title: Similar patterns of neural activity predict memory function during encoding and retrieval.
abstract: Neural networks that span the medial temporal lobe (MTL), prefrontal cortex, and posterior cortical regions are essential to episodic memory function in humans. Encoding and retrieval are supported by the engagement of both distinct neural pathways across the cortex and common structures within the medial temporal lobes. However, the degree to which memory performance can be determined by neural processing that is common to encoding and retrieval remains to be determined. To identify neural signatures of successful memory function, we administered a delayed free-recall task to 187 neurosurgical patients implanted with subdural or intraparenchymal depth electrodes. We developed multivariate classifiers to identify patterns of spectral power across the brain that independently predicted successful episodic encoding and retrieval. During encoding and retrieval, patterns of increased high frequency activity in prefrontal, MTL, and inferior parietal cortices, accompanied by widespread decreases in low frequency power across the brain predicted successful memory function. Using a cross-decoding approach, we demonstrate the ability to predict memory function across distinct phases of the free-recall task. Furthermore, we demonstrate that classifiers that combine information from both encoding and retrieval states can outperform task-independent models. These findings suggest that the engagement of a core memory network during either encoding or retrieval shapes the ability to remember the past, despite distinct neural interactions that facilitate encoding and retrieval.
authors.affiliation: Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Kragel
authors.affiliation: Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA.
authors.forename: Youssef
authors.initials: Y
authors.lastname: Ezzyat
authors.affiliation: Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sperling
authors.affiliation: Department of Radiology, Thomas Jefferson University Hospital, Philadelphia PA 19107, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Gorniak
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester MN 55905, USA.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Worrell
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester MN 55905, USA.
authors.forename: Brent M
authors.initials: BM
authors.lastname: Berry
authors.affiliation: Department of Neurosurgery, Emory School of Medicine, Atlanta GA 30322, USA.
authors.forename: Cory
authors.initials: C
authors.lastname: Inman
authors.affiliation: Department of Neurosurgery, University of Texas Southwestern, Dallas TX 75390, USA.
authors.forename: Jui-Jui
authors.initials: JJ
authors.lastname: Lin
authors.affiliation: Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Davis
authors.affiliation: Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Sandhitsu R
authors.initials: SR
authors.lastname: Das
authors.affiliation: Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia PA 19104, USA.
authors.forename: Joel M
authors.initials: JM
authors.lastname: Stein
authors.affiliation: Department of Neurology, Dartmouth Medical Center, Lebanon NH 03756, USA.
authors.forename: Barbara C
authors.initials: BC
authors.lastname: Jobst
authors.affiliation: Surgical Neurology Branch, National Institutes of Health, Bethesda MD 20814, USA.
authors.forename: Kareem A
authors.initials: KA
authors.lastname: Zaghloul
authors.affiliation: Department of Neurosurgery, Columbia University Medical Center, New York NY 10032, USA.
authors.forename: Sameer A
authors.initials: SA
authors.lastname: Sheth
authors.affiliation: Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Rizzuto
authors.affiliation: Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA. Electronic address: kahana@psych.upenn.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kahana
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D011939:Mental Recall / Q000502:physiology*; D008959:Models, Neurological; D009434:Neural Pathways / Q000502:physiology
keywords: Episodic memory; Free recall; MVPA; iEEG