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Neuroimage. 2017 Jul 15;155:60-71. doi: 10.1016/j.neuroimage.2017.03.042. Epub 2017 Apr 2.

Similar patterns of neural activity predict memory function during encoding and retrieval.

Author information

1
Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA.
2
Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA.
3
Department of Radiology, Thomas Jefferson University Hospital, Philadelphia PA 19107, USA.
4
Department of Neurology, Mayo Clinic, Rochester MN 55905, USA.
5
Department of Neurosurgery, Emory School of Medicine, Atlanta GA 30322, USA.
6
Department of Neurosurgery, University of Texas Southwestern, Dallas TX 75390, USA.
7
Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA.
8
Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia PA 19104, USA.
9
Department of Neurology, Dartmouth Medical Center, Lebanon NH 03756, USA.
10
Surgical Neurology Branch, National Institutes of Health, Bethesda MD 20814, USA.
11
Department of Neurosurgery, Columbia University Medical Center, New York NY 10032, USA.
12
Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA. Electronic address: kahana@psych.upenn.edu.

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.

KEYWORDS:

Episodic memory; Free recall; MVPA; iEEG

PMID:
28377210
PMCID:
PMC5789770
DOI:
10.1016/j.neuroimage.2017.03.042
[Indexed for MEDLINE]
Free PMC Article

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