installer: Download from python.org and run the .pkg file. Option B — Homebrew:

brew install python

Verify with

python3 --version

Installing packages required to run scripts

Go into directory of scripts, check that there's a file called requirements.txt

Run the following command in command prompt:

pip install -r requirements.txt

Run scripts

python fft_harmonics.py
python resp2stim_corr.py

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Notes

• Both scripts expect EEG data stored under the key data in the .mat file, as exported by Letswave
• Participant IDs are parsed from filenames using the pattern P followed by two digits (e.g. P01, P12)
• The Results/ directory is created automatically if it does not exist

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If you have found these scripts to be beneficial for your analysis please consider citing this repository (: