Beyond the amygdala: Linguistic threat modulates peri-sylvian semantic access cortices

Functional connectivity in rumination: a systematic review of magnetic resonance imaging studies

INTRODUCTION

Rumination, defined as intrusive and repetitive thoughts in response to negative emotions, uncertainty, and inconsistency between goal and current situation, is a significant risk factor for depressive disorders. The rumination literature presents diverse findings on functional connectivity and shows heterogeneity in research methods. This systematic review seeks to integrate these findings and provide readers diverse perspectives.

METHOD

For this purpose, the literature on functional connectivity in rumination was reviewed according to the PRISMA guidelines. Regional connectivity and network connectivity results were scrutinized according to the presence of depression, research methods, and type of rumination. After screening 492 articles, a total of 36 studies were included.

RESULTS

The results showed that increased connectivity of the default mode network (DMN) was consistently reported. Other important findings include alterations in the connectivity between the DMN and the frontoparietal network and the salience network (SN) and impaired regulatory function of the SN. Region-level connectivity studies consistently show that increased connectivity between the posterior cingulate cortex and the prefrontal cortex is associated with rumination, which may cause the loss of control of the frontoparietal network over self-referential processes. We have seen that the number of studies examining brooding and reflective rumination as separate dimensions are relatively limited. Although there are overlaps between the connectivity patterns of the two types of rumination in these studies, it can be thought that reflective rumination is more associated with more increased functional connectivity of the prefrontal cortex.

CONCLUSIONS

Although there are many consistent functional connectivity outcomes associated with trait rumination, less is known about connectivity changes during state rumination. Relatively few studies have taken into account the subjective aspect of this thinking style. In order to better explain the relationship between rumination and depression, rumination induction studies during episode and remission periods of depression are needed.

Localized task-invariant emotional valence encoding revealed by intracranial recordings

The ability to distinguish between negative, positive and neutral valence is a key part of emotion perception. Emotional valence has conceptual meaning that supersedes any particular type of stimulus, although it is typically captured experimentally in association with particular tasks. We sought to identify neural encoding for task-invariant emotional valence. We evaluated whether high-gamma responses (HGRs) to visually displayed words conveying emotions could be used to decode emotional valence from HGRs to facial expressions. Intracranial electroencephalography was recorded from 14 individuals while they participated in two tasks, one involving reading words with positive, negative, and neutral valence, and the other involving viewing faces with positive, negative, and neutral facial expressions. Quadratic discriminant analysis was used to identify information in the HGR that differentiates the three emotion conditions. A classifier was trained on the emotional valence labels from one task and was cross-validated on data from the same task (within-task classifier) as well as the other task (between-task classifier). Emotional valence could be decoded in the left medial orbitofrontal cortex and middle temporal gyrus, both using within-task classifiers and between-task classifiers. These observations suggest the presence of task-independent emotional valence information in the signals from these regions.

Orienting to Different Dimensions of Word Meaning Alters the Representation of Word Meaning in Early Processing Regions

Conscious processing of word meaning can be guided by attention. In this event-related functional magnetic resonance imaging study in 22 healthy young volunteers, we examined in which regions orienting attention to two fundamental and generic dimensions of word meaning, concreteness versus valence, alters the semantic representations coded in activity patterns. The stimuli consisted of 120 nouns in written or spoken modality which varied factorially along the concreteness and valence axis. Participants performed a forced-choice judgement of either concreteness or valence. Rostral and subgenual anterior cingulate were strongly activated during valence judgement, and precuneus and the dorsal attention network during concreteness judgement. Task and stimulus type interacted in right posterior fusiform gyrus, left lingual gyrus, precuneus, and insula. In the right posterior fusiform gyrus and the left lingual gyrus, the correlation between the pairwise similarity in activity patterns evoked by words and the pairwise distance in valence and concreteness was modulated by the direction of attention, word valence or concreteness. The data indicate that orienting attention to basic dimensions of word meaning exerts effects on the representation of word meaning in more peripheral nodes, such as the ventral occipital cortex, rather than the core perisylvian language regions.

Infective Messages: Definitions, Processes, and Implications for Trauma, Identities, Internal Conflicts, Psychotherapy, and Research

BACKGROUND

Throughout life, individuals are bombarded by countless emotion-generating messages. Certain of these messages, for example, some insults, admonitions, rejections, challenges, or insightful declarations, can be viewed as "infective." Infective messages shock, puncture, adhere, disturb, and generate discernable host responses that assimilate, accommodate, or repel the intruding messages. Messages originating in one's own mind can stimulate psychological equivalents of autoimmune responses. Sometimes, these messages produce enduring psychological changes. Infective messages may traumatize, organize, or therapize. The aims of this article are to consider how infective messages a) relate to their messengers (vectors), structural characteristics, and recipient (host) factors; b) might contribute to trauma, personal identity formation, psychological conflicts, and emotional self-regulatory and cognitive heuristics; c) might inform the conduct of psychotherapy; and d) suggest future research.

METHODS

Clinical observations were augmented with selective literature reviews. These sources contributed to perspectives regarding how certain messages might become infective; contribute to trauma, complex aspects of identity formation, and inner conflict; and inform the conduct of psychotherapy.

RESULTS

Infective messages are commonly characterized by short, cogent communications emanating from credible sources that fall on vulnerable recipients' receptive, dispositional feeling states. These infective stimuli trigger reactive and defensive emotions and associated behaviors reflecting responses to significant threats or benefits relative to the individual's deepest needs, motivations, and values. Defensive overreactions may occur in response to messages to which individuals have been previously sensitized. Infective message contents appear to assimilate into constantly evolving, dynamic autobiographical brain maps consisting of highly specific neuronal networks that range from the brainstem through limbic structures to multiple cortical areas. Autobiographical maps built from message-injected contents may transform, akin to the incorporation of retroviruses or prions, to encode personal identities as aspects of the self. Contrasting maps may exist semi-independently of one another, continuously evolving, interacting, combining, dividing, conflicting, and contending with one another for attention. Achieving attentional awareness, such maps help structure how individuals conceptualize and communicate about their encoded traumas, diverse identities, and the conflicts among them.

CONCLUSIONS AND IMPLICATIONS

During psychotherapy, aftereffects of traumatizing infective messages might be detoxified by deconstructing, desensitizing, and processing messages' precise words and emotional envelopes in relation to contexts in which they were delivered, and the individual's inner dispositions at moments of impact. Carefully crafted, timely interpretations can be therapeutically infective, generating enduring positive impacts. Future studies using an assortment of approaches can test these perspectives.

Visceromotor Roots of Aesthetic Evaluation of Pain in art: an fMRI Study

Empathy for pain involves sensory and visceromotor brain regions relevant also in the first-person pain experience. Focusing on brain activations associated with vicarious experiences of pain triggered by artistic or non-artistic images, the present study aims to investigate common and distinct brain activation patterns associated with these two vicarious experiences of pain and to assess whether empathy for pain brain regions contributes to the formation of an aesthetic judgement (AJ) in non-art expert observers. Artistic and non-artistic facial expressions (painful and neutral) were shown to participants inside the scanner and then aesthetically rated in a subsequent behavioural session. Results showed that empathy for pain brain regions (i.e. bilateral insular cortex, posterior sector of the anterior cingulate cortex and the anterior portion of the middle cingulate cortex) and bilateral inferior frontal gyrus are commonly activated by artistic and non-artistic painful facial expressions. For the artistic representation of pain, the activity recorded in these regions directly correlated with participants’ AJ. Results also showed the distinct activation of a large cluster located in the posterior cingulate cortex/precuneus for non-artistic stimuli. This study suggests that non-beauty-specific mechanisms such as empathy for pain are crucial components of the aesthetic experience of artworks.

The bed nucleus of the stria terminalis and functionally linked neurocircuitry modulate emotion processing and HPA axis dysfunction in posttraumatic stress disorder

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Task-based functional cooccurrence (tbFC) elucidates role of BNST in human PTSD neurocircuitry.

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The BNST is hyperactive during the processing of trauma-related words in PTSD.

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BNST activity correlates to PTSD symptom severity and reduced diurnal cortisol index.

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The BNST has positive tbFC with negative emotion- and stress-related neurocircuitry.

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The BNST has negative tbFC with executive function and stress regulation neurocircuitry.

Background

The bed nucleus of the stria terminalis (BNST) plays an important role in rodent posttraumatic stress disorder (PTSD), but evidence to support its relevance to human PTSD is limited. We sought to understand the role of the BNST in human PTSD via fMRI, behavioral, and physiological measurements.

Methods

29 patients with PTSD (childhood sexual abuse) and 23 healthy controls (HC) underwent BOLD imaging with an emotional word paradigm. Symptom severity was assessed using the Clinician-Administered PTSD Scale and HPA-axis dysfunction was assessed by measuring the diurnal cortisol amplitude index (DCAI). A data-driven multivariate analysis was used to determine BNST task-based functional co-occurrence (tbFC) across individuals.

Results

In the trauma-versus-neutral word contrast, patients showed increased activation compared to HC in the BNST, medial prefrontal cortex (mPFC), posterior cingulate gyrus (PCG), caudate heads, and midbrain, and decreased activation in dorsolateral prefrontal cortex (DLPFC). Symptom severity positively correlated with activity in the BNST, caudate head, amygdala, hippocampus, dorsal anterior cingulate gyrus (dACG), and PCG, and negatively with activity in the medial orbiotofrontal cortex (mOFC) and DLPFC. Patients and HC showed marked differences in the relationship between the DCAI and BOLD activity in the BNST, septal nuclei, dACG, and PCG. Patients showed stronger tbFC between the BNST and closely linked limbic and subcortical regions, and a loss of negative tbFC between the BNST and DLPFC.

Conclusions

Based upon novel data, we present a new model of dysexecutive emotion processing and HPA-axis dysfunction in human PTSD that incorporates the role of the BNST and functionally linked neurocircuitry.

Episodic memory for visual scenes suggests compensatory brain activity in breast cancer patients: a prospective longitudinal fMRI study

It has been hypothesized that breast cancer and its chemotherapy can impart functional neural changes via an overlap with biological mechanisms associated with aging. Here we used fMRI to assess whether changes in neural activity accompanying visual episodic memory encoding and retrieval suggest altered activations according to patterns seen in functional imaging of cognitive aging. In a prospective longitudinal design, breast cancer patients (n = 13) were scanned during memory encoding and retrieval before and after chemotherapy treatment, and compared to healthy-age matched controls (n = 13). Our results indicate that despite equivalent behavioral performance, encoding and retrieval resulted in increased activation of prefrontal regions for the breast cancer group compared to controls for both before and after chemotherapy treatment. This was accompanied by decreased activity in posterior brain regions after chemotherapy, particularly those involved in visual processing, for the breast cancer group compared to controls. These findings are discussed as evidence for a possible anterior shift in neural processing to compensate for deficiencies in posterior brain regions, consistent with an accelerated aging account. Cancer and chemotherapy can impact brain regions underlying episodic memory, leading to additional recruitment of control regions, which may be linked to mechanisms related to aging.

From words to action: Implicit attention to antisocial semantic cues predicts aggression and amygdala reactivity to angry faces in healthy young women

Implicit measures of aggressiveness are able to circumvent response biases that plague self-reports, but it is unclear how they link to neural activation during aggressive interactions and to aggression-related endocrine function. Here, we tested whether an implicit attentional bias toward antisocial semantic information was associated with endogenous testosterone (T) and cortisol (C) levels, as well as with aggressive behavior and amygdala reactivity to angry faces in a separate competitive paradigm. On Day one, participants (39 healthy young women) completed an emotional word Stroop task in which they had to indicate the font color of antisocial, prosocial, or neutral words. On Day two, we measured subjects' brain activity during a competitive reaction time task in which the female opponent displayed angry or neutral facial expressions at the start of each trial and provoked participants with increasingly strong sound blasts. T and C were measured in saliva during a regular weekday as well as before and after scanning. We previously showed that aggression was associated with enhanced amygdala reactivity to angry faces in this sample. The present analyses revealed that subjects were slower to identify the font color of antisocial relative to neutral words, and that this attentional bias predicted higher aggression. T and C were uncorrelated with Stroop scores. Crucially, the relationship between implicit attention to antisocial words and aggression was mediated by amygdala reactivity to angry faces. Our data indicate that a tendency to dwell on implicit hostile cues reflects enhanced responsivity to overt anger displays.

The Language, Tone and Prosody of Emotions: Neural Substrates and Dynamics of Spoken-Word Emotion Perception

Rapid assessment of emotions is important for detecting and prioritizing salient input. Emotions are conveyed in spoken words via verbal and non-verbal channels that are mutually informative and unveil in parallel over time, but the neural dynamics and interactions of these processes are not well understood. In this paper, we review the literature on emotion perception in faces, written words, and voices, as a basis for understanding the functional organization of emotion perception in spoken words. The characteristics of visual and auditory routes to the amygdala—a subcortical center for emotion perception—are compared across these stimulus classes in terms of neural dynamics, hemispheric lateralization, and functionality. Converging results from neuroimaging, electrophysiological, and lesion studies suggest the existence of an afferent route to the amygdala and primary visual cortex for fast and subliminal processing of coarse emotional face cues. We suggest that a fast route to the amygdala may also function for brief non-verbal vocalizations (e.g., laugh, cry), in which emotional category is conveyed effectively by voice tone and intensity. However, emotional prosody which evolves on longer time scales and is conveyed by fine-grained spectral cues appears to be processed via a slower, indirect cortical route. For verbal emotional content, the bulk of current evidence, indicating predominant left lateralization of the amygdala response and timing of emotional effects attributable to speeded lexical access, is more consistent with an indirect cortical route to the amygdala. Top-down linguistic modulation may play an important role for prioritized perception of emotions in words. Understanding the neural dynamics and interactions of emotion and language perception is important for selecting potent stimuli and devising effective training and/or treatment approaches for the alleviation of emotional dysfunction across a range of neuropsychiatric states.