Semantic FPVS
●ValidatedPlatform: PsychoPy · French, English · · verified 1d ago
Description
Semantic Fast Periodic Visual Stimulation paradigm developed in Valentina Borghesani's lab (NoCe-Lab) at UNIGE for EEG acquisition, adapted from Joseph M. Arizpe's 2017 SSVEP code (DisplayFPVS, Harvard Medical School). Images are streamed at 6 Hz (one image every ~167 ms) in cycles of 4 standards + 1 oddball, producing an oddball rate of 1.2 Hz. The brain's response at 1.2 Hz (and harmonics, excluding multiples of 6 Hz) is an objective, implicit index of how readily the oddball category is discriminated from the standard; the 6 Hz response indexes general visual processing. Four conditions cross semantic distance (easy = high distance, hard = close distance) with stimulus integrity (original vs phase-scrambled controls). One 90-second block is run per session for a single condition selected at the startup dialog. Features preserved from the original SSVEP.py: frame-based presentation loop, optional sinusoidal opacity modulation, optional fade in/out, optional random size variation, photodiode flash at top-right on oddball onset, and parallel-port EEG triggers with condition-specific oddball codes. A web preview of this paradigm (jsPsych, 30-second blocks, no EEG hardware) is available in the catalog for demo purposes — for actual acquisition, run this PsychoPy task in the lab.
Contact & Lab
Contributors
Citation
- Arizpe, J. M. (2017). DisplayFPVS — SSVEP/FPVS stimulus presentation code. https://github.com/JosephArizpe/DisplayFPVS
- Liu-Shuang, J., Norcia, A. M., & Rossion, B. (2014). An objective index of individual face discrimination in the right occipito-temporal cortex by means of fast periodic visual stimulation. Neuropsychologia, 52, 57–72. https://doi.org/10.1016/j.neuropsychologia.2013.10.022
- Rossion, B., Torfs, K., Jacques, C., & Liu-Shuang, J. (2015). Fast periodic presentation of natural images reveals a robust face-selective electrophysiological response in the human brain. Journal of Vision, 15(1):18. https://doi.org/10.1167/15.1.18
- Lochy, A., Van Belle, G., & Rossion, B. (2015). A robust index of lexical representation in the left occipito-temporal cortex as evidenced by EEG responses to fast periodic visual stimulation. Neuropsychologia, 66, 18–31. https://doi.org/10.1016/j.neuropsychologia.2014.11.007
Credits
Adapted from DisplayFPVS by Joseph M. Arizpe (Harvard Medical School, 2017, MIT) for the NoCe-Lab Semantic FPVS EEG study at UNIGE.
Domains
Target Population
Languages
Run under
Modalities
Task Outputs
Measure implicit semantic-categorisation responses in EEG via frequency-tagged oddball detection. The 1.2 Hz EEG peak indexes the brain's automatic discrimination of the oddball category from the standard.
condition- 1.2 Hz SNR / Z-score at the oddball frequency (and harmonics, excluding 6 Hz multiples)
- 6 Hz SNR / Z-score at the base rate (general visual processing)
- Per-condition oddball-rate amplitude difference (easy vs hard) as a graded semantic-distance index
- Scrambled vs original contrast — confirms the categorisation response is form-driven
| Variable | Role | Type | Description | Unit |
|---|---|---|---|---|
image_index | metadata | number | Zero-based index of the image within the block. | - |
filename | metadata | string | Stimulus filename (relative path under the condition directory). | - |
type | independent | string | Whether the image is a standard or an oddball. Values: standard, oddball | - |
trigger_codestar | metadata | number | EEG trigger sent to the parallel port: 10 = standard, 21 / 22 / 23 / 24 = oddball in easy / hard / easy_scrambled / hard_scrambled, 100 = block start, 101 = block end. | - |
onset_time_sstar | dependent | number | Image onset time (s) from PsychoPy's clock, relative to block start. | s |
frame_number | metadata | number | Frame index at image onset (used to verify frame-locked timing on the 60 Hz display). | - |
Administration
- Duration
- ≈ 5 min
- Sessions
- 1
- Input
- keyboard
- Audio
- no audio
- Adaptivity
- fixed
- Pause / resume
- cancelNo
- Practice phase
- cancelNo
- Offline-capable
- check_circleYes
- Duration notes
- 60 s block + experimenter dialog + pre-block fixation wait. Multiple blocks (one per condition) run as separate sessions of this task.
- Hardware notes
- EEG triggers delivered via parallel port (Windows, lpt1 default 0x378). A photodiode at the top-right of the screen flashes on oddball onset for offline synchronisation. No participant response required during the stream.
- Sessions notes
- One block per condition is the standard design; run the task once per condition.
Provenance
Source: nccr-seed
Fetched: 2026-05-12
Last verified: 2026-07-16 — passed