columns.yaml

---
HED:
  name: HED
  display_name: HED
  description: |
    Hierarchical Event Descriptor (HED) tags.
    See the [HED Appendix](SPEC_ROOT/appendices/hed.md) for details.
  type: string
abbreviation:
  name: abbreviation
  display_name: Abbreviation
  description: |
    The unique label abbreviation
  type: string
acq_time__scans:
  name: acq_time
  display_name: Scan acquisition time
  description: |
    Acquisition time refers to when the first data point in each run was acquired.
    Furthermore, if this header is provided, the acquisition times of all files
    from the same recording MUST be identical.
    Datetime format and their deidentification are described in
    [Units](SPEC_ROOT/common-principles.md#units).
  type: string
  format: datetime
acq_time__sessions:
  name: acq_time
  display_name: Session acquisition time
  description: |
    Acquisition time refers to when the first data point of the first run was acquired.
    Datetime format and their deidentification are described in
    [Units](SPEC_ROOT/common-principles.md#units).
  type: string
  format: datetime
age:
  name: age
  display_name: Subject age
  description: |
    Numeric value in years (float or integer value).

    For privacy purposes, participant ages should be capped at 89.
    Using "89+" for ages above 88 is DEPRECATED.
  definition: {
    "LongName": "Subject age",
    "Description": "Subject age in postnatal years",
    "Format": "number",
    "Units": "year",
    "Maximum": 89,
  }
age_category:
  name: age_category
  display_name: Age category
  description: |
    A non-numeric term for a subject's life cycle stage (for instance, `adult`).
    Inspired by the
    [UBERON life cycle stage](http://purl.obolibrary.org/obo/UBERON_0000105).
  type: string
  enum:
    - $ref: objects.enums.adolescent.value
    - $ref: objects.enums.adult.value
    - $ref: objects.enums.embryo.value
    - $ref: objects.enums.infant.value
    - $ref: objects.enums.juvenile.value
    - $ref: objects.enums.late_adult.value
    - $ref: objects.enums.neonate.value
    - $ref: objects.enums.perinate.value
    - $ref: objects.enums.prime_adult.value
    - $ref: objects.enums.young_adult.value
birthdate:
  name: birthdate
  display_name: Birth date
  description: |
    Date of the start of a subject's neonate stage. Date format (YYYY-MM-DD).
    Should not be provided or anonymized for human subjects.
  type: string
  format: date
birthtime:
  name: birthtime
  display_name: Birth time
  description: |
    Time (or estimated time) of birth. Time format (hh:mm:ssZ).
    Typically, this field will be combined with birthdate.
    Should not be provided or anonymized for human subjects.
  type: string
  format: time
cardiac:
  name: cardiac
  display_name: Cardiac measurement
  description: |
    continuous pulse measurement
  definition: {
    "Description": "continuous pulse measurement",
    "Format": "number",
    "Units": "mV"
  }
channel:
  name: channel
  display_name: Channel
  description: |
    Channel(s) associated with an event.
    If multiple channels are specified, they MUST be separated by a delimiter
    specified in the `"Delimiter"` field describing the `channel` column.
    For example, channels separated with a comma (`,`) require the `events.json`
    file to contain `"channel": {"Delimiter": ","}`.
    In the absence of a delimiter, tools MUST interpret any character as being part
    of a channel name.
  type: string
color:
  name: color
  display_name: Color label
  description: |
    Hexadecimal. Label color for visualization.
  type: string
  unit: hexadecimal
component:
  name: component
  display_name: Component
  description: |
    Description of the spatial axis or label of quaternion component associated with the channel.
    For example, `x`,`y`,`z` for position channels,
    or `quat_x`, `quat_y`, `quat_z`, `quat_w` for quaternion orientation channels.
  type: string
  enum:
    - $ref: objects.enums.x.value
    - $ref: objects.enums.y.value
    - $ref: objects.enums.z.value
    - $ref: objects.enums.quat_x.value
    - $ref: objects.enums.quat_y.value
    - $ref: objects.enums.quat_z.value
    - $ref: objects.enums.quat_w.value
coordinate_system:
  name: coordinate_system
  display_name: Coordinate System
  description: |
    Name of the coordinate system defined in `coordsystem.json` in which the electrode's
    `x`, `y`, and (optionally) `z` coordinates are given.
  type: string
deathdate:
  name: deathdate
  display_name: Death date
  description: |
    Date of the end of a subject's life cycle. Date format (YYYY-MM-DD).
    Should not be provided or anonymized for human subjects.
  type: string
  format: date
deathtime:
  name: deathtime
  display_name: Death time
  description: |
    Time (or estimated time) of death. Time format (hh:mm:ssZ).
    Typically, this field will be combined with deathdate.
    Should not be provided or anonymized for human subjects.
  type: string
  format: time
detector__channels:
  name: detector
  display_name: Detector Name
  description: |
    Name of the detector as specified in the `*_optodes.tsv` file.
    `n/a` for channels that do not contain NIRS signals (for example, acceleration).
  type: string
detector_type:
  name: detector_type
  display_name: Detector Type
  description: |
    The type of detector. Only to be used if the field `DetectorType` in `*_nirs.json` is set to `mixed`.
  type: string
derived_from:
  name: derived_from
  display_name: Derived from
  description: |
    `sample-<label>` entity from which a sample is derived,
    for example a slice of tissue (`sample-02`) derived from a block of tissue (`sample-01`).
  type: string
  pattern: ^sample-[0-9a-zA-Z+]+$
desc_id:
  name: desc_id
  display_name: Description Label
  description: |
    A `desc-<label>` entity present in the derivatives dataset.

    The `desc_id` column contains the labels used with the
    [`desc` entity](SPEC_ROOT/appendices/entities.md#desc),
    within the particular nesting that the `descriptions.tsv` file is placed.

    For example, if the `descriptions.tsv` file is placed at the root of the derivative dataset,
    its `desc_id` column SHOULD contain all labels of the `desc` entity)
    used across the entire derivative dataset.
  type: string
  pattern: ^desc-[0-9a-zA-Z+]+$
description:
  name: description
  display_name: Description
  description: |
    Brief free-text description of the channel, or other information of interest.
  type: string
description__optode:
  name: description
  display_name: Description
  description: |
    Free-form text description of the optode, or other information of interest.
  type: string
description__entities:
  name: description
  display_name: Description
  description: |
    Free-form text description of the entity's label (defined in `<entity>_id` column).
  type: string
dimension:
  name: dimension
  display_name: Dimension
  description: |
    Size of the group (grid/strip/probe) that this electrode belongs to.
    Must be of form `[AxB]` with the smallest dimension first (for example, `[1x8]`).
  type: string
duration:
  name: duration
  display_name: Event duration
  description: |
    Duration of the event (measured from onset) in seconds.
    Must always be either zero or positive (or `n/a` if unavailable).
    A "duration" value of zero implies that the delta function or event is so
    short as to be effectively modeled as an impulse.
  type: number
  unit: s
  minimum: 0
x_coordinate:
  name: x_coordinate
  display_name: Gaze x-coordinate
  description: |
    Gaze position x-coordinate of the recorded eye, in the coordinate
    units specified in the corresponding metadata sidecar.
  type: number
y_coordinate:
  name: y_coordinate
  display_name: Gaze y-coordinate
  description: |
    Gaze position y-coordinate of the recorded eye, in the coordinate
    units specified in the corresponding metadata sidecar.
  type: number
pupil_size:
  name: pupil_size
  display_name: Pupil size
  description: |
    Pupil size, as area or diameter, of the recorded eye, in the
    units specified in the corresponding metadata sidecar.
    It is RECOMMENDED to indicate the particular type of pupil size that is
    being recorded in the `Description` field of this column.
    It is RECOMMENDED to specify the `Units` field corresponding to this column.
  type: number
timestamp__eyetrack:
  name: timestamp
  display_name: Eye-tracking recording timestamp
  description: |
    Timestamp issued by the eye-tracker indexing the continuous recordings corresponding to
    the sampled eye.
  type: number
filename:
  name: filename
  display_name: Filename
  description: |
    Relative paths to files.
  type: string
  format: participant_relative
group__channel:
  name: group
  display_name: Channel group
  description: |
    Which group of channels (grid/strip/seeg/depth) this channel belongs to.
    This is relevant because one group has one cable-bundle and noise can be shared.
    This can be a name or number.
  type: string
group__emg:
  name: group
  display_name: Electrode or channel group
  description: |
    Which group the electrode or channel belongs to (typically this indicates electrodes
    or bipolar channels on the same grid, strip, or other device).
  anyOf:
    - type: string
    - type: number
handedness:
  name: handedness
  display_name: Subject handedness
  definition: {
    "LongName": "Subject handedness",
    "Description": "String value indicating one of \"left\", \"right\", or \"ambidextrous\".",
    "Format": "string",
    "Levels": {
      "left": "Left-handed",
      "l": "Left-handed",
      "L": "Left-handed",
      "LEFT": "Left-handed",
      "Left": "Left-handed",
      "right": "Right-handed",
      "r": "Right-handed",
      "R": "Right-handed",
      "RIGHT": "Right-handed",
      "Right": "Right-handed",
      "ambidextrous": "Ambidextrous",
      "a": "Ambidextrous",
      "A": "Ambidextrous",
      "AMBIDEXTROUS": "Ambidextrous",
      "Ambidextrous": "Ambidextrous",
    }
  }
  description: |
    String value indicating one of "left", "right", "ambidextrous".

    For "left", use one of these values: `left`, `l`, `L`, `LEFT`, `Left`.

    For "right", use one of these values: `right`, `r`, `R`, `RIGHT`, `Right`.

    For "ambidextrous", use one of these values: `ambidextrous`, `a`, `A`, `AMBIDEXTROUS`,
    `Ambidextrous`.
hemisphere:
  name: hemisphere
  display_name: Electrode hemisphere
  description: |
    The hemisphere in which the electrode is placed.
  type: string
  enum:
    - $ref: objects.enums.left_hemisphere.value
    - $ref: objects.enums.right_hemisphere.value
high_cutoff:
  name: high_cutoff
  display_name: High cutoff
  description: |
    Frequencies used for the low-pass filter applied to the channel in Hz.
    If no low-pass filter applied, use `n/a`.
    Note that hardware anti-aliasing in A/D conversion of all MEG/EEG/EMG electronics
    applies a low-pass filter; specify its frequency here if applicable.
  type: number
  unit: Hz
  minimum: 0
hplc_recovery_fractions:
  name: hplc_recovery_fractions
  display_name: HPLC recovery fractions
  description: |
    HPLC recovery fractions (the fraction of activity that gets loaded onto the HPLC).
  type: number
  unit: arbitrary
impedance:
  name: impedance
  display_name: Electrode impedance
  description: |
    Impedance of the electrode, units MUST be in `kOhm`.
  type: number
  unit: kOhm
index:
  name: index
  display_name: Label index
  description: |
    The label integer index.
  type: integer
interelectrode_distance:
  name: interelectrode_distance
  display_name: Interelectrode Distance
  description: |
    Distance between adjacent electrodes (in a pair or grid) that are rigidly attached to
    the same sensor device, or between the `signal_electrode` and its `reference`
    when each is independently placed.
  type: number
  unit: mm
low_cutoff:
  name: low_cutoff
  display_name: Low cutoff
  description: |
    Frequencies used for the high-pass filter applied to the channel in Hz.
    If no high-pass filter applied, use `n/a`.
  type: number
  unit: Hz
manufacturer:
  name: manufacturer
  display_name: Manufacturer
  description: |
    The manufacturer for each electrode.
    Can be used if electrodes were manufactured by more than one company.
  type: string
mapping:
  name: mapping
  display_name: Label mapping
  description: |
    Corresponding integer label in the standard BIDS label lookup.
  type: integer
message:
  name: message
  display_name: Message
  description: |
    Brief free-text description of a message (for example in a log generated
    by a device), or other information of interest.
  type: string
material:
  name: material
  display_name: Electrode material
  description: |
    Material of the electrode (for example, `Tin`, `Ag/AgCl`, `Gold`).
  type: string
metabolite_parent_fraction:
  name: metabolite_parent_fraction
  display_name: Metabolite parent fraction
  description: |
    Parent fraction of the radiotracer (0-1).
  type: number
  minimum: 0
  maximum: 1
metabolite_polar_fraction:
  name: metabolite_polar_fraction
  display_name: Metabolite polar fraction
  description: |
    Polar metabolite fraction of the radiotracer (0-1).
  type: number
  minimum: 0
  maximum: 1
# name column for channels.tsv files
name__channels:
  name: name
  display_name: Channel name
  description: |
    Label of the channel.
  type: string
# name column for electrodes.tsv files
name__electrodes:
  name: name
  display_name: Electrode name
  description: |
    Name of the electrode contact point.
  type: string
name__optodes:
  name: name
  display_name: Optode name
  description: |
    Name of the optode, must be unique.
  type: string
# name column for dseg.tsv files
name__segmentations:
  name: name
  display_name: Label name
  description: |
    The unique label name.
  type: string
notch:
  name: notch
  display_name: Notch frequencies
  description: |
    Frequencies used for the notch filter applied to the channel, in Hz.
    If notch filters are applied at multiple frequencies,
    these frequencies MAY be specified as a list,
    for example, `[60, 120, 180]`.
    If no notch filter was applied, use `n/a`.
  type: string
onset:
  name: onset
  display_name: Event onset
  description: |
    Onset (in seconds) of the event, measured from the beginning of the acquisition
    of the first data point stored in the corresponding task data file.
    Negative onsets are allowed, to account for events that occur prior to the first
    stored data point.
    For example, in case there is an in-scanner training phase that begins before
    the scanning sequence has started events from this sequence should have
    negative onset time counting down to the beginning of the acquisition of the
    first volume.

    If any data points have been discarded before forming the data file
    (for example, "dummy volumes" in BOLD fMRI),
    a time of 0 corresponds to the first stored data point and not the first
    acquired data point.

    A value of `n/a` value indicates the onset time is unknown or unavailable.
  type: number
  unit: s
pathology:
  name: pathology
  display_name: Pathology
  description: |
    String value describing the pathology of the sample or type of control.
    When different from `healthy`, pathology SHOULD be specified.
    The pathology may be specified in either `samples.tsv` or
    `sessions.tsv`, depending on whether the pathology changes over time.
  definition: {
    "Description": "Description of the pathology of the sample or type of control.",
    "Format": "string",
  }
participant_id:
  name: participant_id
  display_name: Participant ID
  description: |
    A participant identifier of the form `sub-<label>`,
    matching a participant entity found in the dataset.
  type: string
  pattern: ^sub-[0-9a-zA-Z+]+$
onset__physioevents:
  name: onset
  display_name: Onset of events in physiological recordings
  description: |
    Onset of the event relative to the timeline defined by the corresponding
    physiological recording file.

    Typically, it will correspond to a timestamp issued by the recording device.
  type: number
placement_description:
  name: placement_description
  display_name: Placement Scheme Description
  description: |
    Additional details of the approach to EMG sensor placement.
    See description of the `EMGPlacementSchemeDescription` field in `*_emg.json`.
  type: string
placement_scheme:
  name: placement_scheme
  display_name: Placement Scheme
  description: |
    A description of the electrode placement procedure used.
    See description of the `EMGPlacementScheme` field in `*_emg.json`.
  type: string
  enum:
    - measured
    - other
placement__motion:
  name: placement
  display_name: Placement
  description: |
    Placement of the tracked point on the body (for example,
    participant, avatar centroid, torso, left arm).
    It can refer to an external vocabulary for describing body parts.
  type: string
plasma_radioactivity:
  name: plasma_radioactivity
  display_name: Plasma radioactivity
  description: |
    Radioactivity in plasma, in unit of plasma radioactivity (for example, `kBq/mL`).
  type: number
# reference column for channels.tsv files for EEG data
reference__eeg:
  name: reference
  display_name: Electrode reference
  description: |
    Name of the reference electrode(s).
    This column is not needed when it is common to all channels.
    In that case the reference electrode(s) can be specified in `*_eeg.json` as `EEGReference`).
  type: string
# reference column for channels.tsv files for EMG data
reference__emg:
  name: reference
  display_name: Reference electrode
  description: |
    The reference for the given channel.
    When the reference is an electrode in `*_electrodes.tsv`, use the name of that electrode.
    For channels originating from bipolar devices, use `"bipolar"`.
    For non-EMG channels (for example, trigger channels, microphones) use `"n/a"`.
  type: string
# reference column for channels.tsv files for iEEG data
reference__ieeg:
  name: reference
  display_name: Electrode reference
  description: |
    Specification of the reference (for example, `mastoid`, `ElectrodeName01`, `intracranial`, `CAR`, `other`, `n/a`).
    If the channel is not an electrode channel (for example, a microphone channel) use `n/a`.
  type: string
reference_frame:
  name: reference_frame
  display_name: Reference frame
  description: |
    Specification of a reference frame in which the motion data are to be interpreted.
    The description of the levels in `*_channels.json` SHOULD use `RotationRule`,
    `RotationOrder`, and `SpatialAxes`, and MAY use `Description` for the specification.
  type: string
respiratory:
  name: respiratory
  display_name: Respiratory measurement
  description: |
    continuous breathing measurement
  definition: {
    "Description": "continuous measurements by respiration belt",
    "Format": "number",
    "Units": "mV"
  }
response_time:
  name: response_time
  display_name: Response time
  description: |
    Response time measured in seconds.
    A negative response time can be used to represent preemptive responses and
    `n/a` denotes a missed response.
  type: number
  unit: s
sample_id:
  name: sample_id
  display_name: Sample ID
  description: |
    A sample identifier of the form `sample-<label>`,
    matching a sample entity found in the dataset.
  type: string
  pattern: ^sample-[0-9a-zA-Z+]+$
sample_type:
  name: sample_type
  display_name: Sample type
  description: |
    Biosample type defined by
    [ENCODE Biosample Type](https://www.encodeproject.org/profiles/biosample_type).
  type: string
  enum:
    - $ref: objects.enums.cell_line.value
    - $ref: objects.enums.in_vitro_differentiated_cells.value
    - $ref: objects.enums.primary_cell.value
    - $ref: objects.enums.cell_free_sample.value
    - $ref: objects.enums.cloning_host.value
    - $ref: objects.enums.tissue.value
    - $ref: objects.enums.whole_organisms.value
    - $ref: objects.enums.organoid.value
    - $ref: objects.enums.technical_sample.value
sampling_frequency:
  name: sampling_frequency
  display_name: Channel sampling frequency
  description: |
    Sampling rate of the channel in Hz.
  type: number
  unit: Hz
session_id:
  name: session_id
  display_name: Session ID
  description: |
    A session identifier of the form `ses-<label>`,
    matching a session found in the dataset.
  type: string
  pattern: ^ses-[0-9a-zA-Z+]+$
sex:
  name: sex
  display_name: Sex
  description: |
    String value indicating phenotypical sex, one of "male", "female", "other".

    For "male", use one of these values: `male`, `m`, `M`, `MALE`, `Male`.

    For "female", use one of these values: `female`, `f`, `F`, `FEMALE`, `Female`.

    For "other", use one of these values: `other`, `o`, `O`, `OTHER`, `Other`.
  definition: {
    "LongName": "sex",
    "Description": "String value indicating phenotypical sex.",
    "Format": "string",
    "Levels": {
      "F": "Female",
      "FEMALE": "Female",
      "Female": "Female",
      "f": "Female",
      "female": "Female",
      "M": "Male",
      "MALE": "Male",
      "Male": "Male",
      "m": "Male",
      "male": "Male",
      "O": "Other",
      "OTHER": "Other",
      "Other": "Other",
      "o": "Other",
      "other": "Other",
    }
  }
short_channel:
  name: short_channel
  display_name: Short Channel
  description: |
    Is the channel designated as short.
    The total number of channels listed as short channels
    SHOULD be stored in `ShortChannelCount` in `*_nirs.json`.
  type: boolean
signal_electrode:
  name: signal_electrode
  display_name: Signal electrode
  description: |
    The name of the electrode from which the `reference`'s signal is subtracted to yield the channel's data.
    For channels originating from bipolar devices, the `signal_electrode` MAY be the same as the channel `name`.
  type: string
size:
  name: size
  display_name: Electrode size
  description: |
    Surface area of the electrode, units MUST be in `mm^2`.
  type: number
  unit: 'mm^2'
software_filters:
  name: software_filters
  display_name: Software filters
  description: |
    List of temporal and/or spatial software filters applied
    (for example, `SSS`, `SpatialCompensation`).
    Note that parameters should be defined in the general MEG sidecar .json file.
    Indicate `n/a` in the absence of software filters applied.
  type: string
source__channels:
  name: source
  display_name: Source name
  description: |
    Name of the source as specified in the `*_optodes.tsv` file.
    `n/a` for channels that do not contain fNIRS signals (for example, acceleration).
  type: string
source__optodes:
  name: source_type
  display_name: Source type
  description: |
    The type of source. Only to be used if the field `SourceType` in `*_nirs.json` is set to `mixed`.
  type: string
species:
  name: species
  display_name: Species
  description: |
    The `species` column SHOULD be a binomial species name from the
    [NCBI Taxonomy](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi)
    (for example, `homo sapiens`, `mus musculus`, `rattus norvegicus`).
    For backwards compatibility, if `species` is absent, the participant is assumed to be
    `homo sapiens`.
  definition: {
    "Description":
      "Latin binomial species name from the NCBI Taxonomy (https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi).",
    "Format": "string",
  }
status:
  name: status
  display_name: Channel status
  description: |
    Data quality observed on the channel.
    A channel is considered `bad` if its data quality is compromised by excessive noise.
    If quality is unknown, then a value of `n/a` may be used.
    Description of noise type SHOULD be provided in `[status_description]`.
  type: string
  enum:
    - $ref: objects.enums.good.value
    - $ref: objects.enums.bad.value
status_description:
  name: status_description
  display_name: Channel status description
  description: |
    Freeform text description of noise or artifact affecting data quality on the channel.
    It is meant to explain why the channel was declared bad in the `status` column.
  type: string
stim_file:
  name: stim_file
  display_name: Stimulus file
  description: |
    Represents the location of the stimulus file (such as an image, video, or
    audio file) presented at the given onset time.
    There are no restrictions on the file formats of the stimuli files,
    but they should be stored in the `/stimuli/` directory
    (under the root directory of the dataset; with optional subdirectories).
    The values under the `stim_file` column correspond to a path relative to
    `/stimuli`.
    For example `images/cat03.jpg` will be translated to `/stimuli/images/cat03.jpg`.
  type: string
  format: stimuli_relative
strain:
  name: strain
  display_name: Strain
  description: |
    For species different from `homo sapiens`, string value indicating
    the strain of the species, for example: `C57BL/6J`.
  definition: {
    "Description": "Name of the strain of the species.",
    "Format": "string",
  }
strain_rrid:
  name: strain_rrid
  display_name: Strain RRID
  description: |
    For species different from `homo sapiens`, research resource identifier
    ([RRID](https://rrid.site/data/source/nlx_154697-1/search))
    of the strain of the species, for example: `RRID:IMSR_JAX:000664`.
  type: string
  format: rrid
target_muscle:
  name: target_muscle
  display_name: Target muscle
  description: |
    Name of the muscle(s) from which the EMG signal in this channel is believed to originate.
    When exact muscle is unknown (such as when using electrode grids that cover multiple muscles),
    groups of muscles may be named instead (for example "flexors of the left forearm").
  type: string
time:
  name: time
  display_name: Time
  description: |
    Time, in seconds, relative to `TimeZero` defined by the `*_pet.json`.
    For example, 5.
  type: number
  unit: s
tracked_point__channels:
  name: tracked_point
  display_name: Tracked point channel
  description: |
    Label of the point that is being tracked, for example, label of a tracker
    or a marker (for example,`"LeftFoot"`, `"RightWrist"`).
  type: string
trial_type:
  name: trial_type
  display_name: Trial type
  description: |
    Primary categorisation of each trial to identify them as instances of the
    experimental conditions.
    For example: for a response inhibition task, it could take on values `go` and
    `no-go` to refer to response initiation and response inhibition experimental
    conditions.
  type: string
trigger:
  name: trigger
  display_name: Trigger
  description: |
    continuous measurement of the scanner trigger signal
  definition: {
    "Description": "continuous measurement of the scanner trigger signal",
    "Format": "number",
    "Units": "arbitrary"
  }
# type column in channels.tsv files
type__channels:
  name: type
  display_name: Channel type
  description: |
    Type of channel; MUST use the channel types listed below.
    Note that the type MUST be in upper-case.
  type: string
  enum:
    - $ref: objects.enums.ACCEL.value
    - $ref: objects.enums.ADC.value
    - $ref: objects.enums.ANGACCEL.value
    - $ref: objects.enums.AUDIO.value
    - $ref: objects.enums.DAC.value
    - $ref: objects.enums.DBS.value
    - $ref: objects.enums.ECG.value
    - $ref: objects.enums.ECOG.value
    - $ref: objects.enums.EEG.value
    - $ref: objects.enums.EMG.value
    - $ref: objects.enums.EOG.value
    - $ref: objects.enums.EYEGAZE.value
    - $ref: objects.enums.FITERR.value
    - $ref: objects.enums.GSR.value
    - $ref: objects.enums.GYRO.value
    - $ref: objects.enums.HEOG.value
    - $ref: objects.enums.HLU.value
    - $ref: objects.enums.JNTANG.value
    - $ref: objects.enums.LATENCY.value
    - $ref: objects.enums.MAGN.value
    - $ref: objects.enums.MEGGRADAXIAL.value
    - $ref: objects.enums.MEGGRADPLANAR.value
    - $ref: objects.enums.MEGMAG.value
    - $ref: objects.enums.MEGOTHER.value
    - $ref: objects.enums.MEGREFGRADAXIAL.value
    - $ref: objects.enums.MEGREFGRADPLANAR.value
    - $ref: objects.enums.MEGREFMAG.value
    - $ref: objects.enums.MISC.value
    - $ref: objects.enums.NIRSCWAMPLITUDE.value
    - $ref: objects.enums.NIRSCWFLUORESCENSEAMPLITUDE.value
    - $ref: objects.enums.NIRSCWHBO.value
    - $ref: objects.enums.NIRSCWHBR.value
    - $ref: objects.enums.NIRSCWMUA.value
    - $ref: objects.enums.NIRSCWOPTICALDENSITY.value
    - $ref: objects.enums.ORNT.value
    - $ref: objects.enums.OTHER.value
    - $ref: objects.enums.PD.value
    - $ref: objects.enums.POS.value
    - $ref: objects.enums.PPG.value
    - $ref: objects.enums.PUPIL.value
    - $ref: objects.enums.REF.value
    - $ref: objects.enums.RESP.value
    - $ref: objects.enums.SEEG.value
    - $ref: objects.enums.SYSCLOCK.value
    - $ref: objects.enums.TEMP.value
    - $ref: objects.enums.TRIG.value
    - $ref: objects.enums.VEL.value
    - $ref: objects.enums.VEOG.value
# type column for electrodes.tsv files
type__electrodes:
  name: type
  display_name: Electrode type
  description: |
    Type of the electrode (for example, cup, ring, clip-on, wire, needle).
  type: string
type__optodes:
  name: type
  display_name: Type
  description: |
    The type of the optode.
  type: string
  enum:
    - $ref: objects.enums.source.value
    - $ref: objects.enums.detector.value
units:
  name: units
  display_name: Units
  description: |
    Physical unit of the value represented in this channel,
    for example, `V` for Volt, or `fT/cm` for femto Tesla per centimeter
    (see [Units](SPEC_ROOT/common-principles.md#units)).
  type: string
  format: unit
units__nirs:
  name: units
  display_name: Units
  description: |
    Physical unit of the value represented in this channel,
    specified according to the SI unit symbol and possibly prefix symbol,
    or as a derived SI unit (for example, `V`, or unitless for changes in optical densities).
    For guidelines about units see the [Appendix](SPEC_ROOT/appendices/units.md)
    and [Common Principles](SPEC_ROOT/common-principles.md#units) pages.
  type: string
  format: unit
units__motion:
  name: units
  display_name: Units
  description: |
    Physical or virtual unit of the value represented in this channel,
    for example, '"rad"' or '"deg"' for angular quantities or '"m"' for position data.
    If motion data is recorded in a virtual space and deviate from standard SI units,
    the unit used MUST be specified in the sidecar `*_motion.json`
    file (for example `"vm"` for virtual meters). `"rad"` is used for Euler angles
    and `"n/a"` for quaternions.
    For guidelines about units see the [Appendix](SPEC_ROOT/appendices/units.md)
    and [Common Principles](SPEC_ROOT/common-principles.md#units) pages.
  type: string
  format: unit
volume_type:
  name: volume_type
  display_name: ASL volume type
  description: |
    The `*_aslcontext.tsv` table consists of a single column of labels identifying
    the `volume_type` of each volume in the corresponding `*_asl.nii[.gz]` file.
  type: string
  enum:
    - $ref: objects.enums.control.value
    - $ref: objects.enums.label.value
    - $ref: objects.enums.m0scan.value
    - $ref: objects.enums.deltam.value
    - $ref: objects.enums.cbf.value
    - $ref: objects.enums.noRF.value
wavelength_nominal:
  name: wavelength_nominal
  display_name: Wavelength nominal
  description: |
    Specified wavelength of light in nm.
    `n/a` for channels that do not contain raw NIRS signals (for example, acceleration).
    This field is equivalent to `/nirs(i)/probe/wavelengths` in the SNIRF specification.
  type: number
wavelength_actual:
  name: wavelength_actual
  display_name: Wavelength actual
  description: |
    Measured wavelength of light in nm.
    `n/a` for channels that do not contain raw NIRS signals (acceleration).
    This field is equivalent to `measurementList.wavelengthActual` in the SNIRF specification.
  type: number
wavelength_emission_actual:
  name: wavelength_emission_actual
  display_name: Wavelength emission actual
  description: |
    Measured emission wavelength of light in nm.
    `n/a` for channels that do not contain raw NIRS signals (acceleration).
    This field is equivalent to `measurementList.wavelengthEmissionActual` in the SNIRF specification.
  type: number
whole_blood_radioactivity:
  name: whole_blood_radioactivity
  display_name: Whole blood radioactivity
  description: |
    Radioactivity in whole blood samples,
    in unit of radioactivity measurements in whole blood samples (for example, `kBq/mL`).
  type: number
x:
  name: x
  display_name: X position
  description: |
    Recorded position along the x-axis.
  type: number
y:
  name: y
  display_name: Y position
  description: |
    Recorded position along the y-axis.
  type: number
z:
  name: z
  display_name: Z position
  description: |
    Recorded position along the z-axis.
  type: number
x__optodes:
  name: x
  display_name: X position
  description: |
    Recorded position along the x-axis.
    `"n/a"` if not available.
  type: number
y__optodes:
  name: y
  display_name: Y position
  description: |
    Recorded position along the y-axis.
    `"n/a"` if not available.
  type: number
z__optodes:
  name: z
  display_name: Z position
  description: |
    Recorded position along the z-axis.
    `"n/a"` if not available.
  type: number
template_x:
  name: template_x
  display_name: X template position
  description: |
    Assumed or ideal position along the x axis.
  type: number
template_y:
  name: template_y
  display_name: Y template position
  description: |
    Assumed or ideal position along the y axis.
  type: number
template_z:
  name: template_z
  display_name: Z template position
  description: |
    Assumed or ideal position along the z axis.
  type: number