Reconfiguration of Directed Functional Connectivity Among Neurocognitive Networks with Aging: Considering the Role of Thalamo-Cortical Interactions

Cereb Cortex. 2021 Mar 5;31(4):1970-1986. doi: 10.1093/cercor/bhaa334.

Abstract

A complete picture of how subcortical nodes, such as the thalamus, exert directional influence on large-scale brain network interactions across age remains elusive. Using directed functional connectivity and weighted net causal outflow on resting-state fMRI data, we provide evidence of a comprehensive reorganization within and between neurocognitive networks (default mode: DMN, salience: SN, and central executive: CEN) associated with age and thalamocortical interactions. We hypothesize that thalamus subserves both modality-specific and integrative hub role in organizing causal weighted outflow among large-scale neurocognitive networks. To this end, we observe that within-network directed functional connectivity is driven by thalamus and progressively weakens with age. Secondly, we find that age-associated increase in between CEN- and DMN-directed functional connectivity is driven by both the SN and the thalamus. Furthermore, left and right thalami act as a causal integrative hub exhibiting substantial interactions with neurocognitive networks with aging and play a crucial role in reconfiguring network outflow. Notably, these results were largely replicated on an independent dataset of matched young and old individuals. Our findings strengthen the hypothesis that the thalamus is a key causal hub balancing both within- and between-network connectivity associated with age and maintenance of cognitive functioning with aging.

Keywords: directed functional connectivity; healthy aging; multivariate Granger causality; salience network; thalamus; weighted net causal outflow.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Aging / physiology*
  • Aging / psychology*
  • Cerebral Cortex / diagnostic imaging
  • Cerebral Cortex / physiology*
  • Cognition / physiology*
  • Cohort Studies
  • Female
  • Humans
  • Magnetic Resonance Imaging / trends
  • Male
  • Middle Aged
  • Nerve Net / diagnostic imaging
  • Nerve Net / physiology*
  • Thalamus / diagnostic imaging
  • Thalamus / physiology*
  • Young Adult