Large-scale network integration in the human brain tracks temporal fluctuations in memory encoding performance

• Main Authors: Ruedeerat Keerativittayayut, Ryuta Aoki, Mitra Taghizadeh Sarabi, Koji Jimura, Kiyoshi Nakahara
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2018-06-01
• Series: eLife
• Subjects: episodic memory; encoding; large-scale brain networks; time-varying functional connectivity; graph analysis; fMRI
• Online Access: https://elifesciences.org/articles/32696

Although activation/deactivation of specific brain regions has been shown to be predictive of successful memory encoding, the relationship between time-varying large-scale brain networks and fluctuations of memory encoding performance remains unclear. Here, we investigated time-varying functional connectivity patterns across the human brain in periods of 30–40 s, which have recently been implicated in various cognitive functions. During functional magnetic resonance imaging, participants performed a memory encoding task, and their performance was assessed with a subsequent surprise memory test. A graph analysis of functional connectivity patterns revealed that increased integration of the subcortical, default-mode, salience, and visual subnetworks with other subnetworks is a hallmark of successful memory encoding. Moreover, multivariate analysis using the graph metrics of integration reliably classified the brain network states into the period of high (vs. low) memory encoding performance. Our findings suggest that a diverse set of brain systems dynamically interact to support successful memory encoding.