Neural Correlates of Decisions in Quasi-Realistic, Affective Social Interactions in Individuals With Violence-Related Socialization.

Appropriate social behavior in aggressive-provocative interactions is a prerequisite for a peaceful life. In previous research, the dysfunctions of the control of aggression were suggested to be modulated by enhanced bottom-up (sub-cortically driven) and reduced top-down (iso-cortical frontal) processing capability. In the present study, two groups of individuals with enhanced (EG) and normal (NG) experiences of violent acts during their socialization made binary behavioral decisions in quasi-realistic social interactions. These interactions were presented in short video clips taken from a first-person perspective. The video clips showed social interaction scenarios oriented on realistic everyday life situations. The behavioral data supported the distinct affective qualities of three categories of social interactions. These categories were labeled as aggressive-provocative, social-positive, and neutral-social interactions. Functional neuroimaging data showed extended activation patterns and higher signal intensity for the NG compared to the EG in the lateral inferior frontal brain regions for the aggressive provocative interactions. Furthermore, the peri-aqueductal gray (PAG) produced enhanced activations for the affective interaction scenarios (i.e., aggressive-provocative and social-positive) in both groups and as a trend with the medium effect size for the neutral interactions in the EG. As the individuals in the EG did not show open aggression during the functional MRIA (fMRI) investigation, we concluded that they applied individual self-control strategies to regulate their aggressive impulses immediately. These strategies appeared to be top-down regulated through the dorsal frontal brain areas. The predominant recruitment of the heteromodal cortices during the neural processing of complex social interactions pointed to the important role of the learning history of individuals and their socialization with differing levels of violent experiences as crucial modulators in convicts. Our data suggest that building or strengthening the association between prototypical social contexts (e.g., aggressive-provocative interactions) and appropriate behaviors as a response to it provides a promising approach to successfully re-socialize people with a delinquent history.

Neural response to aggressive and positive interactions in violent offenders and nonviolent individuals.

BACKGROUND: Due to its severe negative consequences, human violence has been targeted by a vast number of studies. Yet, neurobiological mechanisms underlying violence are still widely unclear and it seems necessary to aim for high ecological validity to learn about mechanisms contributing to violence in real life. METHODS: The present functional magnetic resonance imaging (fMRI) study investigated the neurofunction of individuals with a history of violent offenses compared with that of controls using a laboratory paradigm requesting individuals to empathically engage in videos depicting provocative aggressive and positive social interactions from a first-person perspective. RESULTS: The contrast of aggressive vs. positive scenarios revealed midbrain activation patterns associated with caudal periaqueductal gray (PAG) in violent offenders; In controls, the rostral PAG was involved. Additionally, only in controls, this contrast revealed an involvement of the amygdaloidal complex. Moreover, in violent offenders the contrast of positive vs. aggressive situations revealed an involvement of areas in the insula, post-central gyrus and anterior cingulate cortex. CONCLUSIONS: Our results support findings on the differential role of PAG subdivisions in response to threat and point to altered processing of positive social interactions in violent offenders. They further support the notion that changes in PAG recruitment might contribute to violent individuals "taking action" instead of freezing in case of threatening situations.

Contextual Modulation of Binary Decisions in Dyadic Social Interactions.

The present experimental design allowed binary decisions (i.e., to choose between proactive approaching or withdrawing behavior). These decisions were made on complex social interaction scenarios displayed on videos. The videos were taken from a first-person perspective. They were preceded by one sentence each that provided additional information about the context of the displayed scenario. The sentence preceding the video and the video jointly provided a context of emotional valence. That context varied from trial to trial. We observed that provocative and threatening videos produced predominantly fear and anger responses. Fear was associated with withdrawal decisions, while anger led to approach decisions. Negative contextual information increased the probability of approach decisions in aggressive provocative videos; positive contextual information enhanced the chance of approach decisions in socially positive videos. In neutral situations, displayed in videos, the probability of the approach behavior was reduced in case of negative contextual information. Yet, the probability for approach behavior was increased if positive contextual information preceded neutral videos. Our experimental setup provided a paradigm that can be adapted and accommodated for the examination of future research questions on social decisions in multidimensional, complex social situations.

The individuality index: a measure to quantify the degree of inter-individual, spatial variability in intra-cerebral brain electric and metabolic activity.

Contemporary neuroscience research primarily focuses on the identification of brain activation patterns commonly deviant across participant groups or experimental conditions. This approach inherently underestimates potentially meaningful intra- and inter-individual variability present in brain physiological measures. We propose a parameter referred to as 'individuality index (II)' that takes individual variability into account. It quantifies the degree of individual variance of brain activation patterns for different brain regions and participants. IIs can be computed based on intra-cerebral source strength values such as the ones derived from the exact low resolution electromagnetic tomography source localization software. We exemplary estimated IIs for simulated datasets. Our results illustrate how IIs are affected by different spatial activation patterns across participants and quantify their distributional properties. They suggest that the proposed indices can meaningfully quantify inter- and intra-individuality of brain activation patterns. Their application to realistic datasets will allow the identification of (1) those brain regions that show particularly heterogeneous activation patterns, the contribution of which is particularly likely to be underestimated by conventional group statistics, (2) those brain regions that can alternatively be recruited by different participants for the same tasks, and (3) their associations with potentially decisive behavioral variables such as individually applied mental strategy.

Neural correlates of free recall of "famous events" in a "hypermnestic" individual as compared to an age- and education-matched reference group.

BACKGROUND: Memory performance of an individual (within the age range: 50-55 years old) showing superior memory abilities (protagonist PR) was compared to an age- and education-matched reference group in a historical facts ("famous events") retrieval task. RESULTS: Contrasting task versus baseline performance both PR and the reference group showed fMRI activation patterns in parietal and occipital brain regions. The reference group additionally demonstrated activation patterns in cingulate gyrus, whereas PR showed additional widespread activation patterns comprising frontal and cerebellar brain regions. The direct comparison between PR and the reference group revealed larger fMRI contrasts for PR in right frontal, superior temporal and cerebellar brain regions. CONCLUSIONS: It was concluded that PR generally recruits brain regions as normal memory performers do, but in a more elaborate way, and furthermore, that he applied a memory-strategy that potentially includes executively driven multi-modal transcoding of information and recruitment of implicit memory resources.

Differences between target and non-target probe processing--combined evidence from fMRI, EEG and fMRI-constrained source analysis.

Previous studies reported heterogeneous findings in working memory tasks when examining differences between correct recognition (targets) and correct rejection (non-targets). In the present study, twenty human participants completed a delayed match-to-sample task in two separate functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) sessions. Targets and non-target items were presented at different within-trial positions. We used fMRI-constrained source analysis to investigate the spatio-temporal neuronal dynamics of probe processing. Probe type-related differences were modulated by position in the trial or by the ratio of target stimuli to non-target stimuli at different trial positions. fMRI-constrained source analysis revealed a temporal pattern of source activities starting in occipital and temporal brain regions, followed by a simultaneous engagement of parietal and frontal brain regions and a later activity of a source in pre-SMA (supplementary motor area). Source activities demonstrated a specific involvement of left fusiform gyrus in the non-target condition compared to the target condition that might be associated with mental imagination of the target stimulus during non-target probe processing. Source activities, furthermore, showed the anterior cingulate to be particularly involved in target processing compared to non-target processing before response execution and the pre-SMA before and during response execution. These brain areas appear to be activated in different stages of conflict managing operations due to a lower stimulus frequency of target trials compared to non-target trials at different target positions in the present design.

The neural basis of impulsive discounting in pathological gamblers.

Pathological gambling is thought to result from a shift of balance between two competing neurobiological mechanisms: on the one hand the reward system involved in the regulation of the urge to get rewards and on the other hand the top-down control system. Fifteen pathological gamblers (PG) and fifteen healthy controls (HC) were studied in an event-related functional magnetic resonance imaging experiment where participants had to choose either a smaller, but immediately available monetary reward (SIR) or a larger delayed reward (LDR). We examined contrasts between LDR and SIR decisions. Additionally, we contrasted choices near the individual indifference point (indifferent decisions) and clear SIR or LDR choices (sure decisions). Behavioral data confirmed former results of steeper discount rates in PG. Contrasting choices of LDR vs. SIR showed widespread bilateral activations in PG, including postcentral gyrus, thalamus, superior/medial frontal gyrus and cingulate gyrus, whereas HC demonstrated only focal left-sided pre/postcentral activity. Forgoing an immediate reward thus recruits a widespread brain network including typical control areas. Indifferent vs. sure decisions were associated with widespread activation in PG, including the bilateral fronto-parietal cortex, insula, anterior cingulate gyrus, and striatum, whereas in HC, only bilateral frontal cortex and insula were activated. The reverse contrast demonstrated more activity for sure decisions in the cingulate gyrus, insula, and medial frontal gyrus in HC, whereas PG showed inferior parietal and superior temporal activity. The present study demonstrates that pathological gambling is associated with a shift in the interplay between a prefrontal-parietal control network and a brain network involved in immediate reward consumption.

Risk assessment and reward processing in problem gambling investigated by event-related potentials and fMRI-constrained source analysis.

BACKGROUND: The temporo-spatial dynamics of risk assessment and reward processing in problem gamblers with a focus on an ecologically valid design has not been examined previously. METHODS: We investigated risk assessment and reward processing in 12 healthy male occasional gamblers (OG) and in 12 male problem gamblers (PG) with a combined EEG and fMRI approach to identify group-differences in successively activated brain regions during two stages within a quasi-realistic blackjack game. RESULTS: Both groups did not differ in reaction times but event-related potentials in PG and OG produced significantly different amplitudes in middle and late time-windows during high-risk vs. low-risk decisions. Applying an fMRI-constrained regional source model during risk assessment resulted in larger source moments in PG in the high-risk vs. low-risk comparison in thalamic, orbitofrontal and superior frontal activations within the 600-800 ms time window. During reward processing, PG showed a trend to enhanced negativity in an early time window (100-150 ms) potentially related to higher rostral anterior cingulate activity and a trend to centro-parietal group-differences in a later time window (390-440 ms) accompanied by increased superior-frontal (i.e., premotor-related) source moments in PG vs. OG. CONCLUSIONS: We suggest that problem gambling is characterized by stronger cue-related craving during risk assessment. Reward processing is associated with early affective modulation followed by increased action preparation for ongoing gambling in PG.

Human area MT+ shows load-dependent activation during working memory maintenance with continuously morphing stimulation.

BACKGROUND: Initially, human area MT+ was considered a visual area solely processing motion information but further research has shown that it is also involved in various different cognitive operations, such as working memory tasks requiring motion-related information to be maintained or cognitive tasks with implied or expected motion.In the present fMRI study in humans, we focused on MT+ modulation during working memory maintenance using a dynamic shape-tracking working memory task with no motion-related working memory content. Working memory load was systematically varied using complex and simple stimulus material and parametrically increasing retention periods. Activation patterns for the difference between retention of complex and simple memorized stimuli were examined in order to preclude that the reported effects are caused by differences in retrieval. RESULTS: Conjunction analysis over all delay durations for the maintenance of complex versus simple stimuli demonstrated a wide-spread activation pattern. Percent signal change (PSC) in area MT+ revealed a pattern with higher values for the maintenance of complex shapes compared to the retention of a simple circle and with higher values for increasing delay durations. CONCLUSIONS: The present data extend previous knowledge by demonstrating that visual area MT+ presents a brain activity pattern usually found in brain regions that are actively involved in working memory maintenance.

Synaesthesia and sexuality: the influence of synaesthetic perceptions on sexual experience.

INTRODUCTION: Synaesthesia is a phenomenon in which a certain stimulus induces a concurrent sensory perception; it has an estimated prevalence of 4%. Sexual arousal as an inducer for synaesthetic perceptions is rarely mentioned in the literature but can be found sometimes in case reports about subjective orgasmic experiences. AIMS: To examine whether synaesthetic perceptions during sexual intercourse have an impact on the sexual experience and the extent of sexual trance compared to non-synaesthetes. METHODS: In total, 19 synaesthetes with sexual forms of synaesthesia (17 female; 2 male) were included as well as corresponding control data of 36 non-synaesthetic subjects (n = 55). Two questionnaires were used to assess relevant aspects of sexual function and dysfunction (a German adaption of the Brief Index of Sexual Functioning, KFSP) as well as the occurrence and extent of sexual trance (German version of the Altered States of Consciousness Questionnaire, OAVAV). Additionally qualitative interviews were conducted in some subjects to further explore the nature of sexual experiences in synaesthetes. MAIN OUTCOME MEASURES: Sexual experience and extent of sexual trance during intercourse. RESULTS: Synaesthetes depicted significantly better overall sexual function on the KFSP with increased scores for the subscale "sexual appetence" but coevally significant lower subscale scores for "sexual satisfaction." Sexual dysfunction was not detected in this sample. Synaesthetes depicted significantly higher levels of the subscales "oceanic boundlessness" and "visionary restructuralization" than controls using the OAVAV. Qualitative interviews revealed varying synaesthetic perceptions during the different states of arousal. Furthermore, synaesthetes reported an unsatisfactory feeling of isolation caused by the idiosyncratic perceptions. CONCLUSIONS: Synaesthetes with sexual forms of synaesthesia seem to experience a deeper state of sexual trance without, however, enhanced satisfaction during sexual intercourse.

The perception of dynamic and static facial expressions of happiness and disgust investigated by ERPs and fMRI constrained source analysis.

A recent functional magnetic resonance imaging (fMRI) study by our group demonstrated that dynamic emotional faces are more accurately recognized and evoked more widespread patterns of hemodynamic brain responses than static emotional faces. Based on this experimental design, the present study aimed at investigating the spatio-temporal processing of static and dynamic emotional facial expressions in 19 healthy women by means of multi-channel electroencephalography (EEG), event-related potentials (ERP) and fMRI-constrained regional source analyses. ERP analysis showed an increased amplitude of the LPP (late posterior positivity) over centro-parietal regions for static facial expressions of disgust compared to neutral faces. In addition, the LPP was more widespread and temporally prolonged for dynamic compared to static faces of disgust and happiness. fMRI constrained source analysis on static emotional face stimuli indicated the spatio-temporal modulation of predominantly posterior regional brain activation related to the visual processing stream for both emotional valences when compared to the neutral condition in the fusiform gyrus. The spatio-temporal processing of dynamic stimuli yielded enhanced source activity for emotional compared to neutral conditions in temporal (e.g., fusiform gyrus), and frontal regions (e.g., ventromedial prefrontal cortex, medial and inferior frontal cortex) in early and again in later time windows. The present data support the view that dynamic facial displays trigger more information reflected in complex neural networks, in particular because of their changing features potentially triggering sustained activation related to a continuing evaluation of those faces. A combined fMRI and EEG approach thus provides an advanced insight to the spatio-temporal characteristics of emotional face processing, by also revealing additional neural generators, not identifiable by the only use of an fMRI approach.

Multiple routes to mental animation: language and functional relations drive motion processing for static images.

When looking at static visual images, people often exhibit mental animation, anticipating visual events that have not yet happened. But what determines when mental animation occurs? Measuring mental animation using localized brain function (visual motion processing in the middle temporal and middle superior temporal areas, MT+), we demonstrated that animating static pictures of objects is dependent both on the functionally relevant spatial arrangement that objects have with one another (e.g., a bottle above a glass vs. a glass above a bottle) and on the linguistic judgment to be made about those objects (e.g., "Is the bottle above the glass?" vs. "Is the bottle bigger than the glass?"). Furthermore, we showed that mental animation is driven by functional relations and language separately in the right hemisphere of the brain but conjointly in the left hemisphere. Mental animation is not a unitary construct; the predictions humans make about the visual world are driven flexibly, with hemispheric asymmetry in the routes to MT+ activation.

A hybrid model for the neural representation of complex mental processing in the human brain.

In the present conceptual review several theoretical and empirical sources of information were integrated, and a hybrid model of the neural representation of complex mental processing in the human brain was proposed. Based on empirical evidence for strategy-related and inter-individually different task-related brain activation networks, and further based on empirical evidence for a remarkable overlap of fronto-parietal activation networks across different complex mental processes, it was concluded by the author that there might be innate and modular organized neuro-developmental starting regions, for example, in intra-parietal, and both medial and middle frontal brain regions, from which the neural organization of different kinds of complex mental processes emerge differently during individually shaped learning histories. Thus, the here proposed model provides a hybrid of both massive modular and holistic concepts of idiosyncratic brain physiological elaboration of complex mental processing. It is further concluded that 3-D information, obtained by respective methodological approaches, are not appropriate to identify the non-linear spatio-temporal dynamics of complex mental process-related brain activity in a sufficient way. How different participating network parts communicate with each other seems to be an indispensable aspect, which has to be considered in particular to improve our understanding of the neural organization of complex cognition.

The neural architecture of expert calendar calculation: a matter of strategy?

Savants and prodigies are individuals with exceptional skills in particular mental domains. In the present study we used functional magnetic resonance imaging to examine neural correlates of calendar calculation in two individuals, a savant with Asperger's disorder and a self-taught mathematical prodigy. If there is a modular neural organization of exceptional performance in a specific mental domain, calendar calculation should be reflected in a considerable overlap in the recruitment of brain circuits across expert individuals. However, considerable individual differences in activation patterns during calendar calculation were noted. The present results indicate that activation patterns produced by complex mental processing, such as calendar calculation, seem to be influenced strongly by learning history and idiosyncratic strategy usage rather than a modular neural organization. Thus, well-known individual differences in complex cognition play a major role even in experts with exceptional abilities in a particular mental domain and should in particular be considered when examining the neural architecture of complex mental processes and skills.

Neurobiological correlates of problem gambling in a quasi-realistic blackjack scenario as revealed by fMRI.

In the present study we obtained functional magnetic resonance imaging (fMRI) data in occasional gamblers (OG) and problem gamblers (PG) during a quasi-realistic blackjack game. We focused on neuronal correlates of risk assessment and reward processing. Participants had to decide whether to draw or not to draw a card in a high-risk or low-risk blackjack situation. We assumed PG would show differences in prefrontal and ventral striatal brain regions in comparison to OG during risk assessment and due to the winning or losing of money. Although both groups did not differ in behavioral data, blood oxygen level dependent (BOLD) signals in PG and OG significantly differed in thalamic, inferior frontal, and superior temporal regions. Whereas PG demonstrated a consistent signal increase during high-risk situations and a decrease in low-risk situations, OG presented the opposite pattern. During reward processing as derived from contrasting winning vs. losing situations, both PG and OG groups showed an enhancement of ventral striatal and posterior cingulate activity. Furthermore, PG demonstrated a distinct fronto-parietal activation pattern which has been discussed to reflect a cue-induced addiction memory network which was triggered by gambling-related cues.

Neural correlates in exceptional mental arithmetic--about the neural architecture of prodigious skills.

Prodigies are individuals with exceptional mental abilities. How is it possible that some of these people mentally calculate exponentiations with high accuracy and speed? We examined CP, a mental calculation prodigy, and a control group of 11 normal calculators for moderate mental arithmetic tasks. CP has additionally been tested for exceptionally difficult exponentiations. We hypothesized that, if CP would activate similar brain regions as controls for both moderate and very difficult tasks, his special exceptional abilities could rather be explained by neuroplastic changes as a result of obsessive practice than by unusual mental strategies and/or neurocognitive mechanisms. For very difficult exponentiation tasks, CP showed activation patterns in brain regions adjacent to those, which were activated for moderate task calculation by both CP and control participants. We concluded, therefore, that CP's exceptional calculation performance might rather be based on neuroplastic changes substantially caused by years of daily hours of training combined with excellent working memory capabilities and not on the recruitment of additional brain mechanisms. Furthermore, but considering that only one prodigy was compared with a control group, results of the present study imply that the neural substrate, which is potentially necessary to enhance specific skills dramatically by positively motivated excessive mental training, might be present in every healthy individual.

The neural processing of voluntary completed, real and virtual violent and nonviolent computer game scenarios displaying predefined actions in gamers and nongamers.

Studies investigating the effects of violent computer and video game playing have resulted in heterogeneous outcomes. It has been assumed that there is a decreased ability to differentiate between virtuality and reality in people that play these games intensively. FMRI data of a group of young males with (gamers) and without (controls) a history of long-term violent computer game playing experience were obtained during the presentation of computer game and realistic video sequences. In gamers the processing of real violence in contrast to nonviolence produced activation clusters in right inferior frontal, left lingual and superior temporal brain regions. Virtual violence activated a network comprising bilateral inferior frontal, occipital, postcentral, right middle temporal, and left fusiform regions. Control participants showed extended left frontal, insula and superior frontal activations during the processing of real, and posterior activations during the processing of virtual violent scenarios. The data suggest that the ability to differentiate automatically between real and virtual violence has not been diminished by a long-term history of violent video game play, nor have gamers' neural responses to real violence in particular been subject to desensitization processes. However, analyses of individual data indicated that group-related analyses reflect only a small part of actual individual different neural network involvement, suggesting that the consideration of individual learning history is sufficient for the present discussion.

Emotions in motion: dynamic compared to static facial expressions of disgust and happiness reveal more widespread emotion-specific activations.

In social contexts, facial expressions are dynamic in nature and vary rapidly in relation to situational requirements. However, there are very few fMRI studies using dynamic emotional stimuli. The aim of this study was (1) to introduce and evaluate a new stimulus database of static and dynamic emotional facial expressions according to arousal and recognizability investigated by a rating by both participants of the present fMRI study and by an external sample of 30 healthy women, (2) to examine the neural networks involved in emotion perception of static and dynamic facial stimuli separately, and (3) to examine the impact of motion on the emotional processing of dynamic compared to static face stimuli. A total of 16 females participated in the present fMRI study performing a passive emotion perception task including static and dynamic faces of neutral, happy and disgusted expressions. Comparing dynamic stimuli to static faces indicated enhanced emotion-specific brain activation patterns in the parahippocampal gyrus (PHG) including the amygdala (AMG), fusiform gyrus (FG), superior temporal gyrus (STG), inferior frontal gyrus (IFG), and occipital and orbitofrontal cortex (OFC). These regions have been discussed to be associated with emotional memory encoding, the perception of threat, facial identity, biological motion, the mirror neuron system, an increase of emotional arousal, and reward processing, respectively. Post hoc ratings of the dynamic stimuli revealed a better recognizability in comparison to the static stimuli. In conclusion, dynamic facial expressions might provide a more appropriate approach to examine the processing of emotional face perception than static stimuli.