Extensions and Mechanisms of Mindfulness‐based Cognitive Therapy: A Review of the Evidence

Mindfulness‐based cognitive therapy (MBCT) was originally developed to prevent depressive relapse and recurrence and has also been widely extended to new patient populations and target problems over the last 14 years. We provide a comprehensive review of this literature, examining the strength of the evidence base for specific populations and target problems and identifying questions for future research to address. Specifically, we review studies addressing the use of MBCT for depressive disorders (prevention of depressive relapse and treatment of residual and current depressive symptoms), the use of MBCT in the treatment or management of other mental disorders (bipolar disorder, anxiety disorders, mixed anxiety and depression symptoms, disordered eating, personality disorders, and psychosis), and the use of MBCT in behavioural medicine contexts. Additionally, we discuss the extension of MBCT during specific developmental periods, like childhood, pregnancy and post‐partum, and adult caregiving, and, finally, we address the use of MBCT among clinical health‐care providers. In the second section, we review hypothesised mechanisms of change in MBCT and reflect on implications for theories of how MBCT works in the application to various patient populations and target problems. We also consider research addressing active ingredients and what is known about the “dosage” of meditation practice. We conclude with a summary of recommendations for future research.     

Effects of an early intervention on maternal post-traumatic stress symptoms and the quality of mother–infant interaction: The case of preterm birth

Preterm birth may represent a traumatic situation for both parents and a stressful situation for the infant, potentially leading to difficulties in mother–infant relationships. This study aimed to investigate the impact of an early intervention on maternal posttraumatic stress symptoms, and on the quality of mother–infant interactions, in a sample of very preterm infants and their mothers. Half of the very preterm infants involved in the study (n = 26) were randomly assigned to a 3-step early intervention program (at 33 and 42 weeks after conception and at 4 months’ corrected age). Both groups of preterm infants (with and without intervention) were compared to a group of full-term infants. The impact of the intervention on maternal posttraumatic stress symptoms was assessed 42 weeks after conception and when the infants were 4 and 12 months of age. The impact of the intervention on the quality of mother–infant interactions was assessed when the infants were 4 months old. Results showed a lowering of mothers’ posttraumatic stress symptoms between 42 weeks and 12 months in the group of preterm infants who received the intervention. Moreover, an enhancement in maternal sensitivity and infant cooperation during interactions was found at 4 months in the group with intervention. In the case of a preterm birth, an early intervention aimed at enhancing the quality of the mother–infant relationship can help to alleviate maternal post-traumatic stress symptoms and may have a positive impact on the quality of mother–infant interactions.     

Decision-making deficit of a patient with axonal damage after traumatic brain injury

Patients with traumatic brain injury (TBI) were reported to have difficulty making advantageous decisions, but the underlying deficits of the network of brain areas involved in this process were not directly examined. We report a patient with TBI who demonstrated problematic behavior in situations of risk and complexity after cerebral injury from a traffic accident. The Iowa gambling task (IGT) was used to reveal his deficits in the decision-making process. To examine underlying deficits of the network of brain areas, we examined T1-weighted structural MRI, diffusion tensor imaging (DTI) and Tc-ECD SPECT in this patient. The patient showed abnormality in IGT. DTI-MRI results showed a significant decrease in fractional anisotropy (FA) in the fasciculus between the brain stem and cortical regions via the thalamus. He showed significant decrease in gray matter volumes in the bilateral insular cortex, hypothalamus, and posterior cingulate cortex, possibly reflecting Wallerian degeneration secondary to the fasciculus abnormalities. SPECT showed significant blood flow decrease in the broad cortical areas including the ventromedial prefrontal cortex (VM). Our study showed that the patient had dysfunctional decision-making process. Microstructural abnormality in the fasciculus, likely from the traffic accident, caused reduced afferent feedback to the brain, resulting in less efficient decision-making. Our findings support the somatic-marker hypothesis (SMH), where somatic feedback to the brain influences the decision-making process.     

Left-hemisphere activation is associated with enhanced vocal pitch error detection in musicians with absolute pitch

The ability to process auditory feedback for vocal pitch control is crucial during speaking and singing. Previous studies have suggested that musicians with absolute pitch (AP) develop specialized left-hemisphere mechanisms for pitch processing. The present study adopted an auditory feedback pitch perturbation paradigm combined with ERP recordings to test the hypothesis whether the neural mechanisms of the left-hemisphere enhance vocal pitch error detection and control in AP musicians compared with relative pitch (RP) musicians and non-musicians (NM). Results showed a stronger N1 response to pitch-shifted voice feedback in the right-hemisphere for both AP and RP musicians compared with the NM group. However, the left-hemisphere P2 component activation was greater in AP and RP musicians compared with NMs and also for the AP compared with RP musicians. The NM group was slower in generating compensatory vocal reactions to feedback pitch perturbation compared with musicians, and they failed to re-adjust their vocal pitch after the feedback perturbation was removed. These findings suggest that in the earlier stages of cortical neural processing, the right hemisphere is more active in musicians for detecting pitch changes in voice feedback. In the later stages, the left-hemisphere is more active during the processing of auditory feedback for vocal motor control and seems to involve specialized mechanisms that facilitate pitch processing in the AP compared with RP musicians. These findings indicate that the left hemisphere mechanisms of AP ability are associated with improved auditory feedback pitch processing during vocal pitch control in tasks such as speaking or singing.     

Functional cortical connectivity analysis of mental fatigue unmasks hemispheric asymmetry and changes in small-world networks

Changes in functional connectivity across mental states can provide richer information about human cognition than simpler univariate approaches. Here, we applied a graph theoretical approach to analyze such changes in the lower alpha (8–10 Hz) band of EEG data from 26 subjects undergoing a mentally-demanding test of sustained attention: the Psychomotor Vigilance Test. Behavior and connectivity maps were compared between the first and last 5 min of the task. Reaction times were significantly slower in the final minutes of the task, showing a clear time-on-task effect. A significant increase was observed in weighted characteristic path length, a measure of the efficiency of information transfer within the cortical network. This increase was correlated with reaction time change. Functional connectivity patterns were also estimated on the cortical surface via source localization of cortical activities in 26 predefined regions of interest. Increased characteristic path length was revealed, providing further support for the presence of a reshaped global topology in cortical connectivity networks under fatigue state. Additional analysis showed an asymmetrical pattern of connectivity (right > left) in fronto-parietal regions associated with sustained attention, supporting the right-lateralization of this function. Interestingly, in the fatigue state, significance decreases were observed in left, but not right fronto-parietal connectivity. Our results indicate that functional network organization can change over relatively short time scales with mental fatigue, and that decreased connectivity has a meaningful relationship with individual difference in behavior and performance.     

Regional and inter-regional theta oscillation during episodic novelty processing

Recent event-related potential (ERP) and functional magnetic resonance imaging (fMRI) studies suggest that novelty processing may be involved in processes that recognize the meaning of a novel sound, during which widespread cortical regions including the right prefrontal cortex are engaged. However, it remains unclear how those cortical regions are functionally integrated during novelty processing. Because theta oscillation has been assumed to have a crucial role in memory operations, we examined local and inter-regional neural synchrony of theta band activity during novelty processing. Fifteen right-handed healthy university students participated in this study. Subjects performed an auditory novelty oddball task that consisted of the random sequence of three types of stimuli such as a target (1000 Hz pure tone), novel (familiar environmental sounds such as dog bark, buzz, car crashing sound and so on), and standard sounds (950 Hz pure tone). Event-related spectra perturbation (ERSP) and the phase-locking value (PLV) were measured from human scalp EEG during task. Non-parametric statistical tests were applied to test for significant differences between stimulus novelty and stimulus targets in ERSP and PLV. The novelty P3 showed significant higher amplitude and shorter latency compared with target P3 in frontocentral regions. Overall, theta activity was significantly higher in the novel stimuli compared with the target stimuli. Specifically, the difference in theta power between novel and target stimuli was most significant in the right frontal region. This right frontal theta activity was accompanied by phase synchronization with the left temporal region. Our results imply that theta phase synchronization between right frontal and left temporal regions underlie the retrieval of memory traces for unexpected but familiar sounds from long term memory in addition to working memory retrieval or novelty encoding.     

Visual asymmetry revisited: Mind wandering preferentially disrupts processing in the left visual field

An emerging theory proposes that visual attention operates in parallel at two distinct time scales – a shorter one (<1 s) associated with moment-to-moment orienting of selective visuospatial attention, and a longer one (>10 s) associated with more global aspects of attention-to-task. Given their parallel nature, here we examined whether these comparatively slower fluctuations in task-related attention show the same visual field asymmetry – namely, a right visual field bias – as often reported for selective visual–spatial attention. Participants performed a target detection task at fixation while event-related potentials (ERP) time-locked to task-irrelevant visual probes presented in the left and right visual fields were recorded. At random intervals, participants were asked to report whether they were “on-task” or “mind wandering”. Our results demonstrated that sensory attenuation during periods of “mind wandering” relative to “on-task”, as measured by the visual P1 ERP component at electrodes sites contralateral to the stimulus, was only observed for probes presented in the left visual field. In contrast, the magnitude of sensory gain in the right visual field was insensitive to whether participants were “on-task” or “mind wandering”. Taken together, our results support the notion that task-related attention at longer time scales and spatial attention at shorter time scales affect the same underlying mechanism in visual cortex.     

The effect of methylphenidate on very low frequency electroencephalography oscillations in adult ADHD

Altered very low-frequency electroencephalographic (VLF-EEG) activity is an endophenotype of ADHD in children and adolescents. We investigated VLF-EEG case-control differences in adult samples and the effects of methylphenidate (MPH). A longitudinal case-control study was conducted examining the effects of MPH on VLF-EEG (.02–0.2 Hz) during a cued continuous performance task. 41 untreated adults with ADHD and 47 controls were assessed, and 21 cases followed up after MPH treatment, with a similar follow-up for 38 controls (mean follow-up = 9.4 months). Cases had enhanced frontal and parietal VLF-EEG and increased omission errors. In the whole sample, increased parietal VLF-EEG correlated with increased omission errors. After controlling for subthreshold comorbid symptoms, VLF-EEG case-control differences and treatment effects remained. Post-treatment, a time by group interaction emerged; VLF-EEG and omission errors reduced to the same level as controls, with decreased inattentive symptoms in cases. Reduced VLF-EEG following MPH treatment provides preliminary evidence that changes in VLF-EEG may relate to MPH treatment effects on ADHD symptoms; and that VLF-EEG may be an intermediate phenotype of ADHD. Further studies of the treatment effect of MPH in larger controlled studies are required to formally evaluate any causal link between MPH, VLF-EEG and ADHD symptoms.     

Strategic retrieval processing and the impact of knowing when a memory was first created

Retrieval orientation refers to a process where participants strategically alter how a memory cue is processed in response to different task demands. In the present study we explored whether retrieval orientation is influenced by knowing when an old stimulus was first encoded. Participants completed separate remember/know test blocks for old items from a recent delay (40 min) and old items from a remote delay (48 h). Manipulations at encoding ensured that performance levels were matched between these two blocks, thus avoiding confounds with differences in retrieval effort. Importantly, a third test block comprised old items from both delays randomly intermixed. As the nature of the old items varies unpredictably in the mixed block, it should not be possibly to adopt a specific retrieval orientation and the mixed block therefore acts as a control condition. Participants saw the words “mixed,” “recent” or “remote” prior to each test block. Comparing ERPs from the recent and remote blocks permitted an investigation of whether participants alter their retrieval orientation in response to the specific length of the retention interval. Comparing ERPs from the pure (recent and remote) test blocks to ERPs from the mixed block permitted an investigation of whether delay information per se led to differences in retrieval strategy. Analysis of the ERP data found no differences between the recent and remote blocks. However, ERPs from these pure blocks were significantly less positive than ERPs from the mixed block from 200 ms towards the end of the epoch. The findings suggest that the delay information was useful in a general sense and encouraged retrieval strategies distinct from those engaged in the mixed block. We speculate that such strategies might relate to whether or not the retrieval search is specific and constrained and/or whether processes that serve to reinstate the original encoding context are engaged.