Naturalistic Neuroimaging Database 3T+

# NNDb-3T+: A neuroimaging database combining movie-watching, eye-tracking, sensorimotor mapping, and cognitive tasks

## Overview
The dataset is designed to support research into brain function during both naturalistic and controlled experimental conditions. Data were acquired at 3T with multiple imaging modalities, complemented by physiological and behavioral measures.
Before their visit, participants (N=40) filled out a questionnaire about demographic information, language background, musical experience, and knowledge of movies. Then the participant completed a set of cognitive tests and two scanning sessions were scheduled.
During Session 1, the participant watched the entirety of 'Back To The Future' (backtothefuture), divided into three parts. Eye-tracker calibration was performed before each part. The entire process for Session 1 took about three hours.
The participant completed several different tasks inside the scanner during Session 2: somatotopic mapping, where the participant performed movements inside the scanner; retinotopic mapping, where different checkerboard patterns were presented while the participant was instructed to fixate on the dot in the middle of the screen and respond every time the dot changed colour; tonotopic mapping, during which a sequence of beeps was played and the participant was instructed to press a button when they noticed a difference in tone. All tasks together took approximately 2.5 hours.

## Data Organization
The dataset follows the BIDS specification:
- `sub-<participant_id>` directories contain session-level raw data.
- `sourcedata/` includes raw files of eye-tracker (in asc and edf) and pulse oximetry (in tsv) data.
- `derivatives/` include preprocessing outputs.

## Contents
- **fMRI data**: Preprocessed and raw fMRI from movie-watching and mapping tasks.
- **Eye-tracking**: Calibrated gaze and pupil data synchronized with fMRI during movie-wathing and retinotopy tasks.
- **Mapping tasks**: Retinotopy, tonotopy, and somatotopy tasks.
- **Physiological recordings**: Pulse oximetry.
- **Behavioral and cognitive assessments**: Demographic and psychometric data.
- **Derivatives**: Preprocessed files including Freesurfer and AFNI outputs.

## Important Note: Movie Playback Timing
Users intending to align stimulus annotations with fMRI data should be aware of a systematic playback onset delay affecting Run 3 of the movie-watching session.

After the 8 dummy volumes are acquired and playback is triggered, there is a brief variable delay before the movie begins. Run 3 has a systematic onset delay of approximately 700ms (±80ms) across all participants, meaning the movie started ~700ms later than the annotation timestamps indicate.

Practical correction for Run 3: shift all annotation onsets by +700ms (or +18 frames at 25fps) relative to the fMRI time series. Runs 1 and 2 require no correction.

All preprocessing scripts and analysis code are available on GitHub:
[https://github.com/levchenkoegor/movieproject2](https://github.com/levchenkoegor/movieproject2)

## Access
The dataset is released under the CC-BY 4.0 License