Self-referential Thinking Research Articles

EEG dynamics of spontaneous stimulus-independent thoughts

ABSTRACTIn this study, we aimed to compare the oscillatory dynamics accompanying self-referential and non-self-referential stimulus-independent thoughts. Electroencephalograms were recorded in 30 healthy participants who were asked to press buttons classifying their spontaneous thoughts as self-referential or non-self-referential. EEG data were analyzed using independent component analysis in conjunction with dipole localization. Self-referential thoughts, as compared to non-self-referential thoughts, were accompanied by more pronounced decreases of theta, alpha, and beta spectral power in the anterior hub of the default-mode network, in the left lateral prefrontal, motor/somatosensory, and temporal cortices. These oscillatory dynamics are interpreted as a reflection of autobiographical memory retrieval intrinsic to self-referential thoughts.Abbreviations: BA: Brodmann area; BOLD: blood oxygenation level-dependent; DMN: default mode network; EEG: electroencephalogram; ERSP: event-related spectral perturbations; fMRI: functional magnetic resonance imaging; PCC: posterior cingulate cortex; PET: positron emission tomography; PFC: prefrontal cortex; SIT: stimulus-independent thought; WM: working memory.

White matter abnormalities predict residual negative self-referential thinking following treatment of late-life depression with escitalopram: A preliminary study

BackgroundNegative self-referential thinking is a common symptom of depression associated with poor treatment response. In late-life depression, white matter abnormalities may contribute to negative self-referential thoughts following antidepressant treatment. We investigated the association of fractional anisotropy (FA) in select regions of the negative valence system (NVS) with residual negative self-referential thoughts following treatment with escitalopram for late-life depression. MethodsThe participants were older adults with major depression and psychiatrically normal controls. Depressed participants received 12 weeks of treatment with escitalopram. To assess self-referential thinking, participants completed a Trait Adjective Task at baseline and at week 12. Baseline MRI scans included a diffusion imaging sequence for FA analyses. ResultsParticipants with late-life depression differed from controls on all performance measures of the Trait Adjective Task at baseline and at 12 weeks. Depressed participants endorsed fewer negative personality traits and more positive personality traits at week 12 compared to baseline. Lower FA in the dorsal anterior cingulate and in the uncinate fasciculus in depressed participants was correlated with residual negative self-referential thinking (e.g., more endorsed negative adjectives, fewer rejected negative adjectives) at treatment end. LimitationsThe sample size is modest so the findings are preliminary. FA analyses were restricted to predetermined regions. ConclusionsNegative self-referential thinking improved in depressed older adults following 12 weeks of treatment with escitalopram. Baseline FA in select white matter regions of the NVS was associated with residual negative self-referential thinking. These findings may help identify treatment targets for residual negative self-referential thoughts.

Examining the Decoupling Model of Equanimity in Mindfulness Training: An Intensive Experience Sampling Study

Although Buddhist thought and contemporary psychological science have theorized that equanimity may be a critical outcome and salutary mechanism of action of mindfulness, empirical evidence is limited. Eighty-two meditation-naive adults (52% female; Mage = 25.05 years, SD = 3.26 years) from the general community participated in a 3-week, six-session mindfulness training intervention. Prior to and then over the course of the intervention, in the contexts of daily living and mindfulness meditation, we collected 52 digital experience samples (2–3/day). Mixed-linear models permitted analysis of data much like 82 single-subject multiple-baseline experimental design data sets. The practice and cultivation of mindfulness states were associated with elevations in manifestations of equanimity (i.e., elevated willingness and decreased hedonic-based avoidance), which were robust to spontaneous subjective stress as well as experimentally evoked idiographic negative self-referential thoughts. Mindfulness may therefore function to decouple desire (wanting and not wanting) from the hedonic tone of experience (pleasant and unpleasant).

Psychotherapy of Depression as Neurobiological Process - Evidence from Neuroimaging

Research on neurobiological effects of psychotherapy in depression facilitates the improvement of treatment strategies. The cortico-limbic dysregulation model serves as a framework for numerous studies on neurobiological changes in depression. In this model, depression is described as hypoactivation of dorsal cortical brain regions in conjunction with hyperactivation of ventral paralimbic regions. This assumption has been supported by various studies of structural and functional brain abnormalities in depression. However, also regions not included in the original cortico-limbic dysregulation model, such as the dorsomedial prefrontal cortex, seem to play an important role in depression. Functional connectivity studies of depression have revealed an enhanced connectivity within the so-called default mode network which is involved in self-referential thinking. Studies also point to a normalization of limbic and cortical brain activity, especially in the anterior cingulate cortex, during psychotherapy. Some neurobiological markers like the activity of the anterior cingulate cortex, striatum and insula as well as hippocampal volume have been proposed to predict treatment response on a group-level. The activity of the anterior insula appears to be a candidate bio-marker for differential indication for psychotherapy or pharmacotherapy. The cortico-limbic dysregulation model and following research have inspired new forms of treatment for depression like deep brain stimulation of the subgenual anterior cingulate cortex, repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex, neurofeedback and attention training.

Why People Are Always Thinking about Themselves: Medial Prefrontal Cortex Activity during Rest Primes Self-referential Processing.

Humans have a tendency to think about themselves. What generates this self-focus? One clue may come from the observation that the same part of the brain that supports self-reflection-the medial pFC (MPFC/Brodmann's area 10 [BA 10])-also spontaneously engages by default whenever the brain is free from external demands to attention. Here, we test the possibility that the default tendency to engage MPFC/BA 10 primes self-referential thinking. Participants underwent fMRI while alternating between brief periods of rest and experimental tasks in which they thought about their own traits, another person's traits, or another location's traits. Greater default engagement in MPFC/BA 10 during momentary breaks preferentially facilitated task performance on subsequent self-reflection trials on a moment-to-moment basis. These results suggest that reflexively engaging MPFC/BA 10 by default may nudge self-referential thinking, perhaps explaining why humans think about themselves so readily.

The effect of transcranial direct current stimulation of the prefrontal cortex on implicit self-esteem is mediated by rumination after criticism

It has been proposed that a crucial link between cognitive (i.e., self-schemas) and biological vulnerability is prefrontal control. This is because decreased control leads to impaired ability to inhibit ruminative thinking after the activation of negative self-schemas. However, current evidence is mainly correlational. In the current experimental study we tested whether the effect of neurostimulation of the dorsolateral prefrontal cortex (DLPFC) on self-esteem is mediated by momentary ruminative self-referential thinking (MRST) after the induction of negative self-schemas by criticism. We used a single, sham-controlled crossover session of anodal transcranial Direct Current Stimulation (tDCS) applied to the left DLPFC (cathode over the right supraorbital region) in healthy female individuals. After receiving tDCS/sham stimulation, we measured MRST and exposed the participants to critical audio scripts, followed by another MRST measurement. Subsequently, all participants completed two Implicit Relational Assessment Procedures to implicitly measure actual and ideal self-esteem. Our behavioral data indicated a significant decrease in MRST after real but not sham tDCS. Moreover, although there was no immediate effect of tDCS on implicit self-esteem, an indirect effect was found through double mediation, with the difference in MRST from baseline to after stimulation and from baseline to after criticism as our two mediators. The larger the decrease of criticism induced MRST after real tDCS, the higher the level of actual self-esteem. Our results show that tDCS can influence cognitive processes such as rumination, and subsequently self-esteem, but only after the activation of negative self-schemas. Rumination and negative self-esteem characterize different forms of psychopathology, and these data expand our knowledge of the role of the prefrontal cortex in controlling these self-referential processes, and the mechanisms of action of tDCS.

Network basis of suicidal ideation in depressed adolescents

BackgroundSuicidal ideation rates rise precipitously in adolescence, contributing to risk for attempts. Although researchers are beginning to explore the brain basis of attempts in depressed adolescents, none have focused on the basis of ideation, which has implications for prevention. This study examined the association between intrinsic neural network coherence and the severity of suicidal ideation in depressed adolescents. MethodsForty adolescents diagnosed with Major Depressive Disorder were administered the Columbia-Suicide Severity Rating Scale and underwent resting-state fMRI. We quantified within-network coherence in the executive control (ECN), default mode (DMN), and salience (SN) networks, and in a non-relevant network consisting of noise signal. We associated coherence in each of these networks with the greatest lifetime severity of suicidal ideation experienced, covarying for motion, age of depression onset, and severity of current depressive and anxious symptoms. ResultsLower coherence in the left ECN, anterior DMN, and SN were independently associated with greater lifetime severity of suicidal ideation. When including all three significant networks and covariates in a single model, only the left ECN significantly predicted suicidal ideation. LimitationStudies with a larger sample size are needed to verify our findings. ConclusionsOur finding of hypoconnectivity in multiple networks extends emerging evidence for hypoconnectivity in adolescent suicidality and is consistent with theoretical conceptualizations of suicidal ideation as a complex set of cognitions associated with cognitive control, self-referential thinking, and processing salient information. While multiple networks could be targets for effective early interventions, those targeting ECN functionality (cognitive control) may be particularly beneficial.

Increased left prefrontal brain perfusion after MRI compatible tDCS attenuates momentary ruminative self-referential thoughts

BackgroundTranscranial direct current stimulation (tDCS) is a non-invasive electrical stimulation technique, assumed to influence cognition and emotional processing. Objective: However, it is unclear how tDCS influences spontaneous cognitive processes such as momentary self-referential thoughts on the neuronal level. MethodsForty healthy female volunteers participated in a single session sham-controlled crossover tDCS study while being in the MRI scanner. We measured brain perfusion (arterial spin labeling) just before and just after tDCS. Before and after the stimulation procedure, participants were scored on mood (visual analogue scales) and on the Momentary Ruminative Self-focus Inventory (MRSI). We performed a 1.5 mA, 20-min, anodal left dorsolateral prefrontal cortex, cathodal right supraorbital stimulation. ResultsOne sham-controlled tDCS session did not result in subjective mood changes. However, as compared to before, MRSI scores significantly decreased only after active tDCS. Regression analysis revealed that this reduction in momentary ruminative self-referential thoughts was related to tDCS-related increases in left prefrontal cortical perfusion. tDCS decreased momentary self-referential thoughts, which was associated with increasing perfusion in the left prefrontal cortex. ConclusionOur findings are in line with the hypothesis that tDCS of the DLPFC attenuates ruminative processes.

Absence of EEG correlates of self-referential processing depth in ALS.

Self-referential processing is a key cognitive process, associated with the serotonergic system and the default mode network (DMN). Decreased levels of serotonin and reduced activations of the DMN observed in amyotrophic lateral sclerosis (ALS) suggest that self-referential processing might be altered in patients with ALS. Here, we investigate the effects of ALS on the electroencephalography correlates of self-referential thinking. We find that electroencephalography (EEG) correlates of self-referential thinking are present in healthy individuals, but not in those with ALS. In particular, thinking about themselves or others significantly modulates the bandpower in the medial prefrontal cortex in healthy individuals, but not in ALS patients. This finding supports the view of ALS as a complex multisystem disorder which, as shown here, includes dysfunctional processing of the medial prefrontal cortex. It points towards possible alterations of self-consciousness in ALS patients, which might have important consequences for patients’ self-conceptions, personal relations, and decision-making.

Differential Effects of Word-Repetition Rate on Cognitive Defusion of Believability and Discomfort of Negative Self-Referential Thoughts Postintervention and at One-Month Follow-Up

Objective: The word repetition technique is used in acceptance and commitment therapy as a method of facilitating cognitive defusion from distressing thoughts. The present study conducted a randomised trial to manipulate the rate of word repetition and evaluate its impact on the efficacy of cognitive defusion. Method: Thirty-two participants repeated a self-chosen negative self-evaluative word for 30 seconds at the rates of one word per 0.5-, 1-, or 2-seconds. Visual analogue scales were used to measure the associated levels of believability and discomfort at pre- and immediately postrepetition, and 1 month later. Results: Both believability and discomfort were significantly reduced immediately after word repetition in the 0.5-seconds and 1-second conditions. There was a significantly greater reduction in Discomfort in the 1-second condition in comparison to the 2-second condition. The 1-second condition alone maintained significant reductions in both believability and discomfort at 1-month follow up. Conclusion: Differences in the cognitive defusion of distressing thoughts appear to be influenced by word repetition rate with repetition rates of one word per 0.5 and 1 seconds somewhat more effective for treating distressing private experiences associated with problem words.

Testosterone Effects on the Brain in Transgender Men.

Transgender individuals experience incongruence between their gender identity and birth-assigned sex. The resulting gender dysphoria (GD), which some gender-incongruent individuals experience, is theorized to be a consequence of atypical cerebral sexual differentiation, but support for this assertion is inconsistent. We recently found that GD is associated with disconnected networks involved in self-referential thinking and own body perception. Here, we investigate how these networks in trans men (assigned female at birth with male gender identity) are affected by testosterone. In 22 trans men, we obtained T1-weighted, diffusion-weighted, and resting-state functional magnetic resonance imaging scans before and after testosterone treatment, measuring cortical thickness (Cth), subcortical volumes, fractional anisotropy (FA), and functional connectivity. Nineteen cisgender controls (male and female) were also scanned twice. The medial prefrontal cortex (mPFC) was thicker in trans men than controls pretreatment, and remained unchanged posttreatment. Testosterone treatment resulted in increased Cth in the insular cortex, changes in cortico-cortical thickness covariation between mPFC and occipital cortex, increased FA in the fronto-occipital tract connecting these regions, and increased functional connectivity between mPFC and temporo-parietal junction, compared with controls. Concluding, in trans men testosterone treatment resulted in functional and structural changes in self-referential and own body perception areas.

Functional connectivity of resting-state, working memory and inhibition networks in perceived stress

Experimental imaging studies on the effects of acute stress have revealed functional changes in the amygdalae, hippocampi and medial frontal cortices. However, much less is known about the association between perceived stress and neurological function which may have implications for the development of stress related disorders. Participants completed a working-memory task and an inhibition task whilst undergoing a functional magnetic resonance imaging (fMRI) scan. Task related and resting-state fMRI data from 22 women and 24 men were analysed to investigate changes in task activations and functional connectivity associated with perceived stress over the past month. Analyses were stratified by gender due to gender differences in the stress response. Stress was associated with faster working memory response time in women, but not men. Stress was not associated with any differences in task activations in either gender. There were many significant associations between stress and connectivity: findings in women were consistent with increased emotional regulation; men exhibited decreases in connectivity between affective processing areas during the tasks and showed no relation between perceived stress and resting-state connectivity; very few of the within gender differences were significantly different between gender. Dysregulated connectivity between areas involved in the neural stress response and self-referential thoughts (e.g. the default mode network) suggests that perceived stress may have a subtle impact on cognitive processing and neural correlates.

Neural correlates of mindful self-awareness in mindfulness meditators and meditation-naïve subjects revisited

Mindful self-awareness is central to mindfulness meditation and plays a key role in its salutary effects. It has been related to decreased activation in cortical midline structures (CMS) and amygdala, and increased activation in somatosensory regions. However, findings in untrained individuals are contradictory, and scarce in experienced meditators.Using fMRI, we investigated experienced mindfulness meditators (LTM, n=21, average 4652 practice-hours) and matched meditation-naïve participants (MNP, n=19) during short periods of mindful self-awareness (FEEL) and self-referential thinking (THINK).We report somatosensory activations and decreases in CMS during FEEL for both groups, but significantly stronger decreases in prefrontal CMS in LTM. LTM further showed decreases in language-related and amygdala regions, but the latter was not significantly different between groups. Overall, higher activations in amygdala and mid-line regions during FEEL were related to levels of depressiveness.Neural patterns of mindful self-awareness emerge already in MNP but more pronounced in LTM. Specifically, meditation training might reduce self-reference and verbalization during mindful awareness. We further corroborate the suggested link between mindfulness and healthy self-related functions on the neural level. Longitudinal studies need to corroborate these findings.

Serotonergic modulation of resting state default mode network connectivity in healthy women.

The default mode network (DMN) plays a central role in intrinsic thought processes. Altered DMN connectivity has been linked to diminished cerebral serotonin synthesis. Diminished brain serotonin synthesis is further associated with a lack of impulse control and various psychiatric disorders. Here, we investigated the serotonergic modulation of intrinsic functional connectivity (FC) within the DMN in healthy adult females, controlling for the menstrual cycle phase. Eighteen healthy women in the follicular phase (aged 20-31 years) participated in a double-blind controlled cross-over study of serotonin depletion. Acute tryptophan depletion (ATD) and a balanced amino acid load (BAL), used as the control condition, were applied on two separate days of assessment. Neural resting state data using functional magnetic resonance imaging (fMRI) and individual trait impulsivity scores were obtained. ATD compared with BAL significantly reduced FC with the DMN in the precuneus (associated with self-referential thinking) and enhanced FC with the DMN in the frontal cortex (associated with cognitive reasoning). Connectivity differences with the DMN between BAL and ATD in the precentral gyrus were significantly correlated with the magnitude of serotonin depletion. Right medial frontal gyrus and left superior frontal gyrus connectivity differences with the DMN were inversely correlated with trait impulsivity. These findings partially deviate from previous findings obtained in males and underline the importance of gender-specific studies and controlling for menstrual cycle to further elucidate the mechanism of ATD-induced changes within intrinsic thought processes.

Association of Chronic Stress with Agency, Theory of Mind Function and Abstract Construal in Women

Stress disrupts the medial prefrontal cortex (PFC) networks required for consciousness, abstract construal, self-referential thinking, reward circuitry and theory-of-mind functions. We used stress assessment inventories to survey a cohort of 113 women for self-reported stress over a 5 - 10-year period. We identified two subsets of women consistently reporting either high (n = 21) or low (n = 24) stress over this period. These cohorts answered the eSAIL, REM and Apathy Evaluation Scale questionnaires. Significant differences were found between cohorts in apathy and REM scores, as well as in RD, self-agency and abstraction, but not in other subscales of the eSAIL.

Prestimulus default mode activity influences depth of processing and recognition in an emotional memory task.

Low self-referential thoughts are associated with better concentration, which leads to deeper encoding and increases learning and subsequent retrieval. There is evidence that being engaged in externally rather than internally focused tasks is related to low neural activity in the default mode network (DMN) promoting open mind and the deep elaboration of new information. Thus, reduced DMN activity should lead to enhanced concentration, comprehensive stimulus evaluation including emotional categorization, deeper stimulus processing, and better long-term retention over one whole week. In this fMRI study, we investigated brain activation preceding and during incidental encoding of emotional pictures and on subsequent recognition performance. During fMRI, 24 subjects were exposed to 80 pictures of different emotional valence and subsequently asked to complete an online recognition task one week later. Results indicate that neural activity within the medial temporal lobes during encoding predicts subsequent memory performance. Moreover, a low activity of the default mode network preceding incidental encoding leads to slightly better recognition performance independent of the emotional perception of a picture. The findings indicate that the suppression of internally-oriented thoughts leads to a more comprehensive and thorough evaluation of a stimulus and its emotional valence. Reduced activation of the DMN prior to stimulus onset is associated with deeper encoding and enhanced consolidation and retrieval performance even one week later. Even small prestimulus lapses of attention influence consolidation and subsequent recognition performance.

Dynamic Resting-State Functional Connectivity in Major Depression.

Major depressive disorder (MDD) is characterized by abnormal resting-state functional connectivity (RSFC), especially in medial prefrontal cortical (MPFC) regions of the default network. However, prior research in MDD has not examined dynamic changes in functional connectivity as networks form, interact, and dissolve over time. We compared unmedicated individuals with MDD (n=100) to control participants (n=109) on dynamic RSFC (operationalized as SD in RSFC over a series of sliding windows) of an MPFC seed region during a resting-state functional magnetic resonance imaging scan. Among participants with MDD, we also investigated the relationship between symptom severity and RSFC. Secondary analyses probed the association between dynamic RSFC and rumination. Results showed that individuals with MDD were characterized by decreased dynamic (less variable) RSFC between MPFC and regions of parahippocampal gyrus within the default network, a pattern related to sustained positive connectivity between these regions across sliding windows. In contrast, the MDD group exhibited increased dynamic (more variable) RSFC between MPFC and regions of insula, and higher severity of depression was related to increased dynamic RSFC between MPFC and dorsolateral prefrontal cortex. These patterns of highly variable RSFC were related to greater frequency of strong positive and negative correlations in activity across sliding windows. Secondary analyses indicated that increased dynamic RSFC between MPFC and insula was related to higher levels of recent rumination. These findings provide initial evidence that depression, and ruminative thinking in depression, are related to abnormal patterns of fluctuating communication among brain systems involved in regulating attention and self-referential thinking.

Evaluations of self-referential thoughts and their association with components of Acceptance and Commitment Therapy

Limited research has been carried out with respect to relationships among how individuals relate to thoughts and levels of cognitive fusion, experiential avoidance, psychological distress and mindfulness. Recent third-wave cognitive behavioral therapies such as Acceptance and Commitment Therapy (ACT) use techniques that focus less on changing the content of thoughts, and place more emphasis on changing the client's relationship to thoughts. For this reason, it is important to consider initial relations between the client's thoughts and the factors that ACT focuses on. The current study investigated associations among several ACT-consistent factors and how they relate to evaluations of positive and negative self-relevant thoughts. Seventy-nine participants completed ACT-consistent psychological measures and thought evaluation measures. The results indicated that ACT-consistent variables were associated with thought relations (i.e., believability, discomfort and willingness) rather than evaluations of content (i.e., negativity). Positive associations were observed among greater levels of psychological distress and psychological inflexibility (i.e., greater experiential avoidance and cognitive fusion). Mediation analysis identified believability of negative thoughts as a partially mediating factor in the predictive ability of mindfulness, experiential avoidance and cognitive fusion on psychological distress, with stronger negative thought believability positively associated with greater levels of psychological distress. The results are discussed in terms of the clinical implications of the relations observed.

Reduced neural differentiation between self-referential cognitive and emotional processes in women with borderline personality disorder

Borderline personality disorder (BPD) is associated with disturbed emotion regulation. Psychotherapeutic interventions using mindfulness elements have shown effectiveness in reducing clinical symptoms, yet little is known about their underlying neurobiology. In this functional magnetic resonance imaging (fMRI) study, 19 female BPD patients and 19 healthy controls were compared during mindful introspection, cognitive self-reflection and a neutral condition. The activation pattern in the right dorsomedial prefrontal cortex (DMPFC) in BPD patients was different from that in healthy subject when directing attention onto their emotions and bodily feelings in contrast to cognitively thinking about themselves. Mindful introspection compared with the neutral condition was associated with higher activations in bilateral motor/pre-motor regions, left inferior frontal gyrus (IFG), and left posterior cingulate cortex (PCC), while cognitive self-reflection activated the right motor and somatosensory cortex, extending into the right supramarginal gyrus (SMG) and superior temporal gyrus (STG) in BPD patients compared with the controls. Results indicate that self-referential cognitive and emotional processes are not clearly differentiated in BPD patients at the neurobiological level. In particular, altered neural mechanism underlying self-referential thinking may be related to some aspects of the typical emotion dysregulation in BPD. Current data support the finding that mindful self-focused attention is effective in regulating amygdala activity in BPD as well as in healthy subjects.

Functional brain networks involved in reality monitoring

Source monitoring refers to the recollection of variables that specify the context and conditions in which a memory episode was encoded. This process involves using the qualitative and quantitative features of a memory trace to distinguish its source. One specific class of source monitoring is reality monitoring, which involves distinguishing internally generated from externally generated information, that is, memories of imagined events from real events. The purpose of the present study was to identify functional brain networks that underlie reality monitoring, using an alternative type of source monitoring as a control condition. On the basis of previous studies on self-referential thinking, it was expected that a medial prefrontal cortex (mPFC) based network would be more active during reality monitoring than the control condition, due to the requirement to focus on a comparison of internal (self) and external (other) source information. Two functional brain networks emerged from this analysis, one reflecting increasing task-related activity, and one reflecting decreasing task-related activity. The second network was mPFC based, and was characterized by task-related deactivations in areas resembling the default-mode network; namely, the mPFC, middle temporal gyri, lateral parietal regions, and the precuneus, and these deactivations were diminished during reality monitoring relative to source monitoring, resulting in higher activity during reality monitoring. This result supports previous research suggesting that self-referential thinking involves the mPFC, but extends this to a network-level interpretation of reality monitoring.