{"success":true,"database":"eegdash","data":{"_id":"6953f4249276ef1ee07a33ed","dataset_id":"ds005491","associated_paper_doi":null,"authors":["Haydn G. Herrema","Michael J. Kahana"],"bids_version":"1.7.0","contact_info":["Haydn Herrema"],"contributing_labs":null,"data_processed":false,"dataset_doi":"doi:10.18112/openneuro.ds005491.v1.0.0","datatypes":["ieeg"],"demographics":{"subjects_count":19,"ages":[31,36,24,27,33,40,49,28,34,28,20,36,45,26,24,44,22,21,28],"age_min":20,"age_max":49,"age_mean":31.36842105263158,"species":null,"sex_distribution":{"f":10,"m":9},"handedness_distribution":{"r":17,"l":2}},"experimental_modalities":null,"external_links":{"source_url":"https://openneuro.org/datasets/ds005491","osf_url":null,"github_url":null,"paper_url":null},"funding":["DARPA RAM: N66001-14-2-4032"],"ingestion_fingerprint":"109dc4c38bc246d7c21f1e5108a6bfb0b5279996eae538081d53770aec5c030b","license":"CC0","n_contributing_labs":null,"name":"Categorized Free Recall with Open-Loop Stimulation at Encoding","readme":"### Categorized Free Recall with Open-Loop Stimulation at Encoding\n#### Description\nThis dataset contains behavioral events and intracranial electrophysiological recordings from a categorized free recall task with open-loop stimulation at encoding.  The experiment consists of participants studying a list of words, presented visually one at a time, completing simple arithmetic problems that function as a distractor, and then freely recalling the words from the just-presented list in any order.  The data was collected at clinical sites across the country as part of a collaboration with the Computational Memory Lab at the University of Pennsylvania.\nThe word lists in this paradigm follow a specific semantic construction.  Each word comes from one of 25 semantic categories, and each list of 12 items contains 6 pairs of same-category words from 3 different categories.  This means that each list has 4 words from 3 semantic categories, and in each half of the list there will be 1 pair of words from each category.  For example, if a list contains words from categories A, B, and C, a possible list construction would be:\n**A1 - A2 - B1 - B2 - C1 - C2 - A3 - A4 - C3 - C4 - B3 - B4**\nThis study contains open-loop electrical stimulation of the brain during encoding.  There is no stimulation during the distractor or retrieval phases.  Stimulation is delivered to a single electrode at a time, with locations chosen in the hippocampus and entorhinal cortex.  Stimulation parameters are included in the behavioral events tsv files, denoting the anode/cathode labels, amplitude, pulse frequency, pulse width, and pulse count.\n20 of the 25 lists in a session are randomly assigned as stimulation lists.  On these lists, stimulation occurs on alternating two-word blocks, meaning 6 of the 12 words are presented with stimulation.  Stimulation starts 200 ms prior to the onset of the first word in the block and lasts for 4.6 seconds, ending 200-450 ms after the offset of the second word (depending on the inter-stimulus interval).  Half of the stimulation lists begin with a stimulation on pair and half begin with a stumulation off pair, but the order of these conditions is random.  A stimulation list that begins with a stimulation on pair would look as follows (with bold indicating stimulation):\n**1 - 2** | 3 - 4 | **5 - 6** | 7 - 8 | **9 - 10** | 11 - 12\n#### To Note\n* The iEEG recordings are labeled either \"monopolar\" or \"bipolar.\"  The monopolar recordings are referenced (typically a mastoid reference), but should always be re-referenced before analysis.  The bipolar recordings are referenced according to a paired scheme indicated by the accompanying bipolar channels tables.\n* Each subject has a unique montage of electrode locations.  MNI and Talairach coordinates are provided when available.\n* Recordings done with the Blackrock system are in units of 250 nV, while recordings done with the Medtronic system are estimated through testing to have units of 0.1 uV.  We have completed the scaling to provide values in V.\n#### Contact\nFor questions or inquiries, please contact sas-kahana-sysadmin@sas.upenn.edu.","recording_modality":["ieeg"],"senior_author":"Michael J. Kahana","sessions":["0","1","2"],"size_bytes":24202629465,"source":"openneuro","study_design":null,"study_domain":null,"tasks":["catFR2"],"timestamps":{"digested_at":"2026-04-22T12:27:46.966618+00:00","dataset_created_at":"2024-09-16T20:43:53.335Z","dataset_modified_at":"2024-09-16T21:26:48.000Z"},"total_files":51,"storage":{"backend":"s3","base":"s3://openneuro.org/ds005491","raw_key":"dataset_description.json","dep_keys":["CHANGES","README","participants.json","participants.tsv"]},"tagger_meta":{"config_hash":"3557b68bca409f28","metadata_hash":"317db1cf79854c01","model":"openai/gpt-5.2","tagged_at":"2026-04-07T09:32:40.872789+00:00"},"tags":{"pathology":["Unknown"],"modality":["Visual"],"type":["Clinical/Intervention"],"confidence":{"pathology":0.6,"modality":0.85,"type":0.7},"reasoning":{"few_shot_analysis":"Most similar few-shot by cognitive paradigm is the digit span dataset (few-shot: \"EEG, pupillometry... digit span task\"), which is labeled Type=Memory because participants encode and maintain/retrieve sequential verbal items. This dataset likewise uses an explicit episodic memory paradigm (categorized free recall: study words + distractor + free recall), so the few-shot convention suggests Type=Memory. However, unlike the digit span few-shot, this dataset explicitly includes intracranial electrical stimulation during encoding, which pushes the purpose toward an intervention-style manipulation (few-shot conventions use Type=Clinical/Intervention for datasets centered on clinical/biomarker/intervention contexts, e.g., dementia resting-state and Parkinson cohorts). For Modality, multiple few-shots show that the modality is based on stimulus input channel (e.g., visual discrimination -> Visual), so visually presented words map to Visual.","metadata_analysis":"Key task and stimulus facts: (1) Memory paradigm: \"participants studying a list of words... and then freely recalling the words from the just-presented list in any order.\" (2) Visual input channel: \"a list of words, presented visually one at a time\". (3) Intervention/manipulation: \"This study contains open-loop electrical stimulation of the brain during encoding.\" and \"Stimulation is delivered... with locations chosen in the hippocampus and entorhinal cortex.\" Population/diagnosis is not explicitly named; only context: \"data was collected at clinical sites across the country\" and recordings are \"intracranial electrophysiological recordings\".","paper_abstract_analysis":"No useful paper information.","evidence_alignment_check":"Pathology: Metadata SAYS: \"intracranial electrophysiological recordings\" and \"collected at clinical sites\" but does not state a recruiting diagnosis (e.g., epilepsy). Few-shot pattern SUGGESTS that many iEEG datasets are from epilepsy patients, but that is an inference not an explicit fact here. ALIGN/CONFLICT: Partial conflict (pattern suggests Epilepsy, metadata does not confirm). Decision: follow explicit-metadata rule -> Pathology=Unknown.\n\nModality: Metadata SAYS: \"words, presented visually\". Few-shot pattern SUGGESTS Visual when stimuli are screen-presented (e.g., visual discrimination task -> Visual). ALIGN/CONFLICT: Align. Decision: Modality=Visual.\n\nType: Metadata SAYS: \"categorized free recall task\" with study+\"distractor\"+\"freely recalling\" (a classic episodic memory construct) and also \"open-loop electrical stimulation... during encoding\". Few-shot pattern SUGGESTS Memory for explicit encoding/recall paradigms (digit span labeled Memory), but also uses Clinical/Intervention when the dataset is organized around a clinical/interventional manipulation. ALIGN/CONFLICT: Mixed—memory task aligns with Memory label; stimulation manipulation aligns with Clinical/Intervention. Decision: choose Clinical/Intervention because stimulation is a central experimental factor (stimulation lists, parameters, timing) rather than incidental metadata.","decision_summary":"Top-2 Pathology candidates: (A) Unknown — supported by lack of explicit diagnosis; only \"clinical sites\" and \"intracranial\" are given. (B) Epilepsy — plausible given common iEEG recruitment, but not stated. Alignment status: conflict between inference and explicitness -> select Unknown. Confidence justified: no direct diagnostic quote.\n\nTop-2 Modality candidates: (A) Visual — supported by \"words, presented visually one at a time\". (B) Other — possible because stimulation is present, but stimulation is not a sensory stimulus modality. Alignment status: aligns with few-shot convention -> select Visual. Confidence justified by explicit visual-stimulus quote(s).\n\nTop-2 Type candidates: (A) Clinical/Intervention — supported by \"open-loop electrical stimulation of the brain during encoding\" plus detailed stimulation assignment/parameters. (B) Memory — supported by \"categorized free recall\" and \"freely recalling the words\". Alignment status: mixed; select Clinical/Intervention because intervention is a primary manipulation at encoding. Confidence justified by explicit stimulation + free-recall quotes but with a close runner-up (Memory)."}},"nemar_citation_count":0,"computed_title":"Categorized Free Recall with Open-Loop Stimulation at Encoding","nchans_counts":[{"val":126,"count":5},{"val":64,"count":5},{"val":88,"count":4},{"val":93,"count":3},{"val":85,"count":3},{"val":133,"count":2},{"val":104,"count":2},{"val":155,"count":2},{"val":116,"count":2},{"val":163,"count":2},{"val":113,"count":2},{"val":177,"count":1},{"val":68,"count":1},{"val":78,"count":1},{"val":96,"count":1},{"val":146,"count":1},{"val":92,"count":1},{"val":124,"count":1},{"val":127,"count":1},{"val":80,"count":1},{"val":119,"count":1},{"val":115,"count":1},{"val":112,"count":1},{"val":70,"count":1},{"val":16,"count":1},{"val":128,"count":1},{"val":72,"count":1},{"val":130,"count":1},{"val":110,"count":1},{"val":14,"count":1}],"sfreq_counts":[{"val":500.0,"count":39},{"val":1600.0,"count":6},{"val":999.0,"count":4},{"val":1000.0,"count":2}],"stats_computed_at":"2026-04-22T23:16:00.309676+00:00","total_duration_s":168035.4053893894,"canonical_name":null,"name_confidence":0.62,"name_meta":{"suggested_at":"2026-04-14T10:18:35.343Z","model":"openai/gpt-5.2 + openai/gpt-5.4-mini + deterministic_fallback"},"name_source":"canonical","author_year":"Herrema2024_Categorized"}}