Linking DMN connectivity to episodic memory capacity: what can we learn from patients with medial temporal lobe damage?

Cornelia McCormick; Andrea B Protzner; Alexander J Barnett; Melanie Cohn; Taufik A Valiante; Mary Pat McAndrews

doi:10.1016/j.nicl.2014.05.008

Linking DMN connectivity to episodic memory capacity: what can we learn from patients with medial temporal lobe damage?

Neuroimage Clin. 2014 May 16:5:188-96. doi: 10.1016/j.nicl.2014.05.008. eCollection 2014.

Authors

Cornelia McCormick¹, Andrea B Protzner², Alexander J Barnett³, Melanie Cohn³, Taufik A Valiante⁴, Mary Pat McAndrews⁵

Affiliations

¹ Krembil Neuroscience Center & Toronto Western Research Institute, University Health Network, Toronto, ON, Canada ; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
² Department of Psychology, University of Calgary, Calgary, AB, Canada.
³ Krembil Neuroscience Center & Toronto Western Research Institute, University Health Network, Toronto, ON, Canada ; Department of Psychology, University of Toronto, Toronto, ON, Canada.
⁴ Krembil Neuroscience Center & Toronto Western Research Institute, University Health Network, Toronto, ON, Canada ; Department of Neurosurgery, University of Toronto, Toronto, ON, Canada.
⁵ Krembil Neuroscience Center & Toronto Western Research Institute, University Health Network, Toronto, ON, Canada ; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada ; Department of Psychology, University of Toronto, Toronto, ON, Canada.

Abstract

Computational models predict that focal damage to the Default Mode Network (DMN) causes widespread decreases and increases of functional DMN connectivity. How such alterations impact functioning in a specific cognitive domain such as episodic memory remains relatively unexplored. Here, we show in patients with unilateral medial temporal lobe epilepsy (mTLE) that focal structural damage leads indeed to specific patterns of DMN functional connectivity alterations, specifically decreased connectivity between both medial temporal lobes (MTLs) and the posterior part of the DMN and increased intrahemispheric anterior-posterior connectivity. Importantly, these patterns were associated with better and worse episodic memory capacity, respectively. These distinct patterns, shown here for the first time, suggest that a close dialogue between both MTLs and the posterior components of the DMN is required to fully express the extensive repertoire of episodic memory abilities.

Keywords: Episodic memory; Functional connectivity patterns; Medial temporal lobe epilepsy; Mediation; Structural damage.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Association Learning / physiology
Brain Mapping
Epilepsy, Temporal Lobe / physiopathology*
Female
Humans
Image Processing, Computer-Assisted
Magnetic Resonance Imaging
Male
Memory, Episodic*
Middle Aged
Nerve Net / physiopathology*
Temporal Lobe / physiopathology*
Young Adult

Grants and funding

97891/Canadian Institutes of Health Research/Canada