{"dataset":{"id":"61220","dataset_id":"on007169","name":"Multimodal Cognitive Workload n-back Task, 4 Difficulties","description":"This multimodal dataset comprises EEG, ECG, and pupillometry recordings from participants performing an n-back working memory task at four difficulty levels (1-back through 4-back). Data were collected using a combined mobile EEG+ECG system synchronized with a Pupil Labs eye tracker via Lab Streaming Layer, and converted from raw XDF recordings into BIDS format. The dataset is intended to support research on cognitive workload assessment across multiple physiological modalities.","owner_user_id":15,"status":"active","github_repo":"nemarDatasets/on007169","concept_doi":"10.82901/nemar.on007169","latest_version_doi":"10.82901/nemar.on007169.v1.0.0","created_at":"2026-06-30 02:01:33","updated_at":"2026-08-19 00:01:15","zenodo_concept_id":null,"is_sandbox":0,"visibility":"public","ezid_status":"public","enrichment_json":"{\n  \"version\": \"2.0\",\n  \"pipeline_stage\": \"validated\",\n  \"title\": \"Multimodal Cognitive Workload n-back Task, 4 Difficulties\",\n  \"description\": \"This multimodal dataset comprises EEG, ECG, and pupillometry recordings from participants performing an n-back working memory task at four difficulty levels (1-back through 4-back). Data were collected using a combined mobile EEG+ECG system synchronized with a Pupil Labs eye tracker via Lab Streaming Layer, and converted from raw XDF recordings into BIDS format. The dataset is intended to support research on cognitive workload assessment across multiple physiological modalities.\",\n  \"methods_description\": \"EEG was recorded with a 19-channel 10-20 montage using Ag/AgCl electrodes with linked-ear reference at 250 Hz, with impedance checks and Neurogel applied. ECG was recorded via a 3-lead configuration on the same mobile system. Pupillometry data were collected using a Pupil Labs Pupil Core eye tracker with infrared illuminators, relayed asynchronously via LSL. The n-back task included a tutorial phase with feedback (20 trials per level) and a main experiment (100 trials per level) without feedback, with each trial presenting a letter for 1.0 s followed by a 0.7 s blank interval.\",\n  \"license\": \"CC0\",\n  \"dataset_type\": \"raw\",\n  \"authors\": {\n    \"Matthew Barras\": {},\n    \"Liam Booth\": {}\n  },\n  \"keywords\": [\n    {\n      \"term\": \"EEG\"\n    },\n    {\n      \"term\": \"Electrocardiography\",\n      \"subject_scheme\": \"MeSH\",\n      \"value_uri\": \"http://id.nlm.nih.gov/mesh/D004562\"\n    },\n    {\n      \"term\": \"pupillometry\"\n    },\n    {\n      \"term\": \"n-back task\"\n    },\n    {\n      \"term\": \"cognitive workload\"\n    },\n    {\n      \"term\": \"working memory\"\n    },\n    {\n      \"term\": \"multimodal recording\"\n    }\n  ],\n  \"related_identifiers\": [\n    {\n      \"identifier\": \"https://github.com/nemarDatasets/on007169\",\n      \"identifier_type\": \"URL\",\n      \"relation_type\": \"IsDescribedBy\"\n    },\n    {\n      \"identifier\": \"https://nemar.org/dataset/on007169\",\n      \"identifier_type\": \"URL\",\n      \"relation_type\": \"IsDescribedBy\"\n    },\n    {\n      \"identifier\": \"10.18112/openneuro.ds007169\",\n      \"identifier_type\": \"DOI\",\n      \"relation_type\": \"IsVersionOf\"\n    },\n    {\n      \"identifier\": \"10.21105/joss.01896\",\n      \"identifier_type\": \"DOI\",\n      \"relation_type\": \"References\"\n    },\n    {\n      \"identifier\": \"10.1038/s41597-019-0104-8\",\n      \"identifier_type\": \"DOI\",\n      \"relation_type\": \"References\"\n    },\n    {\n      \"identifier\": \"10.18112/openneuro.ds007169.v1.0.5\",\n      \"identifier_type\": \"DOI\",\n      \"relation_type\": \"IsDerivedFrom\"\n    },\n    {\n      \"identifier\": \"10.1049/htl.2015.0037\",\n      \"identifier_type\": \"DOI\",\n      \"relation_type\": \"References\"\n    },\n    {\n      \"identifier\": \"10.1109/ACCESS.2021.3079992\",\n      \"identifier_type\": \"DOI\",\n      \"relation_type\": \"References\"\n    }\n  ],\n  \"resource_type_general\": \"Dataset\",\n  \"resource_type_specific\": \"EEG Dataset\",\n  \"modalities\": [\n    \"eeg\"\n  ],\n  \"sizes\": [\n    \"2.3 GB (109 files)\"\n  ],\n  \"formats\": [\n    \".eeg\",\n    \".json\",\n    \".md\",\n    \".tsv\",\n    \".vhdr\",\n    \".vmrk\",\n    \".xdf\",\n    \".yml\"\n  ],\n  \"source_hash\": \"d6f0830689da340bc25d08b89e1631ebe13630ad85f2728376833d8c5959b5f5\"\n}","last_activity_at":"2026-06-30 02:01:33","source":"openneuro","source_id":"ds007169","subject_count":18,"modalities":"eeg","age_min":18,"age_max":48,"file_size":2291328052,"total_files":228,"tasks":"nback","metadata_columns_error":null,"staleness_warn_stage":null,"staleness_admin_notified_at":null,"authors":"Matthew Barras, Liam Booth","license":"CC0","readme":"[![DOI](https://img.shields.io/badge/DOI-10.82901%2Fnemar.on007169-blue)](https://doi.org/10.82901/nemar.on007169)\n\nThis dataset was generated from LSL/XDF recordings. Converted to BIDS with instructions and code [presented here](https://github.com/LMBooth/QT-nback_study/tree/main/conversion_package)\n\n- Original recordings are stored under sourcedata/xdf/ as .xdf files (non-BIDS).\n- EEG was converted to BrainVision format (.vhdr/.eeg/.vmrk) under each sub-*/eeg/.\n- *_events.tsv was generated from marker streams and then aligned so onset is relative to the EEG start time.\n- Marker streams include task markers (n-backMarkers) and acquisition dropout annotations (UoHDataOffsetStream); events include a marker_stream column and marker definitions are in task-nback_events.json.\n- Pupil Labs gaze/pupil data was exported from the XDF pupil_capture stream into sub-*/pupil as *_task-nback_pupil.tsv + *_task-nback_eyetrack.json (PhysioType=eyetrack).\n- ECG is captured on the EEG system; the ECG channel is typed in *_channels.tsv and exported as *_recording-ecg_physio.tsv + *_recording-ecg_physio.json under sub-*/ecg.\n- Analysis note: participants excluded from the analysis remain in participants.tsv with analysis_included=false; no epoch rejection was applied to this raw dataset.\n- Participant IDs match the original XDF filenames; missing IDs correspond to excluded participants.\n\nParticipants\n- N_recorded: 20\n- N_released: 18\n- Exclusions: 2 participants excluded due to data quality failures (sub-013, sub-017).\n- Demographics in participants.tsv: age (years), sex, handedness.\n- Excluded IDs remain in participants.tsv with analysis_included=false.\n\nHardware and data collection\n- Combined EEG+ECG mobile EEG system (Bateson and Asghar, 2021; Clewett et al., 2016) and Pupil Labs Pupil Core, synchronized via Lab Streaming Layer (LSL).\n- EEG: 19-channel 10-20 montage (Fp1, Fp2, F7, F3, Fz, F4, F8, T3, C3, Cz, C4, T4, T5, P3, Pz, P4, T6, O1, O2), Ag/AgCl electrodes with linked-ear reference, 250 Hz; impedances checked and Neurgel EEG gel applied.\n- ECG: 3-lead on the same system; positive lead right shoulder/clavicle, negative lead left shoulder/clavicle, feedback lead lower left torso.\n- Pupillometry: Pupil Labs Pupil Core eye tracking with infrared illuminators; LSL relay with asynchronous sampling (timestamps per sample).\n\nProtocol summary\n- Tutorial phase with feedback: 20 trials at each level (1-back through 4-back) after a 60 s fixation.\n- Main experiment: 100 trials at each level (1-back through 4-back) with no feedback.\n- Each level begins with a 6.0 s instruction screen (\"Remember N steps back\").\n- Each trial shows a letter for 1.0 s, followed by a 0.7 s blank interval.\n- Task events encode nback_level, key_press, matched, response_accuracy, and tutorial flags in task-nback_events.json.\nTask: nback\n\nRelease notes\n- Recorded 20 participants; released 18.\n- Reason: data quality failures.\n- Participant IDs match original XDF filenames; missing IDs indicate excluded participants.\n\n\nReferences\n----------\nAppelhoff, S., Sanderson, M., Brooks, T., Vliet, M., Quentin, R., Holdgraf, C., Chaumon, M., Mikulan, E., Tavabi, K., Hochenberger, R., Welke, D., Brunner, C., Rockhill, A., Larson, E., Gramfort, A. and Jas, M. (2019). MNE-BIDS: Organizing electrophysiological data into the BIDS format and facilitating their analysis. Journal of Open Source Software 4: (1896).https://doi.org/10.21105/joss.01896\n\nPernet, C. R., Appelhoff, S., Gorgolewski, K. J., Flandin, G., Phillips, C., Delorme, A., Oostenveld, R. (2019). EEG-BIDS, an extension to the brain imaging data structure for electroencephalography. Scientific Data, 6, 103.https://doi.org/10.1038/s41597-019-0104-8\n\nClewett CJ, Langley P, Bateson AD et al (2016) Non-invasive, home-based electroencephalography hypoglycaemia warning system for personal monitoring using skin surface electrodes: a single-case feasibility study. Healthc Technol Lett 3:2-5. https://doi.org/10.1049/htl.2015.0037\n\nBateson AD, Asghar AUR (2021) Development and evaluation of a smartphone-based electroencephalography (EEG) system. IEEE Access. https://doi.org/10.1109/ACCESS.2021.3079992\n","bids_version":"1.9.0","sessions_count":null,"publish_date":null,"embedding_dirty":0,"license_tier":"public","zarr_status":"ready","zarr_converted_at":"2026-08-23 06:09:50","zarr_store_count":18,"zarr_index_etag":"1c6a88c7aa1ba38d8d54a393536a5a74","zarr_source_commit":"b0fea65f7ed3783e5a9dd3f42ac84596a5d5d436","archive_status":"ready","archive_size":1225375885,"archive_retry_count":0,"records_status":"ready","archive_skip_reason":null,"zarr_errors":0,"zarr_failure_count":0,"zarr_deterministic":0,"zarr_failed_at":null,"num_dataset_citations":0,"num_datapaper_citations":0,"n_channels":19,"electrode_system":"10-20","has_hed":0,"hed_version":null,"is_exemplar":0,"bytes_present":2289005694,"data_complete":1,"withdrawn_at":null,"withdrawn_reason":null,"archive_complete":null,"archive_absent_files":null,"archive_declared_files":null,"zarr_pool_breaks":null,"total_recording_duration":18326.352000000003,"recording_duration_min":951.312,"recording_duration_max":1160.256,"recording_count":18,"recordings_unavailable":0,"recordings_measured":18,"channel_count_min":24,"channel_count_max":24,"sampling_frequency":250,"power_line_frequency":50,"eeg_reference":"linked ears (Ag/AgCl)","placement_scheme":"based on the extended 10/20 system","sweep_stamps":"{\"enrichment_updated_at\":\"2026-08-19 00:00:53\",\"metadata_updated_at\":\"2026-08-19 00:01:12\",\"archive_checked_at\":\"2026-06-30 02:11:28\",\"zarr_checked_at\":null,\"records_checked_at\":\"2026-06-30 02:10:35\",\"citations_updated_at\":null,\"channel_montage_checked_at\":null,\"hed_checked_at\":\"2026-06-30 05:42:43\",\"data_checked_at\":\"2026-09-01 03:00:46\",\"availability_report_at\":\"2026-07-23 01:31:40\",\"recording_stats_at\":\"2026-09-02 11:33:55\",\"signal_defaults_at\":\"2026-09-02 12:52:44\"}","participants":18,"num_citations":0,"latest_version":"v1.0.0","zarr_verify_status":null,"zarr_verified_at":null,"owner_username":"nemarAdmin","owner_github":"nemarAdmin","file_size_formatted":"2.13 GB","zarr_data_failures":null,"zarr_index_url":"https://zarr.nemar.org/on007169/zarr/index.json","attestation_deposit_type":null,"attestation_key_status":null,"attestation_deidentified":null,"attestation_no_duplicate":null,"attestation_upstream_source":null,"attestation_accepted_at":null}}