Detecting Analogies Unconsciously

Analogies may arise from the conscious detection of similarities between a present and a past situation. In this functional magnetic resonance imaging study, we tested whether young volunteers would detect analogies unconsciously between a current supraliminal (visible) and a past subliminal (invisible) situation. The subliminal encoding of the past situation precludes awareness of analogy detection in the current situation. First, participants encoded subliminal pairs of unrelated words in either one or nine encoding trials. Later, they judged the semantic fit of supraliminally presented new words that either retained a previously encoded semantic relation (“analog”) or not (“broken analog”). Words in analogs versus broken analogs were judged closer semantically, which indicates unconscious analogy detection. Hippocampal activity associated with subliminal encoding correlated with the behavioral measure of unconscious analogy detection. Analogs versus broken analogs were processed with reduced prefrontal but enhanced medial temporal activity. We conclude that analogous episodes can be detected even unconsciously drawing on the episodic memory network.

Neural correlates of evaluating hazards of high risk.

In personal and in society related context, people often evaluate the risk of environmental and technological hazards. Previous research addressing neuroscience of risk evaluation assessed particularly the direct personal risk of presented stimuli, which may have comprised for instance aspects of fear. Further, risk evaluation primarily was compared to tasks of other cognitive domains serving as control conditions, thus revealing general risk related brain activity, but not such specifically associated with estimating a higher level of risk. We here investigated the neural basis on which lay-persons individually evaluated the risk of different potential hazards for the society. Twenty healthy subjects underwent functional magnetic resonance imaging while evaluating the risk of fifty more or less risky conditions presented as written terms. Brain activations during the individual estimations of 'high' against 'low' risk, and of negative versus neutral and positive emotional valences were analyzed. Estimating hazards to be of high risk was associated with activation in medial thalamus, anterior insula, caudate nucleus, cingulate cortex and further prefrontal and temporo-occipital areas. These areas were not involved according to an analysis of the emotion ratings. In conclusion, we emphasize a contribution of the mentioned brain areas involved to signal high risk, here not primarily associated with the emotional valence of the risk items. These areas have earlier been reported to be associated with, beside emotional, viscerosensitive and implicit processing. This leads to assumptions of an intuitive contribution, or a "gut-feeling", not necessarily dependent of the subjective emotional valence, when estimating a high risk of environmental hazards.

Assessing the function of the fronto-parietal attention network: Insights from resting-state fMRI and the attentional network test

In the recent past, various intrinsic connectivity networks (ICN) have been identified in the resting brain. It has been hypothesized that the fronto-parietal ICN is involved in attentional processes. Evidence for this claim stems from task-related activation studies that show a joint activation of the implicated brain regions during tasks that require sustained attention. In this study, we used functional magnetic resonance imaging (fMRI) to demonstrate that functional connectivity within the fronto-parietal network at rest directly relates to attention. We applied graph theory to functional connectivity data from multiple regions of interest and tested for associations with behavioral measures of attention as provided by the attentional network test (ANT), which we acquired in a separate session outside the MRI environment. We found robust statistical associations with centrality measures of global and local connectivity of nodes within the network with the alerting and executive control subfunctions of attention. The results provide further evidence for the functional significance of ICN and the hypothesized role of the fronto-parietal attention network. Hum Brain Mapp , 2013. © 2013 Wiley Periodicals, Inc.

Interactions between dorsolateral and ventromedial prefrontal cortex underlie context-dependent stimulus valuation in goal-directed choice.

External circumstances and internal bodily states often change and require organisms to flexibly adapt valuation processes to select the optimal action in a given context. Here, we investigate the neurobiology of context-dependent valuation in 22 human subjects using functional magnetic resonance imaging. Subjects made binary choices between visual stimuli with three attributes (shape, color, and pattern) that were associated with monetary values. Context changes required subjects to deviate from the default shape valuation and to integrate a second attribute in order to comply with the goal to maximize rewards. Critically, this binary choice task did not involve any conflict between opposing monetary, temporal, or social preferences. We tested the hypothesis that interactions between regions of dorsolateral and ventromedial prefrontal cortex (dlPFC; vmPFC) implicated in self-control choices would also underlie the more general function of context-dependent valuation. Consistent with this idea, we found that the degree to which stimulus attributes were reflected in vmPFC activity varied as a function of context. In addition, activity in dlPFC increased when context changes required a reweighting of stimulus attribute values. Moreover, the strength of the functional connectivity between dlPFC and vmPFC was associated with the degree of context-specific attribute valuation in vmPFC at the time of choice. Our findings suggest that functional interactions between dlPFC and vmPFC are a key aspect of context-dependent valuation and that the role of this network during choices that require self-control to adjudicate between competing outcome preferences is a specific application of this more general neural mechanism.

Neural circuits of emotion regulation: a comparison of mindfulness-based and cognitive reappraisal strategies

Dealing with one's emotions is a core skill in everyday life. Effective cognitive control strategies have been shown to be neurobiologically represented in prefrontal structures regulating limbic regions. In addition to cognitive strategies, mindfulness-associated methods are increasingly applied in psychotherapy. We compared the neurobiological mechanisms of these two strategies, i.e. cognitive reappraisal and mindfulness, during both the cued expectation and perception of negative and potentially negative emotional pictures. Fifty-three healthy participants were examined with functional magnetic resonance imaging (47 participants included in analysis). Twenty-four subjects applied mindfulness, 23 used cognitive reappraisal. On the neurofunctional level, both strategies were associated with comparable activity of the medial prefrontal cortex and the amygdala. When expecting negative versus neutral stimuli, the mindfulness group showed stronger activations in ventro- and dorsolateral prefrontal cortex, supramarginal gyrus as well as in the left insula. During the perception of negative versus neutral stimuli, the two groups only differed in an increased activity in the caudate in the cognitive group. Altogether, both strategies recruited overlapping brain regions known to be involved in emotion regulation. This result suggests that common neural circuits are involved in the emotion regulation by mindfulness-based and cognitive reappraisal strategies. Identifying differential activations being associated with the two strategies in this study might be one step towards a better understanding of differential mechanisms of change underlying frequently used psychotherapeutic interventions.

Neural representation and clinically relevant moderators of individualised self-criticism in healthy subjects

Many people routinely criticise themselves. While self-criticism is largely unproblematic for most individuals, depressed patients exhibit excessive self-critical thinking, which leads to strong negative affects. We used functional magnetic resonance imaging in healthy subjects (N = 20) to investigate neural correlates and possible psychological moderators of self-critical processing. Stimuli consisted of individually selected adjectives of personally negative content and were contrasted with neutral and negative non-self-referential adjectives. We found that confrontation with self-critical material yielded neural activity in regions involved in emotions (anterior insula/hippocampus-amygdala formation) and in anterior and posterior cortical midline structures, which are associated with self-referential and autobiographical memory processing. Furthermore, contrasts revealed an extended network of bilateral frontal brain areas. We suggest that the co-activation of superior and inferior lateral frontal brain regions reflects the recruitment of a frontal top-down pathway, representing cognitive reappraisal strategies for dealing with evoked negative affects. In addition, activation of right superior frontal areas was positively associated with neuroticism and negatively associated with cognitive reappraisal. Although these findings may not be specific to negative stimuli, they support a role for clinically relevant personality traits in successful regulation of emotion during confrontation with self-critical material.

BDNF Val66Met polymorphism influence on striatal blood-level-dependent response to monetary feedback depends on valence and agency

Animal work implicates the brain-derived neurotrophic factor (BDNF) in function of the ventral striatum (VS), a region known for its role in processing valenced feedback. Recent evidence in humans shows that BDNF Val66Met polymorphism modulates VS activity in anticipation of monetary feedback. However, it remains unclear whether the polymorphism impacts the processing of self-attributed feedback differently from feedback attributed to an external agent. In this study, we emphasize the importance of the feedback attribution because agency is central to computational accounts of the striatum and cognitive accounts of valence processing. We used functional magnetic resonance imaging and a task, in which financial gains/losses are either attributable to performance (self-attributed, SA) or chance (externally-attributed, EA) to ask whether BDNF Val66Met polymorphism predicts VS activity. We found that BDNF Val66Met polymorphism influenced how feedback valence and agency information were combined in the VS and in the right inferior frontal junction (IFJ). Specifically, Met carriers' VS response to valenced feedback depended on agency information, while Val/Val carriers' VS response did not. This context-specific modulation of valence effectively amplified VS responses to SA losses in Met carriers. The IFJ response to SA losses also differentiated Val/Val from Met carriers. These results may point to a reduced allocation of attention and altered motivational salience to SA losses in Val/Val compared to Met carriers. Implications for major depressive disorder are discussed.

Rivalry of homeostatic and sensory-evoked emotions: dehydration attenuates olfactory disgust and its neural correlates

Neural correlates have been described for emotions evoked by states of homeostatic imbalance (e.g. thirst, hunger, and breathlessness) and for emotions induced by external sensory stimulation (such as fear and disgust). However, the neurobiological mechanisms of their interaction, when they are experienced simultaneously, are still unknown. We investigated the interaction on the neurobiological and the perceptional level using subjective ratings, serum parameters, and functional magnetic resonance imaging (fMRI) in a situation of emotional rivalry, when both a homeostatic and a sensory-evoked emotion were experienced at the same time. Twenty highly dehydrated male subjects rated a disgusting odor as significantly less repulsive when they were thirsty. On the neurobiological level, we found that this reduction in subjective disgust during thirst was accompanied by a significantly reduced neural activity in the insular cortex, a brain area known to be considerably involved in processing of disgust. Furthermore, during the experience of disgust in the satiated condition, we observed a significant functional connectivity between brain areas responding to the disgusting odor, which was absent during the stimulation in the thirsty condition. These results suggest interference of conflicting emotions: An acute homeostatic imbalance can attenuate the experience of another emotion evoked by the sensory perception of a potentially harmful external agent. This finding offers novel insights with regard to the behavioral relevance of biologically different types of emotions, indicating that some types of emotions are more imperative for behavior than others. As a general principle, this modulatory effect during the conflict of homeostatic and sensory-evoked emotions may function to safeguard survival.

An fMRI-Study on context-specificity of inhibitory functions in alcohol-dependency: Preliminary results

Introduction: Alcohol-dependency is a common disease with many negative consequences in the daily life. A typical symptom of alcoholic-patients is the persistent and uncontrollable desire to consume alcohol. Inspite of different treatments, alcohol-dependency has a relapse rate of about 85%. This high rate is facilitated by a dysfunction of cognitive control-processes. In order to understand this disease sustaining factor, the present study investigated the neurophysiological correlates of inhibition of alcoholic-patients in a neutral as well as an alcohol-related context. Methods: A total of 18 participants, (9 alcohol-dependent-patients (age range: 27-62 years), 9 healthy controls (age range: 29-60 years)) have been measured with functional magnetic resonance imaging while they participated in an alcohol-specific Go/NoGo-Task. Neurophysiological correlates of inhibition in an alcohol-related as well as a neutral context were compared in both groups. Results: When comparing correct stop-trials in alcohol-related to neutral context, only alcohol-dependent patients showed significant hyperactivation in frontal regions (superior and medial gyrus frontalis, anterior gyrus cinguli, gyrus paracentralis and the gyrus praecentralis). No significant differences were found in any of the behavioral analyses. Discussion: These preliminary results thus indicate that successful inhibition in a drug-related context demands additional resources in patients. Especially the hyperactivation of the anterior gyrus cinguli might be important because of its involvement in decision-processes. In the absent of deficits in behavioral data, this suggests that alcohol-dependent patients need more neuronal activity to achieve the same performance-level like healthy controls.

Cortical reorganisation of cerebral networks after childhood stroke: impact on outcome.

BACKGROUND Recovery after arterial ischaemic stroke is known to largely depend on the plastic properties of the brain. The present study examines changes in the network topography of the developing brain after stroke. Effects of brain damage are best assessed by examining entire networks rather than single sites of structural lesions. Relating these changes to post-stroke neuropsychological variables and motor abilities will improve understanding of functional plasticity after stroke. Inclusion of healthy controls will provide additional insight into children's normal brain development. Resting state functional magnetic resonance imaging is a valid approach to topographically investigate the reorganisation of functional networks after a brain lesion. Transcranial magnetic stimulation provides complementary output information. This study will investigate functional reorganisation after paediatric arterial ischaemic stroke by means of resting state functional magnetic resonance imaging and transcranial magnetic stimulation in a cross-sectional plus longitudinal study design. The general aim of this study is to better understand neuroplasticity of the developing brain after stroke in order to develop more efficacious therapy and to improve the post-stroke functional outcome. METHODS The cross-sectional part of the study will investigate the functional cerebral networks of 35 children with chronic arterial ischaemic stroke (time of the lesion >2 years). In the longitudinal part, 15 children with acute arterial ischaemic stroke (shortly after the acute phase of the stroke) will be included and investigations will be performed 3 times within the subsequent 9 months. We will also recruit 50 healthy controls, matched for age and sex. The neuroimaging and neurophysiological data will be correlated with neuropsychological and neurological variables. DISCUSSION This study is the first to combine resting state functional magnetic resonance imaging and transcranial magnetic stimulation in a paediatric population diagnosed with arterial ischaemic stroke. Thus, this study has the potential to uniquely contribute to the understanding of neuronal plasticity in the brains of healthy children and those with acute or chronic brain injury. It is expected that the results will lead to the development of optimal interventions after arterial ischaemic stroke.

Limbic brain responses in mothers with post-traumatic stress disorder and comorbid dissociation to video clips of their children.

Maternal dissociative symptoms which can be comorbid with interpersonal violence-related post-traumatic stress disorder (IPV-PTSD) have been linked to decreased sensitivity and responsiveness to children's emotional communication. This study examined the influence of dissociation on neural activation independently of IPV-PTSD symptom severity when mothers watch video-stimuli of their children during stressful and non-stressful mother-child interactions. Based on previous observations in related fields, we hypothesized that more severe comorbid dissociation in IPV-PTSD would be associated with lower limbic system activation and greater neural activity in regions of the emotion regulation circuit such as the medial prefrontal cortex and dorsolateral prefrontal cortex (dlPFC). Twenty mothers (of children aged 12-42 months), with and without IPV-PTSD watched epochs showing their child during separation and play while undergoing functional magnetic resonance imaging (fMRI). Multiple regression indicated that when mothers diagnosed with IPV-PTSD watched their children during separation compared to play, dissociative symptom severity was indeed linked to lowered activation within the limbic system, while greater IPV-PTSD symptom severity was associated with heightened limbic activity. Concerning emotion regulation areas, there was activation associated to dissociation in the right dlPFC. Our results are likely a neural correlate of affected mothers' reduced capacity for sensitive responsiveness to their young child following exposure to interpersonal stress, situations that are common in day-to-day parenting.

Great expectations: what can fMRI research tell us about psychological phenomena?

Expectations for what functional magnetic resonance imaging (fMRI) can offer psychophysiology vary greatly. Overreaching enthusiasm such as the idea that fMRI can reveal lies and political attitudes are as common as the opinion that fMRI, in its current form, is useless for the advancement of psychological theories. Errors in the inferences being drawn from fMRI data may be contributing to each of these extreme positions, so the present paper addresses these several common inferential errors and describes some of the potential of fMRI for psychophysiological theory and research.

Differential recruitment of brain networks during visuospatial and color processing: Evidence from ERP microstates

Recent functional magnetic resonance imaging (fMRI) studies consistently revealed contributions of fronto-parietal and related networks to the execution of a visuospatial judgment task, the so-called "Clock Task". However, due to the low temporal resolution of fMRI, the exact cortical dynamics and timing of processing during task performance could not be resolved until now. In order to clarify the detailed cortical activity and temporal dynamics, 14 healthy subjects performed an established version of the "Clock Task", which comprises a visuospatial task (angle discrimination) and a control task (color discrimination) with the same stimulus material, in an electroencephalography (EEG) experiment. Based on the time-resolved analysis of network activations (microstate analysis), differences in timing between the angle compared to the color discrimination task were found after sensory processing in a time window starting around 200ms. Significant differences between the two tasks were observed in an analysis window from 192ms to 776ms. We divided this window in two parts: an early phase - from 192ms to ∼440ms, and a late phase - from ∼440ms to 776ms. For both tasks, the order of network activations and the types of networks were the same, but, in each phase, activations for the two conditions were dominated by differing network states with divergent temporal dynamics. Our results provide an important basis for the assessment of deviations in processing dynamics during visuospatial tasks in clinical populations.

Exploring the emotional brain: Neural correlates of homeostatic and sensory-evoked emotions and their interaction in emotional rivalry

Human emotions are essential for survival. They are vital for the satisfaction of basic needs, the regulation of personal life and successful integration into social structures. Depending on which aspect of an emotion is used in its definition, many different theories offer possible answers to the questions of what emotions are and how they can be distinguished. The systematic investigation of emotions in cognitive neuroscience is relatively new, and neuroimaging studies specifically focussing on the neural correlates of different categories of emotions are still lacking. Therefore, the current thesis aimed at investigating the behavioural and neurophysiological correlates of different human emotional levels and their interaction in healthy subjects. We differentiated between emotions according to their cerebral entry site and neural processing pathways: homeostatic emotions, which are elicited by metabolic changes and processed by the interoceptive system (such as thirst, hunger, and need for air), and sensory-evoked emotions, which are evoked by external inputs via the eyes, ears or nose, or their corresponding mental representations and processed in the brain as sensory perception (e.g. fear, disgust, or pride). Using functional magnetic resonance imaging (fMRI) and behavioural parameters, we examined both the specific neural underpinnings of a homeostatic emotion (thirst) and a sensory-evoked emotion (disgust), and their interaction in a situation of emotional rivalry when both emotions were perceived simultaneously. This thesis comprises three research articles reporting the results of this research. The first paper presents disgust-related brain imaging data in a thirsty and a satiated condition. We found that disgust mainly activated the anterior insular cortex. In the thirsty condition, however, we observed an interaction effect between disgust and thirst: when thirsty, the subjects rated the disgusting stimulus as less repulsive. On the neurobiological level, this reduction of subjective disgust was accompanied by significantly reduced neural activity in the insular cortex. These results provide new neurophysiological evidence for a hierarchical organization among homeostatic and sensory-evoked emotions, revealing that in a situation of emotional conflict, homeostatic emotions are prioritized over sensory-evoked emotions. In the second paper, findings on brain perfusion over four different thirst stages are reported, with a special focus on the parametric progression of thirst. Cerebral perfusion differences over all thirst stages were found in the posterior insular cortex. Taking this result together with the findings of the first paper, the insular cortex seems to be a key player in human emotional processing, since it comprises specific representations of homeostatic and sensory-evoked emotions and also represents the site of cortical interaction between the two levels of emotions. Finally, although this thesis focussed on the homeostatic modulation of disgust, we were also interested in whether dehydration modulates taste perception. The results of this behavioural experiment are described in the third paper, where we show that dehydration alters the perception of neutral taste stimuli.

Amygdala response to self-critical stimuli and symptom improvement in psychotherapy for depression

Background: Cognitive–behavioural therapy is efficacious in the treatment of major depressive disorder but response rates are still far from satisfactory. Aims: To better understand brain responses to individualised emotional stimuli and their association with outcome, to enhance treatment. Method: Functional magnetic resonance imaging data were collected prior to individual psychotherapy. Differences in brain activity during passive viewing of individualised self-critical material in 23 unmedicated out-patients with depression and 28 healthy controls were assessed. The associations between brain activity, cognitive and emotional change, and outcome were analysed in 21 patients. Results: Patients showed enhanced activity in the amygdala and ventral striatum compared with the control group. Non-response to therapy was associated with enhanced activity in the right amygdala compared with those who responded, and activity in this region was negatively associated with outcome. Emotional but not cognitive changes mediated this association. Conclusions: Amygdala hyperactivity may lessen symptom improvement in psychotherapy for depression through attenuating emotional skill acquisition.