Effects of Mindfulness-Based Interventions on Gray Matter Volume in Patients with Opioid Dependence.

INTRODUCTION: Recently, several mindfulness-based programs showed promising clinical effects in the treatment of psychiatric disorders including substance use disorders. However, very little is known about the effects of mindfulness-based interventions (MBIs) on brain structure in such patients. METHODS: This study aimed to detect changes in gray matter volume (GMV) in opioid-dependent patients receiving MBI during their first month of treatment. Thirty patients were assigned to either 3 weeks of MBI (n = 16) or treatment as usual (TAU, n = 14) and were investigated using structural magnetic resonance imaging before and after treatment. Longitudinal pipeline of the Computational Anatomy Toolbox for SPM (CAT12) was used to detect significant treatment-related changes over time. The identified GMV changes following treatment were related to clinically relevant measures such as impulsivity, distress tolerance, and mindfulness. RESULTS: After treatment, increased mindfulness scores were found in individuals receiving MBI compared to TAU. In the MBI group, there were also significant differences with respect to distress tolerance and impulsivity. Effects on mindfulness, distress tolerance, and impulsivity were also found in the TAU group. Longitudinal within-group analysis revealed increased left anterior insula GMV in individuals receiving MBI. Anterior insula volume increase was associated with decreased impulsivity levels. In the TAU group, significant GMV changes were found in the right lingual gyrus and right entorhinal cortex. DISCUSSION/CONCLUSION: MBI can yield significant clinical effects during early abstinence from opioid dependence. MBI is particularly associated with increased insula GMV, supporting an important role of this region in the context of MBI-induced neural changes.

Multimodal MRI data fusion reveals distinct structural, functional and neurochemical correlates of heavy cannabis use.

Heavy cannabis use (HCU) is frequently associated with a plethora of cognitive, psychopathological and sensorimotor phenomena. Although HCU is frequent, specific patterns of abnormal brain structure and function underlying HCU in individuals presenting without cannabis-use disorder or other current and life-time major mental disorders are unclear at present. This multimodal magnetic resonance imaging (MRI) study examined resting-state functional MRI (rs-fMRI) and structural MRI (sMRI) data from 24 persons with HCU and 16 controls. Parallel independent component analysis (p-ICA) was used to examine covarying components among grey matter volume (GMV) maps computed from sMRI and intrinsic neural activity (INA), as derived from amplitude of low-frequency fluctuations (ALFF) maps computed from rs-fMRI data. Further, we used JuSpace toolbox for cross-modal correlations between MRI-based modalities with nuclear imaging derived estimates, to examine specific neurotransmitter system changes underlying HCU. We identified two transmodal components, which significantly differed between the HCU and controls (GMV: p = 0.01, ALFF p = 0.03, respectively). The GMV component comprised predominantly cerebello-temporo-thalamic regions, whereas the INA component included fronto-parietal regions. Across HCU, loading parameters of both components were significantly associated with distinct HCU behavior. Finally, significant associations between GMV and the serotonergic system as well as between INA and the serotonergic, dopaminergic and µ-opioid receptor system were detected. This study provides novel multimodal neuromechanistic insights into HCU suggesting co-altered structure/function-interactions in neural systems subserving cognitive and sensorimotor functions.

Mindfulness-based therapy modulates default-mode network connectivity in patients with opioid dependence.

Recently, mindfulness-based programs have shown promising clinical effects in the treatment of substance-use disorders (SUD). While several studies linked mindfulness to decreased default mode network (DMN) connectivity in meditators, only a few studies investigated its effects in patients with SUD. This study aimed to detect changes in DMN connectivity in opiate dependent patients receiving mindfulness based therapy (MBT) during their first month of treatment. Data from 32 patients that were assigned to MBT or treatment as usual (TAU) groups was investigated using resting-state functional MRI at 1.5 T before and after four weeks of treatment. Independent Component Analysis was used to investigate distinct (anterior vs. posterior) DMN subsystems. Connectivity changes after treatment were related to measures of impulsivity, distress tolerance and mindfulness. Increased mindfulness scores after treatment were found in patients receiving MBT compared to TAU. Within the anterior DMN, decreased right inferior frontal cortical connectivity was detected in patients who received MBT compared to TAU. In addition, within the MBT-group decreased right superior frontal cortex connectivity was detected after treatment. Inferior frontal cortex function was significantly associated with mindfulness measures. The data suggest that MBT can be useful during abstinence from opiates. In opiate-dependent patients distinct functional connectivity changes within the DMN are associated with MBT.

Mindfulness-based interventions modulate structural network strength in patients with opioid dependence.

Mindfulness-based interventions (MBI) are increasingly used in the treatment of patients with mental disorders, in particular in individuals presenting with affective disorders or in patients exhibiting abnormal levels of impulsive behavior. MBI have been also offered to patients with substance use disorders, where such treatment options may yield considerable clinical effects. Neural effects associated with MBI have been increasingly acknowledged, but is unknown whether MBI exert specific effects on brain structure in patients with substance use disorders. In this study, we investigated 19 inpatients with opioid dependence receiving treatment-as-usual (TAU, n = 9) or additional MBI (n = 10). Structural magnetic resonance imaging data were acquired before and after four weeks of treatment. Source-based morphometry was used to investigate modulation of structural networks after treatment. Both treatment modalities led to significant clinical improvement. Patients receiving MBI showed a significant change in distress tolerance levels. An increase in bilateral striatal/insular and prefrontal/cingulate network strength was found in patients receiving MBI compared to individuals receiving TAU. Prefrontal/cingulate cortical network strength was associated with impulsivity levels. These findings suggest that MBI can have a recognizable role in treatment of substance use disorders and that neural effects of MBI may be captured in terms of frontostriatal structural network change.

Brain structure in preclinical Huntington's disease: a multi-method approach.

BACKGROUND: Structural magnetic resonance imaging (MRI) of the brain could be a powerful tool for discovering early biomarkers in clinically presymptomatic carriers of the Huntington's disease gene mutation (preHD). So far, structural changes have been found mainly in preHD approaching the estimated motor onset of the disease (i.e., less than 15 years from onset), whereas structural findings in preHD far from the estimated motor onset have been inconclusive. OBJECTIVES: The aims of this study were to investigate the sensitivity of different methodological approaches to structural data in far-from-onset preHD (mean estimated time to motor onset = 21.4 years) and to explore the relationship between brain structure, clinical variables and cognition. METHODS: High-resolution MRI data at 3 T were obtained from 20 preHD individuals and 20 healthy participants and subsequently analyzed using voxel-based morphometry (VBM), cortical surface modeling and subcortical segmentation analysis techniques. RESULTS: VBM analyses did not reveal significant between-group differences, whereas cortical surface modeling and subcortical segmentation analyses showed significant regional cortical thinning and striatal changes in preHD compared to controls. Significant correlations were found between striatal structure, estimated time to motor onset and executive performance, whereas cortical changes were not significantly correlated with these parameters. CONCLUSION: These data suggest that a combined methodological approach to structural MRI data could increase the sensitivity for detecting subtle neurobiological changes in early preHD. As consistently shown across different methods, the association between striatal structure and clinical measures supports the notion that changes in striatal volume could represent a more robust marker of disease progression than cortical changes.

Cortical activation during a pitch discrimination task in tinnitus patients and controls--an fMRI study.

Chronic subjective tinnitus has been associated with aberrant activation of cortical areas involved in the perception of auditory information. This leads to the hypothesis that neural correlates of altered auditory perception may be found in tinnitus patients using functional magnetic resonance imaging. To study brain activation patterns due to acoustic stimulation in a pitch discrimination task, 6 tinnitus patients and 6 age-matched controls were investigated. Tones were presented binaurally at 5 beeps/s with three different frequencies in a block design. Using Statistical Parametrical Mapping, we found activation of secondary auditory areas in both groups. Furthermore, controls showed activation of the right-hemispheric anterior insula, whereas the middle frontal gyrus, putamen and left-hemispheric insula were activated in tinnitus patients. In the between-group analysis, activation of the caudate nucleus, superior frontal gyrus (Brodmann area 8) and cingular cortex was more pronounced in patients than in controls suggesting the perception of auditory inputs in a more emotional context in our patient group compared to controls.

Evaluation of a novel event-related parametric fMRI paradigm investigating prefrontal function.

While prefrontal pathology is considered to be a core feature in schizophrenia, evidence from functional magnetic resonance imaging (fMRI) studies using cognitive activation tasks is less reliable in terms of demonstrating 'functional hypofrontality'. Here we present a new event-related fMRI paradigm specifically developed to assess the gradual recruitment of brain areas during verbal working memory (WM) by taking into account theoretical and pragmatic limitations of activation tools used in clinical cognitive neuroscience. We studied 15 healthy subjects during the performance of a WM task that required the manipulation of verbal information. We observed a robust recruitment of frontoparietal areas with increasing load. Comparing the two highest loads, we found further bilateral striatal activation. A median split into good and poor performers revealed significant positive correlations of prefrontal activation in the group of good performers and correlations with striato-thalamic activation in the poor-performance group, thus emphasizing a crucial role of subcortical structures for performance in highly demanding WM tasks. Because it induces a robust bilateral frontoparietal activation pattern along with performance-related effects of cerebral activation, we consider this paradigm to be suitable to test prefrontal function in schizophrenic patients during the manipulation of items held in WM.