Real-time fMRI neurofeedback reduces auditory hallucinations and modulates resting state connectivity of involved brain regions: Part 2: Default mode network -preliminary evidence

Abstract

Auditory hallucinations (AHs) are one of the most distressing symptoms of schizophrenia (SZ) and are often resistant to medication. Imaging studies of individuals with SZ show hyperactivation of the default mode network (DMN) and the superior temporal gyrus (STG). Studies in SZ show DMN hyperconnectivity and reduced anticorrelation between DMN and the central executive network (CEN). DMN hyperconnectivity has been associated with positive symptoms such as AHs while reduced DMN anticorrelations with cognitive impairment. Using real-time fMRI neurofeedback (rt-fMRI-NFB) we trained SZ patients to modulate DMN and CEN networks. Meditation is effective in reducing AHs in SZ and to modulate brain network integration and increase DMN anticorrelations. Consequently, patients were provided with meditation strategies to enhance their abilities to modulate DMN/CEN. Results show a reduction of DMN hyperconnectivity and increase in DMNCEN anticorrelation. Furthermore, the change in individual DMN connectivity significantly correlated with reductions in AHs. This is the first time that meditation enhanced through rt-fMRI-NFB is used to reduce AHs in SZ. Moreover, it provides the first empirical evidence for a direct causal relation between meditation enhanced rt-fMRI-NFB modulation of DMNCEN activity and post-intervention modulation of resting state networks ensuing in reductions in frequency and severity of AHs.

Keywords: Auditory hallucinations; Default mode network; Mindfulness meditation; Real-time neurofeedback; Schizophrenia.

Figure 1.. Schematic representation of the experimental procedure.

A) Baseline resting state (RS-pre) scan. B) Functional Localization of the default mode network (DMN in blue) and the central executive network (CEN in red). C) rt-fMRI feedback process showing the online monitoring of brain states while performing “mental noting”. If rt-fMRI analysis resulted in a Positive Diametric Activity (PDA) score (red shadowing) the central white dot of the feedback display moved up towards the red circle. When a negative PDA score was triggered (blue shadowing), the central white dot moved down towards the blue circle. D) Post rt-fMRI resting state.

Figure 2:. Regions showing a significant change in resting state functional connectivity (rsFC).

rsFC with Medial Prefrontal Cortex (MPFC) following either (A) real-time Default Mode Network (rtDMN) neurofeedback or (B) real-time Somato Motor Cortex (rtSMC) neurofeedback. Boxplots show the pre-to-post change functional connectivity z-scores for MPFC and Posterior Cingulate Cortex (PCC), right dorsolateral prefrontal cortex (rDLPFC) and anterior cingulate cortex (ACC) and MPFC-rDLPFC connectivity z-scores. All thresholds, cluster threshold p<0.05 FWE corrected. Green circles show in MPFC seed region of interest (ROIs) used to determine the rsFC analysis.

Figure 3:. Correlation of change in auditory hallucinations and change in STG-MPFC connectivity.

Significant reduction (Pre-to-Post) of auditory hallucinations AHs (Δ AHs Score) with a reduction (Pre-to-Post) in STG-MPFC connectivity (Δ STG/MPFC) for resting state following real-time Default Mode Network neurofeedback.