link channels+electrodes examples

bids-standard · Mar 1, 2021 · a28c8b3 · a28c8b3
1 parent bdf03db
commit a28c8b3
Showing 1 changed file with 22 additions and 14 deletions.
diff --git a/src/04-modality-specific-files/03-electroencephalography.md b/src/04-modality-specific-files/03-electroencephalography.md
@@ -198,8 +198,10 @@ about the channels.
 Note that electrode positions SHOULD NOT be added to this file, but to [`*_electrodes.tsv`](./03-electroencephalography.md#electrodes-description-_electrodestsv).
 Furthermore, the entries in `*_electrodes.tsv` and `*_channels.tsv` do not have to match exactly,
 as for example in the case of recording a single `EOG` channel from a bipolar referencing scheme
-of two electrodes.
+of two electrodes, or a data channel originating from an auxilliary, non-electrode device.
 That is, in most cases `*_electrodes.tsv` will have more entries than `*_channels.tsv`.
+See the examples for `*_channels.tsv` below, and for `*_electrodes.tsv` in
+["Electrodes description"](./03-electroencephalography.md#electrodes-description-_electrodestsv).
 
 The columns of the Channels description table stored in `*_channels.tsv` are:
 
@@ -252,14 +254,16 @@ Example of free-form text for field `description`
 
 -   n/a, stimulus, response, skin conductance, battery status
 
-Example:
+### Example `channels.tsv`
+
+See also the corresponding [`electrodes.tsv` example](#example-electrodestsv).
 
 ```Text
-name     type   units   description                     status  status_description
-VEOG     VEOG   uV      n/a                             good    n/a
-FDI      EMG    uV      left first dorsal interosseous  good    n/a
-Cz       EEG    uV      n/a                             bad     high frequency noise
-UADC001  MISC   n/a     envelope of audio signal        good    n/a
+name     type  units  description                     reference     status  status_description
+VEOG     VEOG  uV     left eye                        VEOG-, VEOG+  good    n/a
+FDI      EMG   uV     left first dorsal interosseous  FDI-, FDI+    good    n/a
+Cz       EEG   uV     n/a                             REF           bad     high frequency noise
+UADC001  MISC  n/a    envelope of audio signal        n/a           good    n/a
 ```
 
 ## Electrodes description (`*_electrodes.tsv`)
@@ -290,15 +294,19 @@ SHOULD be present:
 | material        | RECOMMENDED           | Material of the electrode  (for example, Tin, Ag/AgCl, Gold).          |
 | impedance       | RECOMMENDED           | Impedance of the electrode, units MUST be in `kOhm`.                   |
 
-Example:
+### Example `electrodes.tsv`
+
+See also the corresponding [`electrodes.tsv` example](#example-channelstsv).
 
 ```Text
-name  x         y        z         type      material
-A1    -0.0707   0.0000   -0.0707   clip-on   Ag/AgCl
-F3    -0.0567   0.0677   0.0469    cup       Ag/AgCl
-Fz    0.0000    0.0714   0.0699    cup       Ag/AgCl
-REF   -0.0742   -0.0200  -0.0100   cup       Ag/AgCl
-GND   0.0742    -0.0200  -0.0100   cup       Ag/AgCl
+name   x        y	       z        type     material
+VEOG+  n/a      n/a      n/a      cup      Ag/AgCL
+VEOG-  n/a      n/a      n/a      cup      Ag/AgCL
+FDI+   n/a      n/a      n/a      cup      Ag/AgCL
+FDI-   n/a      n/a      n/a      cup      Ag/AgCL
+GND    -0.0707  0.0000   -0.0707  clip-on  Ag/AgCl
+Cz     0.0000   0.0714   0.0699   cup      Ag/AgCl
+REF    -0.0742  -0.0200  -0.0100  cup      Ag/AgCl
 ```
 
 The [`acq-<label>`](../99-appendices/09-entities.md#acq) key/value pair can be used to indicate acquisition of the same data. For