Project Requirements and Status
Study overview
The objective of the tACS initiative is twofold:
- To identify a basic tACS paradigm that could be widely agreed upon in terms of theoretical efficacy; [COMPLETED]
- To conduct experiments using this paradigm across multiple research centres and investigate whether the application of tACS yields robust and replicable outcomes.
By collaborating across different sites, with complementary expertise, we aimed to increase the likelihood of obtaining conclusive findings through a multi-centre approach. In essence, our goal is to evaluate the consistency of results between centres and obtain a representative estimate of the effect size of tACS, specifically in the domain of visual perception.
Data acquisition requirements
Commitment to:
- Collect data for 20 young healthy participants (18 - 39 years old, excluding drop-outs)
- Provide a report on the stimulation and acquisition procedures following the tACS Challenge SOPs
- Share raw data and meta-files in the tACS challenge open repository
We are hoping to achieve the largest tACS study conducted to date, >30 labs, contributing data for 20 participants each = more than 600 participants!
Equipment requirements
Meet the minimum criteria in equipment settings to join the tACS challenge:
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Transcranial electric stimulator device: minimum stimulation intensity 2 mA (peak-to-peak amplitude), that can produce an alternating current at 10Hz, with 1 channel or more.
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Stimulus presentation device: a software controlled, Arduino-based visual stimulation device box that will control 5 + 1 LEDs. The custom-built Arduino set-up is currently being estimated to cost about 700-800 € per device ( devices available from here). The tACS Challenge core team has 5 devices (atm) that can be shared across labs if collaborating labs don’t want to or cannot pay for having a device made.
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Consumables and sundries: these include caps, electrodes, gel, etc.
List of equipment and consumables
| Item | Quantity | Where to find / buy1 |
|---|---|---|
| tACS device | 1 | several manufactors - see minimum specs above |
| Stimulus presentation device | 1 | available here |
| Textile Landmark Caps for tACS Cap | 1 (1 minimum, 3 suggested with different adult head sizes) | https://shop.easycap.de/ https://mes.gmbh/ |
| tACS cap electrode holders | 6 (per cap) | tACS Electrode Holders .stl files for 3D printing |
| Ten20 Gel | 3 (suggested for N=20) | several supplier options, e.g., unimed-electrodes weaverandcompany brainbox easycap |
| tACS rubber electrodes (Ø: 45 mm area: 16 cm² without hole 2 mm thick) | 3 minimum | supplier options, e.g., neurocaregroup brainbox |
| tACS rubber electrodes (Ø: 25mm area: 5cm² without hole 2 mm thick) | 5 minimum | supplier options, e.g., neurocaregroup brainbox |
| tACS electrode cables | 5 pairs minimum | supplier options, e.g., neurocaregroup brainbox |
| Current switching device2 | optional | available here |
| EMLA cream | optional |
1 Where manufacturers are listed these are just examples. We do not make specific manufacturer recommendations.
2 The current switching device allows switching between montages (i.e. different stimulation conditions). It was developed to allow for more efficient switching between the 3 montages used in the study. This is optional as the montage switching can be done manually. Details for the current switching device and associated costs can be provided upon request.
Additional data acquisition - optional
Participating labs can record EEG data as part of this study on their own initiative: Sampling rate 1000 Hz, High-pass filter: DC recording or < 0.1 Hz, Low-pass filter > 100 Hz; Channels up to 32 passive or active placed according to the 10-20 International EEG system.
Authorship
Those providing substantial contributions to the project (e.g., data collection) as co-authors, core team as corresponding authors, author list reflects degree of involvement.
Status
Completion of Registered Report Stage 1.
Tentative timeline
April 2024 - Open call for participating labs [COMPLETED]
May 2024- Registered Report Stage 1 submission [COMPLETED]
September 2024- Presentation/discussion of the approved experimental designs
November 2024- Ethics applications for participating labs
January – September 2025 - Data collection
November 2025- Data analyses completed
January 2026- Discussion of findings among participating labs
March 2026- Submission of Stage 2 Registered Report
If you have questions write us an email to tacschallenge@gmail.com