Skin Conductance (SCR)

Following the BIDS Physiological recordings specification, M-BIDS uses the following additional Calibench requirements for skin conductance data.

In addition to the BIDS _physio.tsv.gz / _physio.json pair, skin conductance data MUST use the recording label scr and should be organized as follows:

physio/
├── sub-<participant_label>_task-acquisition_recording-scr_physio.json
└── sub-<participant_label>_task-acquisition_recording-scr_physio.tsv.gz

Column names in the scr data files MUST be timestamp followed by scr for experiments involving single recordings. For simultaneous parallel SCR recordings from different locations on the body, use timestamp followed by scr1, scr2, scr3, and so on.

These fields MUST be included in the JSON sidecar file: <matches>_recording-scr_physio.json

Additional Metadata Fields

Table 1: Required SCR-specific JSON fields

Key	Description	Data Type	Possible Values
SCRCouplerVoltage	Voltage of the constant voltage SCR coupler (in V).	Number	e.g., 0.5
SCRCouplerType	Type of SCR coupler.	Text	AC, DC
Placement	Position of SCR electrodes on the body.	Text	thenar/hypothenar, digits 2/3, …

Example TSV Data File

Compressed *.tsv.gz files are headerless. The columns are defined by the JSON sidecar.

0.0 3.3676146995269107
0.0004999999999881766       3.3706664573394107
0.0009999999999763531       3.3706664573394107
...

In this example, the sidecar Columns value is ["timestamp", "scr"].

Example JSON Sidecar

{
    "Columns": [
        "timestamp",
        "scr"
    ],
    "Manufacturer": "Biopac Systems",
    "ManufacturersModelName": "MP160CE",
    "DeviceSerialNumber": "1709a-0001C1F",
    "SoftwareVersion": null,
    "StartTime": 0.0,
    "PhysioType": "generic",
    "timestamp": {
        "LongName": "Time",
        "Description": "a continuously increasing identifier of the sampling time registered by the device",
        "Origin": "System startup",
        "Units": "s"
    },
    "scr": {
        "Description": "SCR Recording",
        "SCRCouplerType": "AC",
        "SCRCouplerVoltage": 0.5,
        "Placement": "right forearm",
        "Units": "uS",
        "MeasureType": "EDA-total"
    },
    "SamplingFrequency": 2000.0,
    "TrimPoints": [
        882.7075,
        1530.7065
    ],
    "Duration": 647.999
}