Functional MRI neurofeedback training on connectivity between two regions induces long-lasting changes in intrinsic functional network.

Fukuda Megumi,Mitsuo Kawato,Hiroshi Imamizu,Ayumu Yamashita

doi:10.3389/fnhum.2015.00160

Abstract

Motor or perceptual learning is known to influence functional connectivity between brain regions and induce short-term changes in the intrinsic functional networks revealed as correlations in slow blood-oxygen-level dependent (BOLD) signal fluctuations. However, no cause-and-effect relationship has been elucidated between a specific change in connectivity and a long-term change in global networks. Here, we examine the hypothesis that functional connectivity (i.e., temporal correlation between two regions) is increased and preserved for a long time when two regions are simultaneously activated or deactivated. Using the connectivity-neurofeedback training paradigm, subjects successfully learned to increase the correlation of activity between the lateral parietal and primary motor areas, regions that belong to different intrinsic networks and negatively correlated before training under the resting conditions. Furthermore, whole-brain hypothesis-free analysis as well as functional network analyses demonstrated that the correlation in the resting state between these areas as well as the correlation between the intrinsic networks that include the areas increased for at least 2 months. These findings indicate that the connectivity-neurofeedback training can cause long-term changes in intrinsic connectivity and that intrinsic networks can be shaped by experience-driven modulation of regional correlation.

Highlights

Spatial and temporal correlations in spontaneous brain activity are generated by the underlying connectivity of brain networks (Ringach, 2009)
We examined the robustness of these results with respect to the threshold setting for correlation values: the clusters in lateral parietal (LP) and posterior cingulate cortex (PCC) were consistently found at threshold ranges of −0.3 ≤ r ≤ −0.1 only in the neurofeedback training group, while no significant cluster could be found at a threshold of r < −0.25 in either the sham-feedback or the tapping-imagery group
We hypothesized that positively correlated activations of two regions evoked by repeated experiences induces a long-term increase in their functional connectivity, which is the temporal correlation values within intrinsic networks

Summary

Introduction

Spatial and temporal correlations in spontaneous brain activity are generated by the underlying connectivity of brain networks (Ringach, 2009). Connectivity-neurofeedback strikingly similar to networks estimated by spatial ICA of the resting state fMRI (Smith et al, 2009; Laird et al, 2011). These studies indicate that the repertoire of functional networks is continuously and dynamically activated even during “rest” and that the dynamics represent the brain architecture. We propose and directly test the hypothesis that spontaneous brain activity is shaped in an experience-driven manner, where the temporal correlation at rest between two brain regions is increased when they are simultaneously activated or deactivated. We assume that an absolute value of correlation reflects the strength of functional connectivity, e.g., a large negative (r ≈ −1.0) or positive (r ≈ +1.0) correlation means a strong connectivity while a correlation near zero (r ≈ 0.0) means a weak connectivity

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