Raw Scroller
Scroll real multichannel EEG on a 32-channel 10-20 subset, with window length, scale and montage controls and toggleable annotations.
4 claims on this page are unverified. TODO(confirm) marks a specific statement the author has not yet checked against a
primary source. Everything else on this page has been reviewed. Treat a marked claim as
provisional and go to the cited source rather than quoting the sentence.
Modes: annotated · plain · sleep — the widget below runs in annotated. Use Share state to put the exact view in the URL.
What it does
A raw-data browser for real recordings, in the browser, with no kernel. Page through 1-minute and multi-minute segments on a documented 32-channel 10-20 subset, change the window length and the µV scale, switch montage, and toggle annotations that mark blinks, saccades, muscle, alpha trains and state changes. Long segments are served as pages of at most 60 s and loaded on demand.
Controls
| Control | What it sets |
|---|---|
| Segment | Which recording to view (eyes-open / eyes-closed runs; the multi-minute transition segment; overnight segments in sleep mode) |
| Window length | Seconds per page (for example 2, 10, 30, 60) |
| Scale | µV per channel slot |
| Page | Step through the segment |
| Annotations | Show or hide labelled regions (annotated mode) |
| Montage | Referential to the recording reference, average reference, or a bipolar chain |
What to look for
annotated
- Posterior alpha appears as regular trains at O1/O2/P3/P4 when the eyes are closed and fades when they open.
- Blinks are large, rounded, frontal-polar deflections with the same polarity on both sides; saccades are steps of opposite polarity at F7 and F8.
- At 2 s per page the alpha waveform is sinusoidal; mu at C3/C4 is arch-shaped.
- Switching to a bipolar montage removes what the reference contributes to every channel.
- Annotations are algorithmic until the author reviews them; disagree with them when the trace says otherwise.
plain
- Make your own call on state and artifacts first, then compare with
annotated.
sleep
- The alpha of wakefulness disappears at sleep onset, and the trace slows and deepens as the night descends. Overnight segments from
ds-sleep-edfnow ship (ODC-By 1.0), with the recording’s own expert hypnogram and a whole-night spectrogram above the scroller. No spindles, K-complexes or slow waves are marked: the recording carries no graphoelement annotations, so the mode shows you where in the night to look and does not point at one. The shipped night is also unusual — 22.1 hours at 75 % wake, with 11 minutes of signal against a whole-night hypnogram, which is what the §4.5 size cap permits.
Used in
- L0.4 Reading raw traces (
annotated) - L7.2 Sleep EEG and staging (
sleep) - Reused as a general viewer elsewhere.
Data provenance
Segments are derivatives (cropped, resampled with an anti-alias low-pass, restricted to a documented 32-channel 10-20 subset of the source montage) of public datasets. The sidecar of each page records the source sampling rate (source_sfreq), the target rate, subject, run, start time and license; the frame shows them.
ds-eegbciR01 (eyes open, 1 min) and R02 (eyes closed, 1 min): 160 Hz kept; no hardware filters; ODC-By 1.0 (CC0 on the OpenNeuro mirror). Subject: TODO(confirm) fromdata/manifest.json.ds-dortmundeyes-closed and eyes-open 3-min blocks: resampled from 1000 Hz to 250 Hz, three 60-s pages each; CC0. Subject: TODO(confirm).ds-lemonraw, one subject, about 3 min around an eyes-open → eyes-closed block boundary: resampled from 2500 Hz to 250 Hz; CC BY 4.0 per the data descriptor, exact terms TODO(confirm) (§13 item 5). Shipped only if disk allowed; if absent, the L0.4 exercise uses its documented fallback.- Annotations carry
label_source: algorithmicuntil reviewed (§4.5).
Open the code
site/src/components/widgets/w-raw-scroller/ — Widget.svelte, index.ts, README.md. Repository link: TODO(confirm) (GitHub org/repo, §13 item 3).