The nested hierarchical model of self and its non-relational vs relational posttraumatic manifestation: an fMRI meta-analysis of emotional processing.

Different kinds of traumatic experiences like natural catastrophes vs. relational traumatic experiences (e.g., sex/physical abuse, interpersonal partner violence) are involved in the development of the self and PTSD psychopathological manifestations. Looking at a neuroscience approach, it has been proposed a nested hierarchical model of self, which identifies three neural-mental networks: (i) interoceptive; (ii) exteroceptive; (iii) mental. However, it is still unclear how the self and its related brain networks might be affected by non-relational vs relational traumatic experiences. Departing from this background, the current study aims at conducting a meta-analytic review of task-dependent fMRI studies (i.e., emotional processing task) among patients with PTSD due to non-relational (PTSD-NR) and relational (PTSD-R) traumatic experiences using two approaches: (i) a Bayesian network meta-analysis for a region-of-interest-based approach; (ii) a coordinated-based meta-analysis. Our findings suggested that the PTSD-NR mainly recruited areas ascribed to the mental self to process emotional stimuli. Whereas, the PTSD-R mainly activated regions associated with the intero-exteroceptive self. Accordingly, the PTSD-R compared to the PTSD-NR might not reach a higher symbolic capacity to process stimuli with an emotional valence. These results are also clinically relevant in support of the development of differential treatment approaches for non-relational vs. relational PTSD.

On the interplay between state-dependent reconfigurations of global signal correlation and BOLD fluctuations: An fMRI study.

BACKGROUND: The dynamics of global, state-dependent reconfigurations in brain connectivity are yet unclear. We aimed at assessing reconfigurations of the global signal correlation coefficient (GSCORR), a measure of the connectivity between each voxel timeseries and the global signal, from resting-state to a stop-signal task. The secondary aim was to assess the relationship between GSCORR and blood-oxygen-level-dependent (BOLD) activations or deactivation across three different trial-conditions (GO, STOP-correct, and STOP-incorrect). METHODS: As primary analysis we computed whole-brain, voxel-wise GSCORR during resting-state (GSCORR-rest) and stop-signal task (GSCORR-task) in 107 healthy subjects aged 21-50, deriving GSCORR-shift as GSCORR-task minus GSCORR-rest. GSCORR-tr and trGSCORR-shift were also computed on the task residual time series to quantify the impact of the task-related activity during the trials. To test the secondary aim, brain regions were firstly divided in one cluster showing significant task-related activation and one showing significant deactivation across the three trial conditions. Then, correlations between GSCORR-rest/task/shift and activation/deactivation in the two clusters were computed. As sensitivity analysis, GSCORR-shift was computed on the same sample after performing a global signal regression and GSCORR-rest/task/shift were correlated with the task performance. RESULTS: Sensory and temporo-parietal regions exhibited a negative GSCORR-shift. Conversely, associative regions (ie. left lingual gyrus, bilateral dorsal posterior cingulate gyrus, cerebellum areas, thalamus, posterolateral parietal cortex) displayed a positive GSCORR-shift (FDR-corrected p < 0.05). GSCORR-shift showed similar patterns to trGSCORR-shift (magnitude increased) and after global signal regression (magnitude decreased). Concerning BOLD changes, Brodmann area 6 and inferior parietal lobule showed activation, while posterior parietal lobule, cuneus, precuneus, middle frontal gyrus showed deactivation (FDR-corrected p < 0.05). No correlations were found between GSCORR-rest/task/shift and beta-coefficients in the activation cluster, although negative correlations were observed between GSCORR-task and GO/STOP-correct deactivation (Pearson rho=-0.299/-0.273; Bonferroni-p < 0.05). Weak associations between GSCORR and task performance were observed (uncorrected p < 0.05). CONCLUSION: GSCORR state-dependent reconfiguration indicates a reallocation of functional resources to associative areas during stop-signal task. GSCORR, activation and deactivation may represent distinct proxies of brain states with specific neurofunctional relevance.

Psychological dissociation and temporal integration/segregation across the senses: An experimental study.

There are no studies that have experimentally tested how temporal integration/segregation of sensory inputs might be linked to the emergence of dissociative experiences and alterations of emotional functioning. Thirty-six participants completed 3 sensory integration tasks. Psychometric thresholds were estimated as indexes of temporal integration/segregation processes. We collected self-report measures of pre-task trait levels of dissociation, as well as pre- post-task changes in both dissociation and emotionality. An independent sample of 21 subjects completed a control experiment administering the Attention Network Test. Results showed: (i) a significant increase of dissociative experiences after the completion of sensory integration tasks, but not after the ANT task; (ii) that subjective thresholds predicted the emergence of dissociative states; (iii) temporal integration efforts affected positive emotionality, which was explained by the extent of task-dependent dissociative states. The present findings reveal that dissociation could be understood in terms of an imbalance between "hyper-segregation" and "hyper-integration" processes.

Intrinsic neural timescales mediate the cognitive bias of self - temporal integration as key mechanism.

Our perceptions and decisions are not always objectively correct as they are featured by a bias related to our self. What are the behavioral, neural, and computational mechanisms of such cognitive bias? Addressing this yet unresolved question, we here investigate whether the cognitive bias is related to temporal integration and segregation as mediated by the brain's Intrinsic neural timescales (INT). Using Signal Detection Theory (SDT), we operationalize the cognitive bias by the Criterion C as distinguished from the sensitivity index d'. This was probed in a self-task based on morphed self- and other faces. Behavioral data demonstrate clear cognitive bias, i.e., Criterion C. That was related to the EEG-based INT as measured by the autocorrelation window (ACW) in especially the transmodal regions dorsolateral prefrontal cortex (dlPFC) and default-mode network (DMN) as distinct from unimodal visual cortex. Finally, simulation of the same paradigm in a large-scale network model shows high degrees of temporal integration of temporally distinct inputs in CMS/DMN and dlPFC while temporal segregation predominates in visual cortex. Together, we demonstrate a key role of INT-based temporal integration in CMS/DMN and dlPFC including its relation to the brain's uni-transmodal topographical organization in mediating the cognitive bias of our self.

The self and our perception of its synchrony - Beyond internal and external cognition.

The self is the core of our mental life which connects one's inner mental life with the external perception. Since synchrony is a key feature of the biological world and its various species, what role does it play for humans? We conducted a large-scale psychological study (n = 1072) combining newly developed visual analogue scales (VAS) for the perception of synchrony and internal and external cognition complemented by several psychological questionnaires. Overall, our findings showed close connection of the perception of synchrony of the self with both internal (i.e., body and cognition) and external (i.e., others, environment/nature) synchrony being associated positively with adaptive and negatively with maladaptive traits of self. Moreover, we have demonstrated how external (i.e., life events like the COVID-19 pandemic) variables modulate the perception of the self's internal-external synchrony. These findings suggest how synchrony with self plays a central role during times of uncertainty.

Dissociative Dimensions and Their Implications for Emotional Dysregulation Underlying Borderline Personality Disorder Features.

ABSTRACT: Emotion dysregulation is considered a core feature of borderline personality disorder (BPD). The role of dissociation in BPD has been discussed from different perspectives. Nevertheless, implications of dissociation for BPD features are not clear. The current study estimated mediation effects of dissociative dimensions on the relationships between several emotion regulation strategies (ERSs) and BPD features among 281 adults recruited from the general population. The online survey administered a comprehensive self-report battery for the assessment of maladaptive and adaptive ERSs together with dissociative dimensions. Borderline personality disorder features were also self-report screened. Results showed significant indirect effects of dissociation on the relationships between ERSs and BPD features. Dissociation was a full mediator of the relationship between deficits with problem-solving skills and BPD criteria. The study confirmed that emotion dysregulation is a core feature of BPD and that the dissociative dimensions should be included as relevant maladaptive mechanisms sustaining BPD emotional difficulties.

Neural responses to emotional stimuli across the dissociative spectrum: Common and specific mechanisms.

AIM: Departing from existing neurobiological models of dissociation, the current study aims at conducting a quantitative meta-analytic review of neural responses to emotional stimuli among individuals ascribed to the dissociative spectrum (DS). Accordingly, the study explored common and specific brain mechanisms across borderline personality disorder, conversion/somatoform disorders, posttraumatic stress disorder, posttraumatic stress disorder related to repeated interpersonal traumatic experiences, and dissociative disorders. METHODS: The meta-analysis included studies that administered emotional stimuli during functional magnetic resonance imaging acquisition among individuals included in the DS. There were two conducted meta-analytic procedures: (i) a Bayesian network meta-analysis for a region-of-interest-based approach; and (ii) robust voxel-based approach. RESULTS: Forty-four independent studies were included for a total of 1384 individuals (DS = 741 patients). The network meta-analysis showed specific patterns of neural activity considering an extended brain network involved in emotion regulation for each condition ascribed to the DS. The voxel-based meta-analysis highlighted an increased activity of dorsal anterior cingulate cortex as a common neurological signature of the DS. CONCLUSION: The common neural feature of the DS captures an implicit appraisal of emotion-eliciting stimuli as threatening and/or noxious for mental and physical integrity of the individual together with painful subjective experiences associated with physiological emotional reactions. Specific brain responses across the DS suggested the engagement in different mechanisms to address emotional stimuli, including implicit avoidance reactions and attempts to overcontrol of affective states together with a disruption of integrative processes of emotional mind-body features.

Attachment anxiety, reflective functioning and well-being as predictors of burn-out and psychological distress among psychotherapists: A longitudinal study.

OBJECTIVE: This study aims to longitudinally investigate the effects of individual's factors on subsequent burn-out/psychological distress in a sample of mental health practitioners, testing if higher attachment anxiety and avoidance and lower reflective functioning (i.e., certainty and uncertainty of mental states) and well-being at baseline may lead to a greater psychological distress and burn-out 1 year later. METHODS: The sample consisted of 40 experienced psychotherapists (females: 72.5%; mean age: 47.40 ± 9.48 years) who completed a battery of questionnaires at baseline and 1 year later. Statistical analyses were conducted with Bayesian multiple linear regressions. RESULTS: Greater attachment anxiety and certainty about mental states and lower individual's well-being at baseline predicted greater burn-out 1 year later. Similarly, greater attachment anxiety and lower individual's well-being at baseline predicted psychological distress at 1 year follow-up. Of note, uncertainty of mental states and avoidant attachment were not associated with outcomes. CONCLUSION: These findings suggest that the levels of burn-out and psychological distress among psychotherapists may be alleviated with interventions targeting attachment insecurity, specific aspects of reflective functioning (i.e., certainty about mental states) and well-being.

An integrative perspective on the role of touch in the development of intersubjectivity.

Touch concerns a fundamental component of sociality. In this review, we examine the hypothesis that somatomotor development constitutes a crucial psychophysiological element in the ontogeny of intersubjectivity. An interdisciplinary perspective is provided on how the communication channel of touch contributes to the sense of self and extends to the social self. During gestation, the transformation of random movements into organized sequences of actions with sensory consequences parallels the development of the brain's functional architecture. Brain subsystems shaped by the coordinated activity of somatomotor circuits to support these first body-environment interactions are the first brain functional arrangements to develop. We propose that tactile self-referring behaviour during gestation constitutes a prototypic mode of interpersonal exchange that supports the subsequent development of intersubjective exchange. The reviewed research suggests that touch constitutes a pivotal bodily experience that in early stages builds and later filters self-other interactions. This view is corroborated by the fact that aberrant social-affective touch experiences appear fundamentally associated with attachment anomalies, interpersonal trauma, and personality disorders. Given the centrality of touch for the development of intersubjectivity and for psychopathological conditions in the social domain, dedicated research is urged to elucidate the role of touch in the evolution of subjective self-other coding.

The self and its internal thought: In search for a psychological baseline.

Self-consciousness is neuronally associated with the brain's default mode network as its "neuronal baseline" while, psychologically the self is characterized by different thought modes and dynamics. We here raise the question whether they reflect the "psychological baseline" of the self. We investigate the psychological relationship of the self with thought modes (rumination, reflection) and mind-wandering dynamics (spontaneous, deliberate), as well as with depressive symptomatology. Our findings show a relationship between self-consciousness and i) mind-wandering dynamics, and ii) thought functional modes, in their respective forms. At the same time, self-consciousness is more related to spontaneous mind-wandering than deliberate and to rumination than reflection. Furthermore, iii) rumination acts as a mediator between self-consciousness and spontaneous mind-wandering dynamics; and iv) the relationship between high levels of self-consciousness and depressive symptoms is mediated by ruminative modes and spontaneous mind-wandering dynamics. Together, these findings support the view of the self as "psychological baseline".

Slow and Powerless Thought Dynamic Relates to Brooding in Unipolar and Bipolar Depression.

INTRODUCTION: Depression can be characterized by rumination that is featured by spontaneity and perseveration of internally oriented thoughts. At the same time, depressed subjects complain about abnormal slowness and lack of power/energy in their thoughts, suggesting abnormal "thought dynamics." The relationship between rumination and thought dynamics in depression remains unclear, though. METHOD: We investigated thought dynamics and rumination in healthy control, major depressive disorder (MDD), and depressed bipolar disorder (BD) subjects. The dynamics in the spontaneous shift between internally and externally oriented thoughts were measured by a novel method of continuous experience sampling whose time series was subjected to power and frequency analyses. Subjects filled out the Beck Depression Inventory-II and Ruminative Response Scale questionnaires to evaluate current depressive symptoms and ruminative responses to negative affect. The methods used to analyze data included χ2, Pearson correlation, ANOVA, and partial correlation. RESULTS: Our main findings are: (i) increased number and longer duration of internally oriented thought contents in MDD and BD; (ii) reduced thought dynamics with slower frequency (calculated in Hz) and decreased power (power spectral density) in shifting between internally and externally oriented thoughts, especially in MDD and, less strongly, in BD subjects; and (iii) power spectral density as a dimension of thought dynamics is related to brooding rumination with depression severity explaining high degrees of their variance. CONCLUSION: Our results show slow frequency and low power in the internal-external thought dynamic of acute MDD and depressed BD. Together with its close relation to depression severity and rumination, our findings highlight the key importance of abnormal dynamics on the cognitive level of depression.

What COVID-19 tells us about the self: The deep intersubjective and cultural layers of our brain.

The COVID-19 crisis is affecting our sense of self and touches upon our existential fears. This extends to the self-other relationship, as there is both being infected and infecting the other. What does this pandemic crisis tell us about our self and relatedness, its cultural differences, and how these are rooted in the brain's relation to the world? First, we discuss the psychological and neuronal features of self and self-other relation and how they are rooted in a deeper layer of the brain's neural activity complementing its cognitive surface layer. Second, we demonstrate cultural differences of Eastern and Western concepts of the self (i.e., independency and interdependency) and how these reflect the manifestation of the brain's neuro-social and neuro-ecological alignment. Finally, we highlight the intersubjective and cultural nature of the self and its surface in the COVID-19 crisis. Discussing various lines of empirical data showing the brain's intimate alignment to both social and ecological environmental contexts, our results support the assumption of the brain's deep layer features by laying bare a continuum of different degrees of neuro-social and neuro-ecological alignment. This entails a two-stage model of self with neuro-social-ecological and psychological levels that extends the previously suggested basis model of self-specificity. We conclude that the current pandemic shows the importance of the deeper intersubjective and cultural layers of both the self and brain; their neglect can be life-threatening for the self and others and, paradoxically, might reduce, rather than enlarge, the self's sense of freedom and independence.

Beneath the surface: hyper-connectivity between caudate and salience regions in ADHD fMRI at rest.

Attention-Deficit/Hyperactivity Disorder (ADHD) comprises disturbances in attention, emotional regulation, and reward-related processes. In spite of the active efforts in researching neurofunctional correlates of these symptoms, how the activity of subcortical regions-such as basal ganglia-is related to ADHD has yet to be clarified. More specifically, how age may influence the critical changes observed in functional dynamics from childhood to adulthood remains relatively unexplored. We hence selected five core subcortical regions (amygdala, caudate, putamen, pallidum and hippocampus) as regions of interest from the previous literature, measuring their whole-brain voxel-wise rsFC in a sample of 95 ADHD and 90 neurotypical children and adolescents aged from 7 to 18. The only subcortical structure showing significant differences in rsFC was the caudate nucleus. Specifically, we measured increased rsFC with anterior cingulate and right insula, two mesolimbic regions pertaining to the Salience Network. The degree of hyper-rsFC positively correlated with ADHD symptomatology, and showed different patterns of evolution in ADHD vs neurotypical subjects. Finally, the rsFC scores allowed a fair discrimination of the ADHD group (Area Under the Curve ≥ 0.7). These findings shed further light on the fundamental role covered by subcortical structures in ADHD pathogenesis and neurodevelopment, providing new evidence to fill the gap between neurofunctional and clinical expressions of ADHD.

Spontaneous Brain Activity Predicts Task-Evoked Activity During Animate Versus Inanimate Touch.

The spontaneous activity of the brain is characterized by an elaborate temporal structure with scale-free properties as indexed by the power law exponent (PLE). We test the hypothesis that spontaneous brain activity modulates task-evoked activity during interactions with animate versus inanimate stimuli. For this purpose, we developed a paradigm requiring participants to actively touch either animate (real hand) or inanimate (mannequin hand) stimuli. Behaviorally, participants perceived the animate target as closer in space, temporally more synchronous with their own self, and more personally relevant, compared with the inanimate. Neuronally, we observed a modulation of task-evoked activity by animate versus inanimate interactions in posterior insula, in medial prefrontal cortex, comprising anterior cingulate cortex, and in medial superior frontal gyrus. Among these regions, an increased functional connectivity was shown between posterior insula and perigenual anterior cingulate cortex (PACC) during animate compared with inanimate interactions and during resting state. Importantly, PLE during spontaneous brain activity in PACC correlated positively with PACC task-evoked activity during animate versus inanimate stimuli. In conclusion, we demonstrate that brain spontaneous activity in PACC can be related to the distinction between animate and inanimate stimuli and thus might be specifically tuned to align our brain with its animate environment.

The extent of dissociation in borderline personality disorder: A meta-analytic review.

Several authors have studied dissociation within the borderline personality disorder (BPD) population and postulated 3 dissociative subgroups. Conversely, other authors suggest that dissociation may play a central role in the development of trauma-related disorders and specifically in BPD. Nevertheless, the role of dissociation in BPD seems to be controversial. Our aim is to perform a meta-analytic review of the literature to evaluate the extent of dissociation in BPD compared to other psychopathological disorders to clarify its role in this specific condition. Ten eligible studies resulted in a total of 2,035 subjects. Results show that levels of dissociation are higher in BPD than in other psychiatric disorders in general, although this difference is moderate and the heterogeneity of effect sizes is large. In particular, individuals with BPD seem to show higher levels of dissociation than those with several psychiatric and personality disorders but not dissociative disorders or posttraumatic stress disorder. These findings support the fact that dissociation is not specifically a core feature of BPD and, in addition, sustain the existence of a continuum of severity within the psychiatric population. Nevertheless, the current work has several limitations related to the paucity of studies included, the heterogeneity of control groups, their clear definition, and the statistical robustness of the results. In addition, our conclusions require future research in order to explain the role of different forms of dissociation and their etiological factors among the psychiatric population. Eventually, we invite clinicians and researchers to systematically evaluate dissociation in order to reach a better diagnosis for a more specific treatment indication.

A novel analysis of interoceptive underpinnings of anxious psychopathology in COVID-19 survivors.

INTRODUCTION: SARS-CoV-2 affects brain, body, and their interchange. We investigated interoceptive mechanisms in COVID-19 survivors focusing on their potential link with psychopathology and inflammatory biomarkers. METHODS: We assessed interoceptive accuracy (IAc) and time-perceiving (TA) skills of 57 COVID-19 survivors one month after hospital discharge through, respectively, a heartbeats perception task and a time duration task. Each participant was assessed about his interoceptive awareness (IAw) through Multidimensional Assessment of Interoceptive Awareness questionnaire (MAIA) and then, screened for post-traumatic (Impact of Events Scale - IES-R), anxious (State-Trait Anxiety Inventory - STAI-Y1) and depressive (Zung Self-Rating Depression Scale - ZSDS; Beck Depression Inventory - BDI-13) symptoms. Biomarkers of inflammation (platelet count, PC; mean platelet volume, MPV and systemic immune-inflammation index, SII) were obtained in a subsample of 40 survivors by a blood sampling conducted at admission and discharge time from the hospital. Correlational, GLM, GLMZ, and mediation analyses were performed. RESULTS: IAc did not correlate with TA confirming the reliability of interoceptive measure. IAc positively predicts MAIA's Trusting subscale and negatively predicts anxious psychopathology which fully mediates the effect of IAc on Trusting.PC at hospital admission predicts anxiety at one month after recovery. Again, a higher decrease of SII during hospitalization predicts higher IAc skill and lower anxiety state at one month. The link between SII change and anxiety is fully mediated by IAc. CONCLUSIONS: Our results unveil a potential key role of interoception and brain-body interchange in the exacerbation and maintenance of anxiety psychopathology in COVID-19 survivors.

Antecedents and risk factors for borderline personality disorder: Etiopathogenic models based on a multi-level meta-analysis.

BACKGROUND: Empirically-based developmental psychopathology approach identified three domains involved in the emergence of borderline personality disorder (BPD): i) underlying liabilities to develop psychopathology (i.e., early patterns of internalizing and externalizing manifestations); ii) invalidating relational experiences (e.g., childhood traumatic experiences, maladaptive parenting, problematic peer relationships); iii) regulatory mechanisms of emotions and behaviors. Nevertheless, no studies have quantitatively summarized empirical findings concerning how and to what extent these domains might be temporally associated to the emergence of BPD features from adolescence to adulthood. METHODS: The current multi-level meta-analysis included 106 studies (N = 86,871 participants) assessing the role of previously mentioned antecedents and risk factors for BPD. RESULTS: The analysis showed moderate effect sizes capturing temporal associations between early internalizing/externalizing psychopathological manifestations, different invalidating relational experiences, emotion/behavior regulation processes with later BPD features. The effect sizes of these domains were not statistically different from each other. CONCLUSION: This evidence supports a transactional developmental model of BPD. Consistently, the emergence of BPD could be viewed in the light of dynamic interplays between an underlying liability to psychopathology and invalidating relational experiences across different stages of development, which are progressively reinforced through increasing alterations of emotion and behavior regulation mechanisms.

The noise in our brain: A systematic review and meta-analysis of neuroimaging and signal-detection studies on source monitoring in psychosis.

OBJECTIVES: Noisy thoughts or perceptions are characteristics of psychosis (PSY) and, they are deeply related to source monitoring (SM) - the ability to discriminate the origin of internal/external experiences. METHODS: This MOOSE, PRISMA-compliant meta-analysis compared SM performances in PSY compared to healthy controls (HC) focusing on signal-to-noise discrimination in order to: i) test whether neuroimaging procedures (fMRI/EEG) might be a group-specific source of noise for SM; ii) compare error- and accuracy-based indexes; iii) to meta-analyze signal-detection measures (i.e., discrimination index and response bias); iv) to determine the best index capturing SM deficits in psychosis. We conducted a 3-level meta-analysis for each aim to estimate pooled effect-sizes (Cohen's d). SM type, source discrimination and stimulus modality were used as meta-regressors. Heterogeneity (I2), publication bias (Egger's test) and multiple comparisons (Bonferroni correction) were considered. RESULTS: Sixteen neuroimaging, 44 error/accuracy-based behavioral and 7 signal-detection trials were included (2297 PSY, age range = 18.78-52.6; 1745 HC, age range = 21.1-53.3). The noise generated by neuroimaging procedures slightly influenced error, but not accuracy. Accuracy-based (d = -0.83), but not error-based, indexes showed significant and large SM impairments in PSY compared to HC. Overall SM performance differences between PSY and HC were larger in discrimination index (d = -0.65) and accuracy (d = -0.61), followed by response bias (d = -0.59, ns) and error-based (d = 0.35) indexes. CONCLUSION: Although both accuracy and discrimination indexes differentiate patients with PSY from HC, discrimination index is more reliable and may better capture the bi-directional nature of the internal/external source confusion.

Topographic-dynamic reorganisation model of dreams (TRoD) - A spatiotemporal approach.

Dreams are one of the most bizarre and least understood states of consciousness. Bridging the gap between brain and phenomenology of (un)conscious experience, we propose the Topographic-dynamic Re-organization model of Dreams (TRoD). Topographically, dreams are characterized by a shift towards increased activity and connectivity in the default-mode network (DMN) while they are reduced in the central executive network, including the dorsolateral prefrontal cortex (except in lucid dreaming). This topographic re-organization is accompanied by dynamic changes; a shift towards slower frequencies and longer timescales. This puts dreams dynamically in an intermediate position between awake state and NREM 2/SWS sleep. TRoD proposes that the shift towards DMN and slower frequencies leads to an abnormal spatiotemporal framing of input processing including both internally- and externally-generated inputs (from body and environment). In dreams, a shift away from temporal segregation to temporal integration of inputs results in the often bizarre and highly self-centric mental contents as well as hallucinatory-like states. We conclude that topography and temporal dynamics are core features of the TroD, which may provide the connection of neural and mental activity, e.g., brain and experience during dreams as their "common currency".

Ongoing Brain Activity and Its Role in Cognition: Dual versus Baseline Models.

What is the role of the brain's ongoing activity for cognition? The predominant perspectives associate ongoing brain activity with resting state, the default-mode network (DMN), and internally oriented mentation. This triad is often contrasted with task states, non-DMN brain networks, and externally oriented mentation, together comprising a "dual model" of brain and cognition. In opposition to this duality, however, we propose that ongoing brain activity serves as a neuronal baseline; this builds upon Raichle's original search for the default mode of brain function that extended beyond the canonical default-mode brain regions. That entails what we refer to as the "baseline model." Akin to an internal biological clock for the rest of the organism, the ongoing brain activity may serve as an internal point of reference or standard by providing a shared neural code for the brain's rest as well as task states, including their associated cognition. Such shared neural code is manifest in the spatiotemporal organization of the brain's ongoing activity, including its global signal topography and dynamics like intrinsic neural timescales. We conclude that recent empirical evidence supports a baseline model over the dual model; the ongoing activity provides a global shared neural code that allows integrating the brain's rest and task states, its DMN and non-DMN, and internally and externally oriented cognition.