This repository contains all code to run the behavioral task used in Wittkuhn & Schuck (2020), "Dynamics of fMRI patterns reflect sub-second activation sequences and reveal replay in human visual cortex", published in Nature Communications.

Please visit our project website at https://wittkuhn.mpib.berlin/highspeed for more details about the study.

In slow trials participants have to press a button in response to upside-down visual stimuli (20% of trials) and do nothing if pictures are presented upright (80% of trials).

In sequence trials participants have to detect the serial position of a target image in a sequence of five images presented at varying speeds (32, 64, 128, 512, and 2048 ms inter-stimulus intervals) and indicate their response after a delay of 16 s after the onset of the object sequence.

In repetition trials, participants have to perform the same detection task as in sequence task, except that two out of five visual stimuli are repeated a varying number of times and participant are instructed to indicate the serial position of the first occurrence of the second (target) stimulus

• MATLAB version R2012b or higher (Natick, Massachusetts, USA; The MathWorks Inc.; see here for details)
• Psychophysics Toolbox extensions; version 3.0.11 (see here for details)

Psychtoolbox is included in this repo as a submodule and the relevant paths are accessed by the task code.

Data reported in Wittkuhn & Schuck (2020), Nature Communications were acquired using MATLAB version R2012b (Natick, Massachusetts, USA; The MathWorks Inc.) and the task was run on a Windows XP computer.

The code was successfully tested using MATLAB version R2012b and R2017a.

1. In the command line (terminal) clone this repo (if you use SSH: git clone [email protected]:lnnrtwttkhn/highspeed-task.git or if you use HTPPS: git clone https://github.com/lnnrtwttkhn/highspeed-task) which creates a folder highspeed-task in your current working directory (type pwd to find out the current working directory) that contains the files of this repo
2. Go into the highspeed-task folder using cd highspeed-task
3. Activate the Psychtoolbox-3 submodule with git submodule update --init --recursive (this clones the contents of the Psychtoolbox repo into the Psychtoolbox-3 folder)
4. Open /scripts/highspeed_run.m in MATLAB
5. Click Run in the MATLAB GUI
6. MATLAB might tell you that "to run this file, you must change the MATLAB current folder". Select the default option to Change Folder.
7. In the first dialogue box Study mode choose the study mode (e.g., instructions_condition_1 for slow trials, instructions_condition_2 for sequence and repetition trials, practice, behavioral, mri)
8. In the second dialogue box, set id, age, gender (must be either m, f, or o), session (must be either 1 or 2), run (1 to 4)
9. In the third dialogue box, confirm your settings, otherwise Cancel and go back
10. Enter the cbal counterbalancing factor (1 to 8) that determines the sequences used in sequence trials (see Methods section in the paper for details)

Task instructions for participants (in German) as used in Wittkuhn & Schuck (2020), Nature Communications can be found in highspeed_instructions.pdf.

• Lennart Wittkuhn, Max Planck Institute for Human Development, Berlin, Germany
• Nicolas W. Schuck, Max Planck Institute for Human Development, Berlin, Germany

If you use this task in your work, please use the Zenodo DOI linked above and cite the paper:

Wittkuhn, L. and Schuck, N. W. (2020). Dynamics of fMRI patterns reflect sub-second activation sequences and reveal replay in human visual cortex. Nature Communications

A preprint of the paper (old version) is available at:

Wittkuhn, L. and Schuck, N. W. (2020). Faster than thought: Detecting sub-second activation sequences with sequential fMRI pattern analysis. bioRxiv, doi: 10.1101/2020.02.15.950667.

Please see the license information below for details.

All code inside the /scripts folder was written by Lennart Wittkuhn at the Max Planck Institute for Human Development, Berlin, Germany and is licensed under the Creative Commons Attribution-ShareAlike 4.0 International Public License. Please see https://creativecommons.org/licenses/by-sa/4.0/ for details.

The visual stimuli inside the /stimuli folder are taken from Haxby et al. (2001), Science and are freely available from http:https://data.pymvpa.org/datasets/haxby2001/. The original authors of Haxby et al. (2001), Science hold the copyright of this dataset and made it available under the terms of the Creative Commons Attribution-Share Alike 3.0 license. The original images were not transformed or modified for the purpose of the current study. If you reuse the visual stimuli inside the /stimuli folder, please make sure to cite the original authors:

Haxby, J. V., Gobbini, M. I., Furey, M. L., Ishai, A., Schouten, J. L., and Pietrini, P. (2001). Distributed and overlapping representations of faces and objects in ventral temporal cortex. Science, 293(5539):2425–2430. doi: 10.1126/science.1063736

There are three different sounds used in this task, placed in the /sounds folder.

The coin sound signals correct responses. The original sound is the "Coin" sound from the Nintendo Entertainment System (NES) game "Super Mario World" and can be downloaded for free from https://themushroomkingdom.net/media/smw/wav.

The error sound signals incorrect and missed responses. The original sound is the "Yoshi spitting" sound from the Nintendo Entertainment System (NES) game "Super Mario World" and can be downloaded for free from https://themushroomkingdom.net/media/smw/wav.

In the delay period of the sequence and repetition trials (interval between the offset of the last sequence item to 16 s after sequence onset), participants listened to bird sounds to keep them moderately entertained.

The British Bird Song - Dawn Chorus were bought with a SFX (Single Use) license from evato market. Details of the SFX (Single Use) License can be found here. In short, it allows to ...

[...] use the Item to create one single End Product that incorporates the Item as well as other things, so that it is larger in scope and different in nature than the Item.

If you notice any issues or have questions of the task, please contact Lennart Wittkuhn or create an issue. Thanks!