@@ -27,9 +27,9 @@ Each task events file REQUIRES a corresponding task data file.
2727It is also possible to have a single ` events.tsv ` file describing events
2828for all participants and runs (see
2929[ Inheritance Principle] ( ../common-principles.md#the-inheritance-principle ) ).
30- As with all other tabular data, ` events.tsv ` files MAY be accompanied by a JSON
31- file describing the columns in detail (see
32- [ Tabular Files] ( ../common-principles.md#tabular-files ) ).
30+ As with all other tabular data, ` events.tsv ` files MAY be accompanied
31+ by a JSON file describing the columns in detail
32+ (see [ Tabular Files] ( ../common-principles.md#tabular-files ) ).
3333
3434The tabular files consists of one row per event and a set of REQUIRED
3535and OPTIONAL columns:
@@ -44,26 +44,30 @@ and a guide for using macros can be found at
4444
4545The content of ` events.tsv ` files SHOULD be sorted by values in the ` onset ` column.
4646
47- Note for MRI data:
48- If any acquired scans have been discarded before forming the imaging data file,
49- ensure that an ` onset ` of 0 corresponds to the time the first image was stored.
50- For example in case there is an in scanner training phase that
51- begins before the scanning sequence has started events from this sequence should
52- have negative onset time counting down to the beginning of the acquisition of
53- the first volume.
54-
55- Note regarding the precision of numeric metadata:
56- It is RECOMMENDENDED that dataset curators specify numeric metadata like ` onset ` and
57- ` duration ` with as much decimal precision as is reasonable in the context of the experiment.
58- For example in an EEG experiment with devices operating at 1000 Hz sampling frequency,
59- dataset curators SHOULD specify ** at least** 3 figures after the decimal point.
60-
61- An arbitrary number of additional columns can be added. Those allow describing
62- other properties of events that could be later referenced in modeling and
47+ An arbitrary number of additional columns can be added.
48+ Those allow describing other properties of events that could be later referenced in modeling and
6349hypothesis extensions of BIDS.
6450Note that the ` trial_type ` and any additional columns in a TSV file
6551SHOULD be documented in an accompanying JSON sidecar file.
6652
53+ !!! note "Regarding the precision of numeric metadata"
54+
55+ For the precision of numeric metadata,
56+ it is RECOMMENDENDED that dataset curators specify numeric metadata like `onset` and
57+ `duration` with as much decimal precision as is reasonable in the context of the experiment.
58+ For example in an EEG experiment with devices operating at 1000 Hz sampling frequency,
59+ dataset curators SHOULD specify **at least** 3 figures after the decimal point.
60+
61+ !!! note "For fMRI data"
62+
63+ For fMRI data
64+ if any acquired scans have been discarded before forming the imaging data file,
65+ ensure that an `onset` of 0 corresponds to the time the first image was stored.
66+ For example in case there is an in scanner training phase that
67+ begins before the scanning sequence has started events from this sequence should
68+ have negative onset time counting down to the beginning of the acquisition of
69+ the first volume.
70+
6771Example:
6872
6973<!-- This block generates a file tree.
@@ -119,24 +123,26 @@ In the accompanying JSON sidecar, the `trial_type` column might look as follows:
119123}
120124```
121125
122- Note that in the example above:
126+ !!! note
123127
124- 1 . Only a subset of columns are described for the sake of brevity.
125- In a real dataset, all other columns SHOULD also be described.
128+ In the example above:
126129
127- 1 . The ` channel ` column contains a list of values that are separated
128- by a delimiter (` | ` ), as is declared in the ` Delimiter ` metadata
129- field of the ` events.json ` file.
130- Thus, the channels related to the event in the third row of the example
131- are called ` F,1 ` , ` F,2 ` , and ` Cz ` .
130+ 1. Only a subset of columns are described for the sake of brevity.
131+ In a real dataset, all other columns SHOULD also be described.
132132
133- 1 . The example contains a column called ` annots ` .
134- This column is not defined in BIDS, and constitutes additional, arbitrary
135- (that is, unofficial) metadata.
136- In the present case, it is used to describe artifacts in the data,
137- in reference to the ` channel ` column.
138- The ` annots ` column is making
139- use of the powerful HED system for documenting events, see below.
133+ 1. The `channel` column contains a list of values that are separated
134+ by a delimiter (`|`), as is declared in the `Delimiter` metadata field
135+ of the `events.json` file.
136+ Thus, the channels related to the event in the third row of the example
137+ are called `F,1`, `F,2`, and `Cz`.
138+
139+ 1. The example contains a column called `annots`.
140+ This column is not defined in BIDS, and constitutes additional,
141+ arbitrary (that is, unofficial) metadata.
142+ In the present case, it is used to describe artifacts in the data,
143+ in reference to the `channel` column.
144+ The `annots` column is making use of the powerful HED system
145+ for documenting events, see below.
140146
141147Events MAY also be documented in machine-actionable form
142148using HED (Hierarchical Event Descriptor) tags.
@@ -145,8 +151,8 @@ in event-related analyses.
145151See [ Hierarchical Event Descriptors] ( ../appendices/hed.md )
146152for additional information and examples.
147153
148- For multi-echo files, the ` events.tsv ` file is applicable to all echos of
149- a particular run:
154+ For multi-echo files, the ` events.tsv ` file is applicable
155+ to all echos of a particular run:
150156
151157<!-- This block generates a file tree.
152158A guide for using macros can be found at
@@ -188,8 +194,6 @@ References to existing databases can also be encoded using additional columns.
188194The following example includes references to the
189195[ Karolinska Directed Emotional Faces (KDEF) database] ( https://www.kdef.se/ ) .
190196
191- Example:
192-
193197<!-- This block generates a file tree.
194198A guide for using macros can be found at
195199 https://github.com/bids-standard/bids-specification/blob/master/macros_doc.md
@@ -235,8 +239,8 @@ in the accompanying JSON sidecar as follows:
235239}
236240```
237241
238- Note that all other columns SHOULD also be described but are omitted for the
239- sake of brevity.
242+ Note that all other columns SHOULD also be described but are omitted
243+ for the sake of brevity.
240244
241245### Stimulus presentation details
242246
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