There is more than the amygdala: potential threat assessment in the cingulate cortex

Diminished reward circuit response underlies pain avoidance learning deficits in problem drinkers

Individuals engaging in problem drinking show impaired proactive pain avoidance. As successful pain avoidance is intrinsically rewarding, this impairment suggests reward deficiency, as hypothesized for those with alcohol and substance misuse. Nevertheless, how reward circuit dysfunctions impact avoidance learning and contribute to drinking behavior remains poorly understood. Here, we combined functional imaging and a probabilistic learning go/nogo task to examine the neural processes underlying proactive pain avoidance learning in 103 adult drinkers. We hypothesized that greater drinking severity would be associated with poorer avoidance learning and that the deficits would be accompanied by weakened activity and connectivity of the reward circuit. Our behavioral findings indeed showed a negative relationship between drinking severity and learning from successful pain avoidance. We identified hypoactivation of the posterior cingulate cortex (PCC), a brain region important in avoidance, as the neural correlate of lower learning rate in association with problem drinking. The reward circuit, including the medial orbitofrontal cortex, ventral tegmental area, and substantia nigra, also exhibited diminished activation and connectivity with the PCC with greater drinking severity and learning deficits. Finally, path modeling suggested a pathway in which problem drinking disengaged the reward circuit. The weakened circuit subsequently induced PCC hypoactivation, resulting in poorer pain avoidance learning. As the learning dysfunction worsened alcohol use, the pathway represents a self-perpetuating cycle of drinking and distress. Together, these findings substantiate a role of reward deficiency in problem drinkers' compromised proactive avoidance, thus identifying a potential target for intervention aimed at mitigating harmful alcohol use.

The Organization of Anxiety Symptoms Along the Threat Imminence Continuum

Pathological anxiety is highly prevalent, impairing, and often chronic. Yet, despite considerable research, mechanistic understanding of anxiety and its translation to clinical practice remain limited. Here, we first highlight two foundational complications that contribute to this gap: a reliance on a phenomenology-driven definition of pathological anxiety in neurobiological mechanistic research, and a limited understanding of the chronicity of anxiety symptom expression. We then posit that anxiety symptoms may reflect aberrant expression of otherwise normative defensive responses. Accordingly, we propose that threat imminence, an organizing dimension for normative defensive responses observed across species, may be applied to organize and understand anxiety symptoms along a temporal dimension of expression. Empirical evidence linking distinct anxiety symptoms and the aberrant expression of imminence-dependent defensive responses is reviewed, alongside the neural mechanisms which may underpin these cognitive, physiological, and behavioral responses. Drawing from extensive translational and clinical research, we suggest that understanding anxiety symptoms through this neurobiologically-informed framework may begin to overcome the conceptual complications hindering advancement in mechanistic research and clinical interventions for pathological anxiety.

The risks of unconcern: low sensitivity to threat can have unfortunate consequences

Each one of us is confronted with warnings of danger or threats to wellbeing in our everyday life, whether in the form of certain road signs, Public Service Announcements, ominous changes in bodily functioning, or cautionary tales heard from family or friends. There is great inter-individual variation in how people respond to such threats, with some people habitually tending to ignore or dismiss them, often to their peril. The first purpose of the present paper is to review several studies showing that individuals-most often men-who score very low on measures of trait anxiety are more likely to engage in behaviors that could jeopardize their physical wellbeing. The general hypothesis that is derived from that review is that when attention to everyday threats is chronically muted by way of a dispositional trait, the likelihood of proceeding down some dangerous path is increased. Those findings are then discussed within the broader context of personality theory to highlight the importance of recognizing the bipolarity of common traits. Here the case is made for replacing the term trait anxiety with the term threat sensitivity in order to capture the full breadth of this basic personality variable. A discussion of the neurobiological underpinnings of threat sensitivity is then presented with an emphasis on individual and sex differences in the workings of the defensive survival circuitry. Taken together, this paper has implications for two subfields within psychology. For the area of personality theory, this paper provides support for the adaptationist view with the argument that low threat sensitivity has both adaptive and maladaptive potential. For the area of health psychology, it is argued that some individuals who demonstrate a habitual tendency to neglect their physical wellbeing may be acting-at least in part-in accordance with their innate neurobiological constitution.

The impact of cannabidiol placebo on amygdala-based neural responses to an acute stressor

BACKGROUND

Cannabidiol (CBD) impacts brain regions implicated in anxiety reactivity and stress reactivity (e.g., amygdala, anterior cingulate cortex (ACC), anterior insula (AI)); however, placebo-controlled studies are mixed regarding CBD's anxiolytic effects. We previously reported that CBD expectancy alone can alter subjective, physiological, and endocrine markers of stress/anxiety; however, it is unclear whether these findings reflect altered brain reactivity. This study evaluated whether CBD expectancy independently alters amygdala resting-state functional connectivity (rsFC) with the ACC and AI following acute stress.

METHOD

Thirty-eight (20 females) healthy adults were randomly assigned to receive accurate or inaccurate information regarding the CBD content of a CBD-free oil administered during a single experimental session. Following a baseline resting state MRI scan, participants administered their assigned oil sublingually, engaged in a stress task (serial subtraction with negative feedback) inside the scanner, and underwent another resting state MRI scan. Amygdala rsFC with the ACC and AI was measured during each scan, and the subjective state was assessed at six time points. Outcomes were analyzed using ANCOVA.

RESULTS

CBD expectancy (vs CBD-free expectancy) was associated with significantly weaker rsFC between the left amygdala and right ACC (p = 0.042), but did not systematically alter amygdala-AI rsFC (p-values > 0.05). We also replicated our previously reported CBD expectancy effects on subjective stress/anxiety in the scanner context.

CONCLUSION

CBD placebo effects may be sufficient to alter neural responses relevant to its purported anxiolytic and stress-relieving properties. Future work is needed to replicate these results and determine whether CBD expectancy and pharmacology interact to alter neural anxiety reactivity and stress reactivity.

Convergent functional change of frontoparietal network in obsessive-compulsive disorder: a voxel-based meta-analysis

Background

Obsessive-compulsive disorder (OCD) is a chronic psychiatric illness with complex clinical manifestations. Cognitive dysfunction may underlie OC symptoms. The frontoparietal network (FPN) is a key region involved in cognitive control. However, the findings of impaired FPN regions have been inconsistent. We employed meta-analysis to identify the fMRI-specific abnormalities of the FPN in OCD.

Methods

PubMed, Web of Science, Scopus, and EBSCOhost were searched to screen resting-state functional magnetic resonance imaging (rs-fMRI) studies exploring dysfunction in the FPN of OCD patients using three indicators: the amplitude of low-frequency fluctuation/fractional amplitude of low-frequency fluctuation (ALFF/fALFF), regional homogeneity (ReHo) and functional connectivity (FC). We compared all patients with OCD and control group in a primary analysis, and divided the studies by medication in secondary meta-analyses with the activation likelihood estimation (ALE) algorithm.

Results

A total of 31 eligible studies with 1359 OCD patients (756 men) and 1360 healthy controls (733 men) were included in the primary meta-analysis. We concluded specific changes in brain regions of FPN, mainly in the left dorsolateral prefrontal cortex (DLPFC, BA9), left inferior frontal gyrus (IFG, BA47), left superior temporal gyrus (STG, BA38), right posterior cingulate cortex (PCC, BA29), right inferior parietal lobule (IPL, BA40) and bilateral caudate. Additionally, altered connectivity within- and between-FPN were observed in the bilateral DLPFC, right cingulate gyrus and right thalamus. The secondary analyses showed improved convergence relative to the primary analysis.

Conclusion

OCD patients showed dysfunction FPN, including impaired local important nodal brain regions and hypoconnectivity within the FPN (mainly in the bilateral DLPFC), during the resting state. Moreover, FPN appears to interact with the salience network (SN) and default mode network (DMN) through pivotal brain regions. Consistent with the hypothesis of fronto-striatal circuit dysfunction, especially in the dorsal cognitive circuit, these findings provide strong evidence for integrating two pathophysiological models of OCD.

c-Fos expression after neonatal handling in social brain regions: Distinctive profile of RHA-rat schizophrenia model on a social preference test

Neonatal handling (NH) is an environmental manipulation that induces long-lasting changes in behavioural, neuroendocrine, and neuroanatomical processes in rodents. We have previously reported that NH treatment increases social interaction preference in an animal model of schizophrenia-relevant features, the Roman high-avoidance (RHA) rats. The present study was aimed at evaluating whether the increase of social behaviour/preference due to NH treatment in RHA rats is associated with differences in c-Fos expression levels in some of the brain areas that integrate the "social brain". To this aim, we evaluated the performance of adult male rats from both Roman rat strains (RHA vs. RLA -Roman low-avoidance- rats), either untreated (control) or treated with NH (administered during the first 21 days of life) in a social interaction task. For the analyses of c-Fos activation untreated and NH-treated animals were divided into three different experimental conditions: undisturbed home cage controls (HC); rats exposed to the testing set-up context (CTX); and rats exposed to a social interaction (SI) test. It was found that, compared with their RLA counterparts, NH treatment increased social behaviour in RHA rats, and also specifically enhanced c-Fos expression in RHA rats tested for SI in some brain areas related to social behaviour, i.e. the infralimbic cortex (IL) and the medial posterodorsal amygdala (MePD) regions.

Silence and its effects on the autonomic nervous system: A systematic review

This systematic review explores the influence of silence on the autonomic nervous system. The Polyvagal Theory has been used as a reference model to describe the autonomic nervous system by explaining its role in emotional regulation, social engagement, and adaptive physiological responses. PubMed, Scopus, PsycInfo, EMBASE, and Google Scholar were systematically searched up until July 2023 for relevant studies. The literature search yielded 511 results, and 37 studies were eventually included in this review. Silence affects the autonomic nervous system differently based on whether it is inner or outer silence. Inner silence enhances activity of the ventral vagus, favoring social engagement, and reducing sympathetic nervous system activity and physiological stress. Outer silence, conversely, can induce a heightened state of alertness, potentially triggering vagal brake removal and sympathetic nervous system activation, though with training, it can foster inner silence, preventing such activation. The autonomic nervous system response to silence can also be influenced by other factors such as context, familiarity with silence, presence and quality of outer noise, and empathy.

Understanding anxiety symptoms as aberrant defensive responding along the threat imminence continuum

Threat-anticipatory defensive responses have evolved to promote survival in a dynamic world. While inherently adaptive, aberrant expression of defensive responses to potential threat could manifest as pathological anxiety, which is prevalent, impairing, and associated with adverse outcomes. Extensive translational neuroscience research indicates that normative defensive responses are organized by threat imminence, such that distinct response patterns are observed in each phase of threat encounter and orchestrated by partially conserved neural circuitry. Anxiety symptoms, such as excessive and pervasive worry, physiological arousal, and avoidance behavior, may reflect aberrant expression of otherwise normative defensive responses, and therefore follow the same imminence-based organization. Here, empirical evidence linking aberrant expression of specific, imminence-dependent defensive responding to distinct anxiety symptoms is reviewed, and plausible contributing neural circuitry is highlighted. Drawing from translational and clinical research, the proposed framework informs our understanding of pathological anxiety by grounding anxiety symptoms in conserved psychobiological mechanisms. Potential implications for research and treatment are discussed.

Brain networks under uncertainty: A coordinate-based meta-analysis of brain imaging studies

In recent years, uncertainty has been extensively studied as a core factor in anxiety models. However, it remains unclear whether there is a stable brain circuitry to cope with uncertainty. Addressing this yet open question, we first distinguish uncertainty into three different states: risky, ambiguity, and threat anticipation. Then, we performed three meta-analyses of fMRI studies to identify those regions that are commonly activated by the three domains using activation likelihood estimation (ALE). The overlapping analyses of the three ALE maps revealed major conjunctions of the risk decision making, ambiguity decision making, and the threat anticipation in specifically the right insula. Contrast analysis further confirmed this finding. In addition, different uncertainty states also have different brain networks involved. Specifically, a large number of brain regions in the frontal-parietal cortex were recruited under ambiguity state, while subcortical gray matter regions were recruited under risk decision making, and the bilateral insula were closely associated with threat anticipation. Additionally, we assessed the co-activation pattern of identified regions using meta-analytic connectivity modeling (MACM) to investigate the potential network underlying the relationship of three domains. The MACM analysis further confirmed that different uncertain states have specific brain network basis. We concluded that the right insula serves as a convergent brain region for brain regions recruited for different uncertain states, and its co-activation pattern also corresponds to the brain network of the three uncertain states. This study is a preliminary attempt to further uncover the brain circuitry of anxiety models with uncertainty at their core.

Comparison of Hemodynamic Brain Responses Between Big Wave Surfers and Non-big Wave Surfers During Affective Image Presentation

Background

Big wave surfers are extreme sports athletes who expose themselves to life-threatening risk when training and competing. Little is known about how and why extreme sports athletes choose to participate in their chosen sports. This exploratory study investigated potential neurophysiological and psychometric differences between big and non-big wave surfers.

Methods

Thirteen big wave surfers (BWS) and 10 non-big wave surfers (CON) viewed a series of images from the International Affective Picture System (IAPS) while undergoing brain functional magnetic resonance imaging (fMRI). The Fear Schedule Survey-III, Arnett Inventory of Sensation Seeking, Discrete Emotions Questionnaire, and Positive and Negative Affect Schedule were also completed.

Results

The BWS group demonstrated higher blood-oxygen level-dependent (BOLD) signal change in the insula, visual cortex, and periaqueductal gray, whereas the CON group displayed increased hypothalamus activation in response to high amplitude negative-valence (HAN) image presentation. Psychophysiological interaction (PPI) analyses found CON showed significant interactions between frontal and temporal cortical regions as well as between the hypothalamus and the insula, frontal, and temporal cortices during HAN image presentation that were not seen in BWS. No differences between groups were found in their responses to the questionnaires.

Conclusion

Our findings demonstrate significant differences in brain activation between BWS and CON in response to the presentation of HAN IAPS images, despite no significant differences in scores on psychometric questionnaires.

Altered striatal-opercular intrinsic connectivity reflects decreased aversion to losses in alcohol use disorder

The persistence of addictive behaviours despite their adverse consequences highlights decreased punishment sensitivity as a facet of decision-making impairments in Alcohol Use Disorder (AUD). This attitude departs from the typical loss aversion (LA) pattern, i.e. the stronger sensitivity to negative than positive outcomes, previously associated with striatal and limbic-somatosensory responsiveness in healthy individuals. Consistent evidence highlights decreased LA as a marker of disease severity in AUD, but its neural bases remain largely unexplored. AUD-specific modulations of frontolateral activity by LA were previously related to the higher executive demands of anticipating losses than gains, but the relationship between LA and executive/working-memory performance in AUD is debated. Building on previous evidence of overlapping neural bases of LA during decision-making and at rest, we investigated a possible neural signature of altered LA in AUDs, and its connections with executive skills, in terms of complementary facets of resting-state functioning. In patients, smaller LA than controls, unrelated to executive performance, reflected reduced connectivity within striatal and medial temporal networks, and altered connectivity from these regions to the insular-opercular cortex. AUD-specific loss-related modulations of intrinsic connectivity thus involved structures previously associated both with drug-seeking and with coding the trade-off between appetitive and aversive motivational drives. These findings fit the hypothesis that altered striatal coding of choice-related incentive value, and interoceptive responsiveness to prospective outcomes, enhance neural sensitivity to drug-related stimuli in addictions. LA and its neural bases might prove useful markers of AUD severity and effectiveness of rehabilitation strategies targeting the salience of negative choice outcomes.

Stem Cell Therapy for Post-Traumatic Stress Disorder: A Novel Therapeutic Approach

Stem cell therapy is a rapidly evolving field of regenerative medicine being employed for the management of various central nervous system disorders. The ability to self-renew, differentiate into specialized cells, and integrate into neuronal networks has positioned stem cells as an ideal mechanism for the treatment of epilepsy. Epilepsy is characterized by repetitive seizures caused by imbalance in the GABA and glutamate neurotransmission following neuronal damage. Stem cells provide benefit by reducing the glutamate excitotoxicity and strengthening the GABAergic inter-neuron connections. Similar to the abnormal neuroanatomic location in epilepsy, post-traumatic stress disorder (PTSD) is caused by hyperarousal in the amygdala and decreased activity of the hippocampus and medial prefrontal cortex. Thus, stem cells could be used to modulate neuronal interconnectivity. In this review, we provide a rationale for the use of stem cell therapy in the treatment of PTSD.

Emergency percutaneous coronary intervention and stent implantation: Patients' lived experiences

INTRODUCTION

Given that emergency procedures must be performed immediately and without the possibility of sufficiently informing and preparing a patient, the lived experiences of patients who undergo emergency procedures and those who undergo elective procedures may well differ. Elucidating the lived experiences of patients who underwent percutaneous coronary intervention (PCI) with stent implantation in an emergency situation is crucial because such knowledge might prove helpful in tailoring post-procedure interventions intended to improve the lives of PCI patients.

AIM

To describe the experiences of patients 1 month after they underwent emergency PCI with coronary stent implantation.

METHODS

Cohen's phenomenology was applied in this study. This method combines the characteristics of descriptive (Husserlian) phenomenology with those of interpretative (Gadmerian) phenomenology, and it is by nature an inductive approach. The participants were enrolled 1 month after undergoing PCI with coronary stent implantation. They were interviewed using open-ended questions to provide them full freedom of expression. They were asked to describe their experiences of the PCI and stent implementation they have gone through. This study followed the recommendations of the Standard for Reporting Qualitative Research.

RESULTS

Our sample consisted of 15 participants. Data analysis revealed three main themes: (1) catheter lab and pain, (2) anxiety and feeling uncertain about the future, and (3) lifestyle changes. The anxiety theme encompassed two subthemes: (a) anxiety related to the procedure and (b) anxiety related to the continuation of life.

CONCLUSION

Our study is one of the first works to explicitly investigate the lived experiences of patients who underwent emergency PCI. Understanding the experiences of these patients is key in understanding their realistic needs and concerns.

RELEVANCE TO CLINICAL PRACTICE

Knowledge of the lived experiences of patients who underwent emergency PCI with coronary stent implantation is fundamental in identifying aspects that warrant tailored interventions.

Interaction of Temporal Lobe Epilepsy and Posttraumatic Stress Disorder: Network Analysis of a Single Case

In this case study, we present a 21 years old female with long-standing Temporal Lobe Epilepsy (TLE) who, following a sexual assault, also developed Posttraumatic Stress Disorder (PTSD), leading to a change in her seizure semiology. The new seizures seemed to be a re-enactment of the sexual assault and accordingly were at first thought to be Psychogenic Non-Epileptic Seizures (PNES). Nevertheless, electroencephalography (EEG) recording at the Epilepsy Monitoring Unit (EMU) revealed ictal epileptic brain activity during these new attacks. In order to further explore the nature of the relation between epileptic seizures and PTSD symptomatology, a functional MRI (fMRI) scan was conducted focusing on neural response to threat (fearful faces). The results indicated that the response to threat elicited bilateral amygdala activation, as well as enhanced amygdala connectivity with the insula and anterior cingulate cortex (ACC), all central nodes of the fear circuitry. Accordingly, we suggest that this unique presentation of "pseudo" PNES might stem from the anatomical proximity of the epileptic network in this patient (temporal-insular-frontal) to the fear circuitry, allowing abnormal epileptic activity to "exploit" or activate the fear circuit or vice versa. We further propose that the traumatic experience may have changed the patient's ictal semiology by modifying the course of the spread of the ictal activity toward the PTSD network.

Abnormal dynamic functional connectivity density in patients with generalized anxiety disorder

BACKGROUND

Numerous studies have revealed the abnormal static functional connectivity (FC) among different brain regions in patients with generalized anxiety disorder (GAD). However, little is known about the dynamic changes of FC in patients with GAD.

METHODS

This study investigated the whole-brain dynamic changes of FC in patients with GAD by combining global FC density (FCD) and sliding window correlation analyses. The standard deviation of dynamic FCD (dFCD) was calculated to evaluate its temporal variability along time. Support vector regression was then employed to predict the symptom severity of patients based on abnormal dynamic connectivity patterns.

RESULTS

The abnormal dFCD variability between 81 GAD patients and 80 healthy controls showed that the patients had higher dFCD variability in the bilateral dorsomedial prefrontal cortex (dmPFC) and left hippocampus while lower dFCD variability in the right postcentral gyrus. The abnormal dFCD variability of the left dmPFC is an important feature for anxiety prediction.

LIMITATIONS

The selection of sliding window length remains controversial, and most of our patients have been treated with medications. Future studies are expected to rule out the potential confounding effects from applying different parameters of the sliding window and recruiting large samples of medication-free patients.

CONCLUSION

The altered patterns of time-varying brain connectivity in the frontolimbic and sensorimotor areas may reflect abnormal dynamic neural communication between these regions and other regions of the brain, which may deepen our understanding of the disease.

Structural and functional neural correlates of vigilant and avoidant regulation style

BACKGROUND

Regulation of emotional arousal is a relevant factor for mental health. The investigation of neural underpinnings of regulation styles in healthy individuals may provide important insights regarding potential risk factors. To fill the gap of structural correlates of regulation styles and to expand previous results, we focused on the association between brain structure, neural responsiveness and vigilant/avoidant regulation style.

METHODS

In n = 302 healthy individuals regulation style was assessed with the Mainz Coping Inventory (MCI). Participants underwent structural and functional MRI during an emotion-processing paradigm. Structural MRI (voxel-based morphometry) and functional MRI were analysed in two regions of interest (amygdala and anterior cingulate cortex [ACC]).

RESULTS

Regulation styles did not show an association with brain structure after correction for gender, age, trait anxiety, depressive symptoms. During emotion processing, a vigilant regulation style was negatively associated with ACC activation.

LIMITATIONS

The cross-sectional study in a non-pathological sample is not adequate to unveil causalities or draw conclusions regarding prevention interventions.

CONCLUSION

Regulation styles are associated with specific neural activation patterns. The association of a high-vigilant regulation style and low ACC activation during emotion processing in healthy participants might be a potential risk factor.

Language as a Threat: Multimodal Evaluation and Interventions for Overwhelming Linguistic Anxiety in Severe Aphasia

Linguistic anxiety (LA) is an abnormal stress response induced by situations that require the use of verbal behavior, and it is accentuated during language testing in persons with aphasia (PWA). The presence of LA in PWA may jeopardize the interpretation of cognitive evaluations, leading to biased conclusions about the severity of the language alteration and the effectiveness of the treatments. In the present study, we report the case of a woman (Mrs. A) with severe chronic mixed transcortical aphasia due to left frontal and parietal hemorrhages that partially spared the perisylvian area. Mrs. A was treated with the dopamine agonist Rotigotine alone and combined with Intensive Language-Action Therapy (ILAT). Complementary evaluations included autonomic reactivity during the performance of different language tasks, resting state functional magnetic resonance imaging (rs-fMRI) and [18F]-fluorodeoxyglucose positron emission tomography (18F-FDG-PET). We found that formal language testing in a clinical setting triggered a dramatic increase of automatic echolalia, perseverations and frustration, making the task completion difficult. The treatment improved aphasia, but gains were more robust when evaluation was performed by Mrs. A's husband at home than by clinicians. Autonomic evaluation under Rotigotine revealed higher reactivity during tasks tapping an impaired function in comparison with a task evaluating a preserved function (verbal repetition). Baseline 18F-FDG-PET analysis showed decreased metabolic activity in left limbic-paralimbic areas, whereas rs-fMRI revealed compensatory activity in the right hemisphere. We also analyzed the different factors (e.g., premorbid personality traits, task difficulty) that may have contributed to LA in Mrs. A during language testing. Our findings emphasize the usefulness of implicating adequately trained laypersons in the evaluation and treatment of PWA showing LA. Further studies using multidimensional evaluations are needed to disentangle the interplay between anxiety and abnormal language as well as the neural mechanisms underpinning LA in PWA.

Translational studies support a role for serotonin 2B receptor (HTR2B) gene in aggression-related cannabis response

Cannabis use is increasing in the United States, as are its adverse effects. We investigated the genetics of an adverse consequence of cannabis use: cannabis-related aggression (CRA) using a genome-wide association study (GWAS) design. Our GWAS sample included 3269 African Americans (AAs) and 2546 European Americans (EAs). An additional 89 AA subjects from the Grady Trauma Project (GTP) were also examined using a proxy-phenotype replication approach. We identified genome-wide significant risk loci contributing to CRA in AAs at the serotonin receptor 2B receptor gene (HTR2B), and the lead SNP, HTR2B*rs17440378, showed nominal association to aggression in the GTP cohort of cannabis-exposed subjects. A priori evidence linked HTR2B to impulsivity/aggression but not to cannabis response. Human functional data regarding the HTR2B variant further supported our finding. Treating an Htr2b-/- knockout mouse with THC resulted in increased aggressive behavior, whereas wild-type mice following THC administration showed decreased aggression in the resident-intruder paradigm, demonstrating that HTR2B variation moderates the effects of cannabis on aggression. These concordant findings in mice and humans implicate HTR2B as a major locus associated with cannabis-induced aggression.

Neural correlates of risk perception as a function of risk level: An approach to the study of risk through a daily life task

We are often required to make decisions that can have safe or risky consequences. Evaluating the risk of each possible alternative is an important step before making our final decision. The main goal of the present research was to explore the neural basis of risk perception in a naturalistic context (driving). Twenty-two drivers evaluated the perceived risk in 72 traffic situations (previously categorized by driving instructors) while brain activity was recorded using fMRI. A neural network involving attentional factors, emotional processing, stimulus-response associations, and risk aversion was related to the perception of risks. Given the nature of our task, a more prominent role was played by emotional factors (evaluation of the consequences) than cognitive factors (e.g. probabilistic calculations). Moreover, activation in the insula, inferior frontal gyrus, precentral/postcentral gyrus, inferior parietal gyrus, and temporal and occipital regions linearly increased as a function of risk level. Our findings provide a new step towards understanding the neural processing underlying risk behavior in daily life tasks, which is particularly relevant given the study context and its important practical implications for our society.

Brain responses to stimuli mimicking dental treatment among non-phobic individuals: A meta-analysis

Numerous neuroimaging studies have attempted to identify how the brain responds to stimuli mimicking dental treatment in normal non-phobic individuals. However, results were sometimes inconsistent due to small sample sizes and methodological variations. This meta-analysis employs standardized procedures to summarize data from previous studies to identify brain regions that were consistently activated across studies, elicited by stimuli such as pictures, sounds, or audiovisual footage mimicking those encountered during dental treatments. A systematic literature search was carried out using PubMed and Scopus. The meta-analysis analyzed data from 120 healthy subjects from seven neuroimaging studies. We assessed the risk of bias among the included studies with the Risk of Bias Assessment Tool for Nonrandomized Studies. One study appeared to have a high risk of selection bias, whereas the others were considered to have a low risk of bias. Results revealed three clusters of activation with cluster sizes ranging from 768 mm³ to 1,424 mm³ . Stimuli mimicking dental treatment consistently activated the bilateral anterior insula; right dorsal anterior cingulate, putamen, and medial prefrontal cortex; and left claustrum. This study confirmed that audio and/or visual stimuli mimicking dental treatment consistently activated the fear-related brain regions among healthy subjects, mostly consistent with activations from general anxiety but without the involvement of the amygdala.

Increased Default Mode Network Connectivity in Obsessive-Compulsive Disorder During Reward Processing

Objective: Obsessive-compulsive disorder (OCD) is characterized by anxiety-provoking, obsessive thoughts (i.e., obsessions) which patients react to with compulsive behaviors (i.e., compulsions). Due to the transient feeling of relief following the reduction of obsession-induced anxiety, compulsions are often described as relieving or even rewarding. Several studies investigated functional activation during reward processing in OCD, but findings are heterogeneous up to now and little is known about potential alterations in functional connectivity. Method: Against this background we studied OCD patients (n = 44) and healthy controls (n = 37) during the receipt of monetary reward by assessing both activation and functional connectivity. Results: Patients showed a decreased activation in several frontal regions and the posterior cingulate (PCC, BA31) together with a stronger connectivity between the PCC and the vmPFC (BA10). Conclusion: Present findings demonstrate an increased connectivity in patients within major nodes of the default mode network (DMN)-a network known to be involved in the evaluation of internal mental states. These results may indicate an increased activity of internal, self-related processing at the expense of a normal responsiveness toward external rewards and incentives. This, in turn, may explain the constant urge for additional reinforcement and patients' inability to inhibit their compulsive behaviors.

Frontal and subcortical grey matter reductions in PTSD

Post-traumatic stress disorder (PTSD) is characterised by a range of debilitating psychological, physical and cognitive symptoms. PTSD has been associated with grey matter atrophy in limbic and frontal cortical brain regions. However, previous studies have reported heterogeneous findings, with grey matter changes observed beyond limbic/frontal areas. Seventy-five adults were recruited from the community, 25 diagnosed with PTSD along with 25 healthy and 25 trauma exposed age and gender matched controls. Participants underwent clinical assessment and magnetic resonance imaging. The data-analyses method Voxel Based Morphometry (VBM) was used to estimate cortical grey matter volumes. When compared to both healthy and trauma exposed controls, PTSD subjects demonstrated decreased grey matter volumes within subcortical brain regions-including the hippocampus and amygdala-along with reductions in the anterior cingulate cortex, frontal medial cortex, middle frontal gyrus, superior frontal gyrus, paracingulate gyrus, and precuneus cortex. Significant negative correlations were found between total CAPS lifetime clinical scores/sub-scores and GM volume of both the PTSD and TC groups. GM volumes of the left rACC and right amygdala showed a significant negative correlation within PTSD diagnosed subjects.

Empathizers and systemizers process social information differently

Using the empathizing-systemizing theory as our framework, we investigated how people with high self-reported empathizing (having good social skills and being interested in people) and systemizing (being interested in physical things and processes) differ in the social information processing of emotionally negative photographs of people during "spontaneous watching" and emotional and cognitive empathy tasks. Empathizers evaluated the pictures as more emotionally touching and the reactions in the photographs more understandable than the systemizers. Compared to the empathizers, systemizers had stronger activations in the posterior cingulate cortex, an area related to cognitive empathy, as well as in the left superior temporal gyrus and middle frontal gyrus when watching emotional photographs spontaneously. During guided emotional and cognitive empathy tasks, these differences disappeared. However, during the emotional empathy task, higher systemizing was associated with weaker activation of the right inferior frontal gyrus /insula. Furthermore, during emotional and cognitive empathy tasks, empathizing was related to increased activations of the amygdala which were in turn related to higher behavioral ratings of emotional and cognitive empathy. The results suggest that empathizers and systemizers engage in social information processing differently: systemizers in more cognitive terms and empathizers with stronger automatic emotional reactions.

Neural correlates of the mother-to-infant social transmission of fear

Although clinical and basic studies show that parental trauma, fear, and anxiety may be transmitted to offspring, the neurobiology of this transmission is still not well understood. We recently demonstrated in an animal model that infant rats acquire threat responses to a distinct cue when a mother expresses fear to this cue in their presence. This ability to acquire maternal fear through social learning is present at birth and, as we previously reported, depends on the pup's amygdala. However, the remaining neural mechanisms underlying social fear learning (SFL) in infancy remain elusive. Here, by using [(14) C]2-deoxyglucose autoradiography, we show that the mother-to-infant transmission of fear in preweaning rats is associated with a significant increase of activity in the subregions of the lateral septum, nucleus accumbens, bed nucleus of stria terminalis, retrosplenial cortex, paraventricular nucleus of the thalamus, mediodorsal and intralaminar thalamic nuclei, medial and the lateral preoptic nuclei of the hypothalamus, and the lateral periaqueductal gray. In contrast to studies of adult SFL demonstrating the role of the anterior cingulate cortex and possibly the insular cortex or research of infant classical fear conditioning showing the role of the posterior piriform cortex, no changes of activation in these areas were observed. Our results indicate that the pup's exposure to maternal fear activates a number of areas involved in processing threat, stress, or pain. This pattern of activation suggests a unique set of neural mechanisms underlying SFL in the developing brain.

Anxiety Patients Show Reduced Working Memory Related dlPFC Activation During Safety and Threat

BACKGROUND

Anxiety patients exhibit deficits in cognitive tasks that require prefrontal control of attention, including those that tap working memory (WM). However, it is unclear whether these deficits reflect threat-related processes or symptoms of the disorder. Here, we distinguish between these hypotheses by determining the effect of shock threat versus safety on the neural substrates of WM performance in anxiety patients and healthy controls.

METHODS

Patients, diagnosed with generalized and/or social anxiety disorder, and controls performed blocks of an N-back WM task during periods of safety and threat of shock. We recorded blood-oxygen-level dependent (BOLD) activity during the task, and investigated the effect of clinical anxiety (patients vs. controls) and threat on WM load-related BOLD activation.

RESULTS

Behaviorally, patients showed an overall impairment in both accuracy and reaction time compared to controls, independent of threat. At the neural level, patients showed less WM load-related activation in the dorsolateral prefrontal cortex, a region critical for cognitive control. In addition, patients showed less WM load-related deactivation in the ventromedial prefrontal cortex and posterior cingulate cortex, which are regions of the default mode network. Most importantly, these effects were not modulated by threat.

CONCLUSIONS

This work suggests that the cognitive deficits seen in anxiety patients may represent a key component of clinical anxiety, rather than a consequence of threat.

Functional and structural connectivity of the amygdala in obsessive-compulsive disorder

Background

The amygdala is known to be involved in anxiety processing, but its role in the psychopathology of obsessive-compulsive disorder (OCD) is still unclear.

Aims

In this MRI study we investigated potential alterations in structural and functional connectivity of the amygdala in 42 adult patients with OCD and 37 healthy subjects.

Method

Psychophysiological interaction analysis was used to explore amygdala functional connectivity during a negative affective task. Probabilistic tractography was then employed to study structural connectivity and integrity of underlying white matter fiber tracts.

Results

Compared to controls, OCD patients showed a significantly increased functional connectivity of the left amygdala with mostly parieto-occipital regions during task. No structural connectivity differences could be found between the groups. In addition, only patients showed a significant association between functional and structural connectivity of these regions. Moreover, symptom severity was negatively associated with structural integrity of the underlying white matter tracts.

Conclusions

Present results emphasize the relevance of the amygdala for OCD and may reflect that neuronal alterations in structural connectivity could be associated with functional connectivity alterations in broader networks.

Functional changes in brain activity after hypnosis in patients with dental phobia

Visiting the dentist is often accompanied by apprehension or anxiety. People, who suffer from specific dental phobia (a disproportional fear of dental) procedures show psychological and physiological symptoms which make dental treatments difficult or impossible. For such purposes, hypnosis is often used in dental practice as an alternative for a number of treatments adjuvant or instead of sedation or general anaesthetics, as medication is often associated with risks and side effects. This is the first study to address the effects of a brief dental hypnosis on the fear processing structures of the brain in dental phobics using functional magnetic resonance imaging (fMRI). 12 dental phobics (DP; mean 34.9years) and 12 healthy controls (CO; mean 33.2years) were scanned with a 3T MRI whole body-scanner observing brain activity changes after a brief hypnotic invervention. An fMRI event-related design symptom provocation task applying animated audio-visual pseudorandomized strong phobic stimuli was presented in order to maximize the fearful reactions during scanning. Control videos showed the use of familiar electronic household equipment. In DP group, main effects of fear condition were found in the left amygdala and bilaterally in the anterior cingulate cortex (ACC), insula and hippocampu (R<L). During hypnosis DP showed a significantly reduced activation in all of these areas. Reduced neural activity patterns were also found in the control group. No amygdala activation was detected in healthy subjects in the two experimental conditions. Compared to DP, CO showed less bilateral activation in the insula and ACC in the awake condition. Findings show that anxiety-provoking stimuli such as undergoing dental surgery, endodontic treatments or insufficient anaesthetics, can be effectively reduced under hypnosis. The present study gives scientific evidence that hypnosis is a powerful and successful method for inhibiting the reaction of the fear circuitry structures.

Dominance status predicts social fear transmission in laboratory rats

Acquiring information about stimuli that predict danger, through either direct experience or inference from a social context, is crucial for individuals’ ability to generate appropriate behaviors in response to threats. Utilizing a modified demonstrator–observer paradigm (fear conditioning by proxy) that allows for free interaction between subjects, we show that social dominance hierarchy, and the interactive social behaviors of caged rats, is predictive of social fear transmission, with subordinate rats displaying increased fear responses after interacting with a fear-conditioned dominant rat during fear retrieval. Fear conditioning by proxy conserves some of the pathways necessary for direct fear learning (e.g., lateral amygdala) but is unique in that it requires regions necessary for emotional regulation (e.g., anterior cingulate cortex), making this paradigm an important tool for evaluating learning and behavior in the laboratory setting.

Role of the dorsal anterior cingulate cortex in obsessive-compulsive disorder: converging evidence from cognitive neuroscience and psychiatric neurosurgery

OBJECTIVE Advances in understanding the neurobiological basis of psychiatric disorders will improve the ability to refine neuromodulatory procedures for treatment-refractory patients. One of the core dysfunctions in obsessive-compulsive disorder (OCD) is a deficit in cognitive control, especially involving the dorsal anterior cingulate cortex (dACC). The authors' aim was to derive a neurobiological understanding of the successful treatment of refractory OCD with psychiatric neurosurgical procedures targeting the dACC. METHODS First, the authors systematically conducted a review of the literature on the role of the dACC in OCD by using the search terms "obsessive compulsive disorder" and "anterior cingulate." The neuroscience literature on cognitive control mechanisms in the dACC was then combined with the literature on psychiatric neurosurgical procedures targeting the dACC for the treatment of refractory OCD. RESULTS The authors reviewed 89 studies covering topics that included structural and functional neuroimaging and electrophysiology. The majority of resting-state functional neuroimaging studies demonstrated dACC hyperactivity in patients with OCD relative to that in controls, while task-based studies were more variable. Electrophysiological studies showed altered dACC-related biomarkers of cognitive control, such as error-related negativity in OCD patients. These studies were combined with the cognitive control neurophysiology literature, including the recently elaborated expected value of control theory of dACC function. The authors suggest that a central feature of OCD pathophysiology involves the generation of mis-specified cognitive control signals by the dACC, and they elaborate on this theory and provide suggestions for further study. CONCLUSIONS Although abnormalities in brain structure and function in OCD are distributed across a wide network, the dACC plays a central role. The authors propose a theory of cognitive control dysfunction in OCD that attempts to explain the therapeutic efficacy of dACC neuromodulation. This theoretical framework should help to guide further research into targeted treatments of OCD and other disorders of cognitive control.

Criticism hurts everybody, praise only some: Common and specific neural responses to approving and disapproving social-evaluative videos

Social evaluation is a ubiquitous feature of daily interpersonal interactions and can produce strong positive or negative emotional reactions. While previous research has highlighted neural correlates of static or dynamic facial expressions, little is known about neural processing of more naturalistic social interaction simulations or the modulating role of inter-individual differences such as trait fear of negative/positive evaluation. The present fMRI study investigated neural activity of 37 (21 female) healthy participants while watching videos of posers expressing a range of positive, negative, and neutral statements tapping into several basic and social emotions. Unpleasantness ratings linearly increased in response to positive to neutral to negative videos whereas arousal ratings were elevated in both emotional video conditions. At the whole brain level, medial prefrontal and rostral anterior cingulate cortex activated strongly in both emotional conditions which may be attributed to the cognitive processing demands of responding to complex social evaluation. Region of interest analysis for basic emotion processing areas revealed enhanced amygdala activation in both emotional conditions, whereas anterior and posterior insula showed stronger activity during negative evaluations only. Individuals with high fear of positive evaluation were characterized by increased posterior insula activity during positive videos, suggesting heightened interoception. Taken together, these results replicate and extend studies that used facial expression stimuli and reveal neurobiological systems involved in processing of more complex social-evaluative videos. Results also point to vulnerability factors for social-interaction related psychopathologies.

Effects of dopamine D1 modulation of the anterior cingulate cortex in a fear conditioning procedure

The anterior cingulate cortex (AC) component of the medial prefrontal cortex (mPFC) has been implicated in attention and working memory as measured by trace conditioning. Since dopamine (DA) is a key modulator of mPFC function, the present study evaluated the role of DA receptor agents in rat AC, using trace fear conditioning. A conditioned stimulus (CS, noise) was followed by an unconditioned stimulus (US, shock) with or without a 10s trace interval interposed between these events in a between-subjects design. Conditioned suppression of drinking was assessed in response to presentation of the CS or an experimental background stimulus (flashing lights, previously presented for the duration of the conditioning session). The selective D1 agonist SKF81297 (0.05μg/side) or D1 antagonist SCH23390 (0.5μg/side) was administered by intra-cerebral microinfusion directly into AC. It was predicted that either of these manipulations should be sufficient to impair trace (but not delay) conditioning. Counter to expectation, there was no effect of DA D1 modulation on trace conditioning as measured by suppression to the noise CS. However, rats infused with SKF81297 acquired stronger conditioned suppression to the experimental background stimulus than those infused with SCH23390 or saline. Thus, the DA D1 agonist SKF81297 increased conditioned suppression to the contextual background light stimulus but was otherwise without effect on fear conditioning.

Variants of contextual fear conditioning induce differential patterns of Egr-1 activity within the young adult prefrontal cortex

Contextual fear conditioning is a form of associative learning where animals must experience a context before they can associate it with an aversive stimulus. Single-trial contextual fear conditioning (sCFC) and the context preexposure facilitation effect (CPFE) are two variants of CFC where learning about the context is temporally contiguous (sCFC) with or separated (CPFE) from receiving a footshock in that context. Neural activity within CA1 of the dorsal hippocampus (CA1), amygdala (LA), and prefrontal cortex (PFC) may play a critical role when animals learn to associate a context with a footshock (i.e., training). Previous studies from our lab have found that early-growth-response gene 1 (Egr-1), an immediate early gene, exhibits unique patterns of activity within regions of the PFC following training in sCFC and the CPFE of juvenile rats. In the present study, we extended our studies by examining Egr-1 expression in young adult rats to determine (1) if our previous work reflected changes unique to development or extend into adulthood and (2) to contrast expression profiles between sCFC and the CPFE. Rats that learned context fear with sCFC showed increased Egr-1 in the anterior cingulate, orbitofrontal and infralimbic cortices relative to non-associative controls following training, but expression in prelimbic cortex did not differ between fear conditioned and non-associative controls. In contrast, rats trained in the CPFE also showed increased Egr-1 in all the prefrontal cortex regions, including prelimbic cortex. These findings replicate our previous findings in juveniles and suggest that Egr-1 in specific PFC subregions may be uniquely involved in learning context-fear in the CPFE compared to sCFC.

Functional organization of human subgenual cortical areas: Relationship between architectonical segregation and connectional heterogeneity

Human subgenual anterior cingulate cortex (sACC) is involved in affective experiences and fear processing. Functional neuroimaging studies view it as a homogeneous cortical entity. However, sACC comprises several distinct cyto- and receptorarchitectonical areas: 25, s24, s32, and the ventral portion of area 33. Thus, we hypothesized that the areas may also be connectionally and functionally distinct. We performed structural post mortem and functional in vivo analyses. We computed probabilistic maps of each area based on cytoarchitectonical analysis of ten post mortem brains. Maps, publicly available via the JuBrain atlas and the Anatomy Toolbox, were used to define seed regions of task-dependent functional connectivity profiles and quantitative functional decoding. sACC areas presented distinct co-activation patterns within widespread networks encompassing cortical and subcortical regions. They shared common functional domains related to emotion, perception and cognition. A more specific analysis of these domains revealed an association of s24 with sadness, and of s32 with fear processing. Both areas were activated during taste evaluation, and co-activated with the amygdala, a key node of the affective network. s32 co-activated with areas of the executive control network, and was associated with tasks probing cognition in which stimuli did not have an emotional component. Area 33 was activated by painful stimuli, and co-activated with areas of the sensorimotor network. These results support the concept of a connectional and functional specificity of the cyto- and receptorarchitectonically defined areas within the sACC, which can no longer be seen as a structurally and functionally homogeneous brain region.

Cardiac and electro-cortical concomitants of social feedback processing in women

This study provides a joint analysis of the cardiac and electro-cortical-early and late P3 and feedback-related negativity (FRN)-responses to social acceptance and rejection feedback. Twenty-five female participants performed on a social- and age-judgment control task, in which they received feedback with respect to their liking and age judgments, respectively. Consistent with previous reports, results revealed transient cardiac slowing to be selectively prolonged to unexpected social rejection feedback. Late P3 amplitude was more pronounced to unexpected relative to expected feedback. Both early and late P3 amplitudes were shown to be context dependent, in that they were more pronounced to social as compared with non-social feedback. FRN amplitudes were more pronounced to unexpected relative to expected feedback, irrespective of context and feedback valence. This pattern of findings indicates that social acceptance and rejection feedback have widespread effects on bodily state and brain function, which are modulated by prior expectancies.

Imbalance in habitual versus goal directed neural systems during symptom provocation in obsessive-compulsive disorder

Intrusive thoughts and compulsive urges to perform stereotyped behaviours are typical symptoms of obsessive-compulsive disorder. Emerging evidence suggests a cognitive bias towards habit formation at the expense of goal-directed performance in obsessive-compulsive disorder. In this study, we test this hypothesis using a novel individualized ecologically valid symptom provocation design: a live provocation functional magnetic resonance imaging paradigm with synchronous video-recording of behavioural avoidance responses. By pairing symptom provocation with online avoidance responses on a trial-by-trial basis, we sought to investigate the neural mechanisms leading to the compulsive avoidance response. In keeping with the model of habit formation in obsessive-compulsive disorder, we hypothesized that this disorder would be associated with lower activity in regions implicated in goal-directed behaviours and higher activity in regions implicated in habitual behaviours. Fifteen patients with obsessive-compulsive disorder and 15 healthy control volunteers participated in this functional magnetic resonance imaging study. Online stimuli were individually tailored to achieve effective symptom provocation at neutral, intermediate and strong intensity levels. During the symptom provocation block, the participant could choose to reject or terminate the provoking stimuli resulting in cessation of the symptom provocation. We thus separately analysed the neural correlates of symptom provocation, the urge to avoid, rejection and relief. Strongly symptom-provoking conditions evoked a dichotomous pattern of deactivation/activation in patients, which was not observed either in control conditions or in healthy subjects: a deactivation of caudate-prefrontal circuits accompanied by hyperactivation of subthalamic nucleus/putaminal regions. This finding suggests a dissociation between regions engaged in goal-directed and habitual behaviours. The putaminal hyperactivity during patients' symptom provocation preceded subsequent deactivation during avoidance and relief events, indicating a pivotal role of putamen in regulation of behaviour and habit formation in obsessive-compulsive disorder. Effective connectivity analysis identified the ventromedial prefrontal cortex/orbitofrontal cortex as the main structure in this circuitry involved in the modulation of compulsivity in obsessive-compulsive disorder. These findings suggest an imbalance in circuitry underlying habitual and goal-directed action control, which may represent a fundamental mechanism underlying compulsivity in obsessive-compulsive disorder. Our results complement current models of symptom generation in obsessive-compulsive disorder and may enable the development of future therapeutic approaches that aim to alleviate this imbalance.

Obsessive-compulsive disorder

This article reviews the clinical features and neurochemical hypotheses of obsessive-compulsive disorder (OCD) with a focus on the serotonin system. In DSM-5, OCD was moved from the anxiety disorders to a new category of Obsessive-Compulsive and Related Disorders. OCD is a common, typically persistent disorder marked by intrusive and disturbing thoughts (obsessions) and repetitive behaviors (compulsions) that the person feels driven to perform. The preferential efficacy of serotonin reuptake inhibitors (SRIs) in OCD led to the so-called serotonin hypothesis. However, direct support for a role of serotonin in the pathophysiology (e.g., biomarkers in pharmacological challenge studies) of OCD remains elusive. A role of the glutamatergic system in OCD has been gaining traction based on imaging data, genomic studies and animal models of aberrant grooming behavior. These findings have spurred interest in testing the efficacy of medications that modulate glutamate function. A role of glutamate is compatible with circuit-based theories of OCD.

Equal pain-Unequal fear response: enhanced susceptibility of tooth pain to fear conditioning

Experimental fear conditioning in humans is widely used as a model to investigate the neural basis of fear learning and to unravel the pathogenesis of anxiety disorders. It has been observed that fear conditioning depends on stimulus salience and subject vulnerability to fear. It is further known that the prevalence of dental-related fear and phobia is exceedingly high in the population. Dental phobia is unique as no other body part is associated with a specific phobia. Therefore, we hypothesized that painful dental stimuli exhibit an enhanced susceptibility to fear conditioning when comparing to equal perceived stimuli applied to other body sites. Differential susceptibility to pain-related fear was investigated by analyzing responses to an unconditioned stimulus (UCS) applied to the right maxillary canine (UCS-c) vs. the right tibia (UCS-t). For fear conditioning, UCS-c and USC-t consisted of painful electric stimuli, carefully matched at both application sites for equal intensity and quality perception. UCSs were paired to simple geometrical forms which served as conditioned stimuli (CS+). Unpaired CS+ were presented for eliciting and analyzing conditioned fear responses. Outcome parameter were (1) skin conductance changes and (2) time-dependent brain activity (BOLD responses) in fear-related brain regions such as the amygdala, anterior cingulate cortex, insula, thalamus, orbitofrontal cortex, and medial prefrontal cortex. A preferential susceptibility of dental pain to fear conditioning was observed, reflected by heightened skin conductance responses and enhanced time-dependent brain activity (BOLD responses) in the fear network. For the first time, this study demonstrates fear-related neurobiological mechanisms that point toward a superior conditionability of tooth pain. Beside traumatic dental experiences our results offer novel evidence that might explain the high prevalence of dental-related fears in the population.

Insula and anterior cingulate GABA levels in posttraumatic stress disorder: preliminary findings using magnetic resonance spectroscopy

BACKGROUND

Increased reactivity of the insular cortex and decreased activity of the dorsal anterior cingulate cortex (ACC) are seen in functional imaging studies of posttraumatic stress disorder (PTSD), and may partly explain the persistent fear and anxiety proneness that characterize the disorder. A possible neurochemical correlate is altered function of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). We report results from what we believe is the first study applying proton magnetic resonance spectroscopy ((1) H-MRS) to measure brain GABA in PTSD.

METHODS

Thirteen adults with DSM-IV PTSD and 13 matched healthy control subjects underwent single voxel (1) H-MRS at 4 Tesla. GABA was measured in the right anterior insula and dorsal ACC, using Mescher-Garwood Point-Resolved Echo Spectroscopy Sequence (MEGAPRESS) spectral editing. Subjects were interviewed with the Structured Clinical Interview for DSM-IV and the Clinician Administered PTSD Scale, and also completed the State and Trait Anxiety Inventory.

RESULTS

Insula GABA was significantly lower in PTSD subjects than in controls, and dorsal ACC GABA did not differ significantly between the groups. Insula GABA was not significantly associated with severity of PTSD symptoms. However, lower insula GABA was associated with significantly higher state and trait anxiety in the subject sample as a whole.

CONCLUSIONS

PTSD is associated with reduced GABA in the right anterior insula. This preliminary evidence of the (1) H-MRS GABA metabolite as a possible biomarker of PTSD encourages replication in larger samples and examination of relations with symptom dimensions. Future studies also should examine whether insula GABA is a marker of anxiety proneness, cutting across clinical diagnostic categories.

Amygdala activation and symptom dimensions in obsessive-compulsive disorder

BACKGROUND

Despite knowledge of amygdala involvement in fear and anxiety, its contribution to the pathophysiology of obsessive-compulsive disorder (OCD) remains controversial. In the context of neuroimaging studies, it seems likely that the heterogeneity of the disorder might have contributed to a lack of consistent findings.

AIMS

To assess the influence of OCD symptom dimensions on amygdala responses to a well-validated emotional face-matching paradigm.

METHOD

Cross-sectional functional magnetic resonance imaging (fMRI) study of 67 patients with OCD and 67 age-, gender- and education-level matched healthy controls.

RESULTS

The severity of aggression/checking and sexual/religious symptom dimensions were significantly associated with heightened amygdala activation in those with OCD when responding to fearful faces, whereas no such correlations were seen for other symptom dimensions.

CONCLUSIONS

Amygdala functional alterations in OCD appear to be specifically modulated by symptom dimensions whose origins may be more closely linked to putative amygdala-centric processes, such as abnormal fear processing.

The functional and structural neural basis of individual differences in loss aversion

Decision making under risk entails the anticipation of prospective outcomes, typically leading to the greater sensitivity to losses than gains known as loss aversion. Previous studies on the neural bases of choice-outcome anticipation and loss aversion provided inconsistent results, showing either bidirectional mesolimbic responses of activation for gains and deactivation for losses, or a specific amygdala involvement in processing losses. Here we focused on loss aversion with the aim to address interindividual differences in the neural bases of choice-outcome anticipation. Fifty-six healthy human participants accepted or rejected 104 mixed gambles offering equal (50%) chances of gaining or losing different amounts of money while their brain activity was measured with functional magnetic resonance imaging (fMRI). We report both bidirectional and gain/loss-specific responses while evaluating risky gambles, with amygdala and posterior insula specifically tracking the magnitude of potential losses. At the individual level, loss aversion was reflected both in limbic fMRI responses and in gray matter volume in a structural amygdala-thalamus-striatum network, in which the volume of the "output" centromedial amygdala nuclei mediating avoidance behavior was negatively correlated with monetary performance. We conclude that outcome anticipation and ensuing loss aversion involve multiple neural systems, showing functional and structural individual variability directly related to the actual financial outcomes of choices. By supporting the simultaneous involvement of both appetitive and aversive processing in economic decision making, these results contribute to the interpretation of existing inconsistencies on the neural bases of anticipating choice outcomes.

Interoception and drug addiction

The role of interoception and its neural basis with relevance to drug addiction is reviewed. Interoception consists of the receiving, processing, and integrating body-relevant signals with external stimuli to affect ongoing motivated behavior. The insular cortex is the central nervous system hub to process and integrate these signals. Interoception is an important component of several addiction relevant constructs including arousal, attention, stress, reward, and conditioning. Imaging studies with drug-addicted individuals show that the insular cortex is hypo-active during cognitive control processes but hyperactive during cue reactivity and drug-specific, reward-related processes. It is proposed that interoception contributes to drug addiction by incorporating an "embodied" experience of drug uses together with the individual's predicted versus actual internal state to modulate approach or avoidance behavior, i.e. whether to take or not to take drugs. This opens the possibility of two types of interventions. First, one may be able to modulate the embodied experience by enhancing insula reactivity where necessary, e.g. when engaging in drug seeking behavior, or attenuating insula when exposed to drug-relevant cues. Second, one may be able to reduce the urge to act by increasing the frontal control network, i.e. inhibiting the urge to use by employing cognitive training. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.

How to erase memory traces of pain and fear

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Currently emerging concepts of maladaptive pain and fear suggest that they share basic neuronal circuits and cellular mechanisms of memory formation.

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Recent studies have revealed processes of erasing memory traces of pain and fear that may be promising targets for future therapies.

Pain and fear are both aversive experiences that strongly impact on behaviour and well being. They are considered protective when they lead to meaningful, adaptive behaviour such as the avoidance of situations that are potentially dangerous to the integrity of tissue (pain) or the individual (fear). Pain and fear may, however, become maladaptive if expressed under inappropriate conditions or at excessive intensities for extended durations. Currently emerging concepts of maladaptive pain and fear suggest that basic neuronal mechanisms of memory formation are relevant for the development of pathological forms of pain and fear. Thus, the processes of erasing memory traces of pain and fear may constitute promising targets for future therapies.

Fear conditioning in an abdominal pain model: neural responses during associative learning and extinction in healthy subjects

Fear conditioning is relevant for elucidating the pathophysiology of anxiety, but may also be useful in the context of chronic pain syndromes which often overlap with anxiety. Thus far, no fear conditioning studies have employed aversive visceral stimuli from the lower gastrointestinal tract. Therefore, we implemented a fear conditioning paradigm to analyze the conditioned response to rectal pain stimuli using fMRI during associative learning, extinction and reinstatement.

In N = 21 healthy humans, visual conditioned stimuli (CS⁺) were paired with painful rectal distensions as unconditioned stimuli (US), while different visual stimuli (CS⁻) were presented without US. During extinction, all CSs were presented without US, whereas during reinstatement, a single, unpaired US was presented. In region-of-interest analyses, conditioned anticipatory neural activation was assessed along with perceived CS-US contingency and CS unpleasantness.

Fear conditioning resulted in significant contingency awareness and valence change, i.e., learned unpleasantness of a previously neutral stimulus. This was paralleled by anticipatory activation of the anterior cingulate cortex, the somatosensory cortex and precuneus (all during early acquisition) and the amygdala (late acquisition) in response to the CS⁺. During extinction, anticipatory activation of the dorsolateral prefrontal cortex to the CS⁻ was observed. In the reinstatement phase, a tendency for parahippocampal activation was found.

Fear conditioning with rectal pain stimuli is feasible and leads to learned unpleasantness of previously neutral stimuli. Within the brain, conditioned anticipatory activations are seen in core areas of the central fear network including the amygdala and the anterior cingulate cortex. During extinction, conditioned responses quickly disappear, and learning of new predictive cue properties is paralleled by prefrontal activation. A tendency for parahippocampal activation during reinstatement could indicate a reactivation of the old memory trace. Together, these findings contribute to our understanding of aversive visceral learning and memory processes relevant to the pathophysiology of chronic abdominal pain.

Medial prefrontal brain activation to anticipated reward and loss in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is associated with dysfunctional brain activity in several regions which are also involved in the processing of motivational stimuli. Processing of reward and punishment appears to be of special importance to understand clinical symptoms. There is evidence for higher sensitivity to punishment in patients with OCD which raises the question how avoidance of punishment relates to activity within the brain's reward circuitry. We employed the monetary incentive delay task paradigm optimized for modeling the anticipation phase of immediate reward and punishment, in the context of a cross-sectional event-related FMRI study comparing OCD patients and healthy control participants (n = 19 in each group). While overall behavioral performance was similar in both groups, patients showed increased activation upon anticipated losses in a medial and superior frontal cortex region extending into the cingulate cortex, and decreased activation upon anticipated rewards. No evidence was found for altered activation of dorsal or ventral striatal regions. Patients also showed more delayed responses for anticipated rewards than for anticipated losses whereas the reverse was true in healthy participants. The medial prefrontal cortex has been shown to implement a domain-general process comprising negative affect, pain and cognitive control. This process uses information about punishment to control aversively motivated actions by integrating signals arriving from subcortical regions. Our results support the notion that OCD is associated with altered sensitivity to anticipated rewards and losses in a medial prefrontal region whereas there is no significant aberrant activation in ventral or dorsal striatal brain regions during processing of reinforcement anticipation.

Religious thought and behavior

While earlier approaches to religious thought and practice searched for 'magic bullet' approaches to explain religious thought and behavior, seeing it as an example of irrationality, illusion, integrative force, symbolism, or false explanations of origins, cognitive scientific approaches have suggested that we see it rather as an aggregate of the products of various cognitive mechanisms. Studies in the cognitive science of religion, informed by experimental work, have converged on a standard model of explaining religious thought and behavior by focussing on the role of minimally counter-intuitive concepts, agent and animacy detection, ritual representations, notions of contagion and contamination avoidance, theory of mind, coalitions, and moral intuitions. WIREs Cogn Sci 2012 doi: 10.1002/wcs.1189 For further resources related to this article, please visit the WIREs website.