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Das ereigniskorrelierte Potential (EKP) P300 ist eines der am häufigsten untersuchten Potentiale des Elektroenzephalogramms (EEG). Wegen der bedeutsamen Rolle der P300 in der kognitiven Forschung mit gesunden Probanden und psychiatrischen Patienten kommt der Suche nach ihren neuronalen Generatoren ein hoher Stellenwert zu. Man geht im Allgemeinen davon aus, dass sie kein einheitliches Potential darstellt und von mehreren weit verstreuten Quellen generiert wird. Die Fragen nach der genauen Anzahl der P300-Subkomponenten, ihrer Lokalisierung sowie den ihnen zugrunde liegenden kognitiven Prozesse sind jedoch nach wie vor ungelöst. Die Zielsetzung der vorliegenden Arbeit war, die P300 mit Hilfe der Kombination vom EEG und der funktionalen Magnetresonanztomografie (fMRT) in ihre Subkomponenten zu untergliedern und deren Quellen zu lokalisieren. Zu diesem Zweck wurden drei kombinierte EEG/fMRT-Studien durchgeführt. Die ersten beiden Studien beinhalten eine abgewandelte Form des klassischen Oddballparadigmas. Bei der dritten Studie handelt es sich um ein Arbeitsgedächtnisexperiment. Durch die Verknüpfung der fMRT-Ergebnisse mit EKP-Daten aus den beiden Oddball-Experimenten konnten die neuronalen Quellen der zwei wichtigsten Subkomponenten der P300, der P3a und P3b, lokalisiert werden. Es konnte gezeigt werden, dass inferiore und posteriore parietale (IPL bzw. PPC) und inferior temporale (IT) Areale zur Entstehung der P3b beitrugen, während hauptsächlich die präzentralen Regionen (PrCS) die P3a generierten. Die Ergebnisse des Arbeitsgedächtnisexperiments bestätigten die P3b-Quellenlokalisierung der Oddball-Untersuchung mit einr Beteiligung von PPC und IT an der Generierung der P3b-Komponente. Das Arbeitsgedächtnisexperiment verdeutlichte aber auch, dass eine komplexere Abrufanforderung (mit langen Reaktionszeiten) zu einer anhaltenden Aktivität im PPC und einer späten Antwort im ventrolateralen präfrontalen Kortex (VLPFC) führte, die eine zweite P3b-Subkomponente generierten. Durch eine umfassende zeitlich-räumliche Trennung der neuronalen Aktivität beim Arbeitsgedächtnisabruf konnten darüber hinaus die einzelnen Stufen der beteiligten Informationsverarbeitungsprozesse (mentale Chronometrie) beschrieben werden. Diese Anwendung ging über die „reine“ Quellenlokalisation der P300-Komponenten hinaus. Die Ergebnisse zeigten frühe transiente Aktivierungen im IT, die sich zeitlich mit dem Beginn einer anhaltenden Aktivität im PPC überlappten. Darüber hinaus wurden eine späte transiente Aktivität im VLPFC und eine späte anhaltende Aktivität im medialen frontalen und motorischen Kortex (MFC bzw. MC) beobachtet. Es liegt nahe, dass diese neuronalen Signaturen einzelne Stufen kognitiver Aufgabenverarbeitungsschritte wie Reizevaluation (IT), Operationen am Gedächtnispuffer (PPC), aktiven Abruf (VLPFC) und Reaktionsorganisation (MFC und MC) reflektieren. Die vorgestellten Quellenmodelle zeigten übereinstimmend, dass mehrere kortikale Generatoren das P300-EKP erzeugen. Dabei trugen neben den erwarteten parietalen interessanterweise auch inferior temporale und inferior frontale Quellen zur P3b bei, während die P3a vor allem auf anterioren Generatoren im prämotorischen Kortex basierte. Diese Ergebnisse bestätigen teilweise die bisherigen Lokalisationsmodelle, die weitgehend auf neuropsychologischen und invasiven neurophysiologischen Befunden beruhen, widersprechen ihnen aber auch zum Teil, besonders was die Abwesenheit der postulierten präfrontalen und hippocampalen Beiträge zur P3a bzw. P3b betrifft.
Adolescence has been linked to an enhanced tolerance of uncertainty and risky behavior and is possibly connected to an increased response toward rewards. However, previous research has produced inconsistent findings. To investigate whether these findings are due to different reward probabilities used in the experimental design, we extended a monetary incentive delay (MID) task by including three different reward probabilities. Using functional magnetic resonance imaging, 25 healthy adolescents and 22 adults were studied during anticipation of rewards in the VS. Differently colored cue stimuli indicated either a monetary or verbal trial and symbolized different reward probabilities, to which the participants were blinded. Results demonstrated faster reaction times for lower reward probabilities (33%) in both age groups. Adolescents were slower through all conditions and had less activation on a neural level. Imaging results showed a three-way interaction between age group x condition x reward probability with differences in percent signal change between adolescents and adults for the high reward probabilities (66%, 88%) while adolescents demonstrated differences for the lowest (33%). Therefore, previous inconsistent findings could be due to different reward probabilities, which makes examining these crucial for a better understanding of adolescent and adult behavior.
Methods for dichoptic stimulus presentation in functional magnetic resonance imaging : a review
(2009)
Dichoptic stimuli (different stimuli displayed to each eye) are increasingly being used in functional brain imaging experiments using visual stimulation. These studies include investigation into binocular rivalry, interocular information transfer, three-dimensional depth perception as well as impairments of the visual system like amblyopia and stereodeficiency. In this paper, we review various approaches of displaying dichoptic stimulus used in functional magnetic resonance imaging experiments. These include traditional approaches of using filters (red-green, red-blue, polarizing) with optical assemblies as well as newer approaches of using bi-screen goggles.
Bipolar disorder (BD) and major depressive disorder (MDD) are severe mood disorders that belong to the most debilitating diseases worldwide. Differentiating both mood disorders often poses a major clinical challenge, leading to frequent misdiagnoses. Objective biomarkers able to differentiate individuals with BD and MDD therefore represent a psychiatric research field of utmost importance. Recent studies have applied resting-state fMRI paradigms and found promising results differentiating both disorders based on the acquired data. However, most of these studies have focused their efforts on acutely depressed patients. Thus, it remains unclear whether the aberrations remain in a symptomless disease state.
The here presented study addresses these issues by evaluating the ability to differentiate both disorders from one another by conducting a between-group comparison of functional brain network connectivity (FNC) obtained from resting-state fMRI data. Data were collected from 20 BD, 15 MDD patients and 30 age- and gender-matched healthy controls (HC). Graph theoretical analyses were applied to detect differences in functional network organization between the groups on a global and regional network level.
Network analysis detected frontal, temporal and subcortical nodes in emotion regulation areas such as the limbic system and associated regions exhibiting significant differences in network integration and segregation in BD compared to MDD patients and HC. Participants with MDD and HC only differed in frontal and insular network centrality.
These results indicate that a significantly altered brain network topology in the limbic system might be a trait marker specific to BD. Brain network analysis in these regions may therefore be used to differentiate euthymic BD not only from HC but also from patients with MDD.
Introduction: Previous studies have established graph theoretical analysis of functional network connectivity (FNC) as a potential tool to detect neurobiological underpinnings of psychiatric disorders. Despite the promising outcomes in studies that examined FNC aberrancies in bipolar disorder (BD) and major depressive disorder (MDD), there is still a lack of research comparing both mood disorders, especially in a nondepressed state. In this study, we used graph theoretical network analysis to compare brain network properties of euthymic BD, euthymic MDD and healthy controls (HC) to evaluate whether these groups showed distinct features in FNC.
Methods: We collected resting‐state functional magnetic resonance imaging (fMRI) data from 20 BD patients, 15 patients with recurrent MDD as well as 30 age‐ and gender‐matched HC. Graph theoretical analyses were then applied to investigate functional brain networks on a global and regional network level.
Results: Global network analysis revealed a significantly higher mean global clustering coefficient in BD compared to HC. We further detected frontal, temporal and subcortical nodes in emotion regulation areas such as the limbic system and associated regions exhibiting significant differences in network integration and segregation in BD compared to MDD patients and HC. Participants with MDD and HC only differed in frontal and insular network centrality.
Conclusion: In conclusion, our findings indicate that a significantly altered brain network topology in the limbic system might be a trait marker specific to BD. Brain network analysis in these regions may therefore be used to differentiate euthymic BD not only from HC but also from patients with MDD.
Most current models assume that the perceptual and cognitive processes of visual word recognition and reading operate upon neuronally coded domain-general low-level visual representations – typically oriented line representations. We here demonstrate, consistent with neurophysiological theories of Bayesian-like predictive neural computations, that prior visual knowledge of words may be utilized to ‘explain away’ redundant and highly expected parts of the visual percept. Subsequent processing stages, accordingly, operate upon an optimized representation of the visual input, the orthographic prediction error, highlighting only the visual information relevant for word identification. We show that this optimized representation is related to orthographic word characteristics, accounts for word recognition behavior, and is processed early in the visual processing stream, i.e., in V4 and before 200 ms after word-onset. Based on these findings, we propose that prior visual-orthographic knowledge is used to optimize the representation of visually presented words, which in turn allows for highly efficient reading processes.
Introduction: The neurobiological mechanisms behind panic disorder with agoraphobia (PD/AG) are not completely explored. The functional A/T single nucleotide polymorphism (SNP) rs324981 in the neuropeptide S receptor gene (NPSR1) has repeatedly been associated with panic disorder and might partly drive function respectively dysfunction of the neural “fear network”. We aimed to investigate whether the NPSR1 T risk allele was associated with malfunctioning in a fronto-limbic network during the anticipation and perception of agoraphobia-specific stimuli.
Method: 121 patients with PD/AG and 77 healthy controls (HC) underwent functional magnetic resonance imaging (fMRI) using the disorder specific “Westphal-Paradigm”. It consists of neutral and agoraphobia-specific pictures, half of the pictures were cued to induce anticipatory anxiety.
Results: Risk allele carriers showed significantly higher amygdala activation during the perception of agoraphobia-specific stimuli than A/A homozygotes. A linear group x genotype interaction during the perception of agoraphobia-specific stimuli showed a strong trend towards significance. Patients with the one or two T alleles displayed the highest and HC with the A/A genotype the lowest activation in the inferior orbitofrontal cortex (iOFC).
Discussion: The study demonstrates an association of the NPSR1rs324981 genotype and the perception of agoraphobia-specific stimuli. These results support the assumption of a fronto-limbic dysfunction as an intermediate phenotype of PD/AG.
Rationale: Both attention deficit-/hyperactivity disorder (ADHD) and alcohol use disorder (AUD) are accompanied by deficits in response inhibition. Furthermore, the prevalence of comorbidity of ADHD and AUD is high. However, there is a lack of research on whether the same neuronal subprocesses of inhibition (i.e., interference inhibition, action withholding and action cancellation) exhibit deficits in both psychiatric disorders. Methods: We examined these three neural subprocesses of response inhibition in patient groups and healthy controls: non-medicated individuals with ADHD (ADHD; N = 16), recently detoxified and abstinent individuals with alcohol use disorder (AUD; N = 15), and healthy controls (HC; N = 15). A hybrid response inhibition task covering interference inhibition, action withholding, and action cancellation was applied using a 3T functional magnetic resonance imaging (fMRI). Results: Individuals with ADHD showed an overall stronger hypoactivation in attention related brain areas compared to AUD or HC during action withholding. Further, this hypoactivation was more accentuated during action cancellation. Individuals with AUD recruited a broader network, including the striatum, compared to HC during action withholding. During action cancellation, however, they showed hypoactivation in motor regions. Additionally, specific neural activation profiles regarding group and subprocess became apparent. Conclusions: Even though deficits in response inhibition are related to both ADHD and AUD, neural activation and recruited networks during response inhibition differ regarding both neuronal subprocesses and examined groups. While a replication of this study is needed in a larger sample, the results suggest that tasks have to be carefully selected when examining neural activation patterns of response inhibition either in research on various psychiatric disorders or transdiagnostic questions.
Understanding the underlying mechanisms that link psychopathology and physical comorbidities in schizophrenia is crucial since decreased physical fitness and overweight pose major risk factors for cardio-vascular diseases and decrease the patients’ life expectancies. We hypothesize that altered reward anticipation plays an important role in this. We implemented the Monetary Incentive Delay task in a MR scanner and a fitness test battery to compare schizophrenia patients (SZ, n = 43) with sex- and age-matched healthy controls (HC, n = 36) as to reward processing and their physical fitness. We found differences in reward anticipation between SZs and HCs, whereby increased activity in HCs positively correlated with overall physical condition and negatively correlated with psychopathology. On the other handy, SZs revealed stronger activity in the posterior cingulate cortex and in cerebellar regions during reward anticipation, which could be linked to decreased overall physical fitness. These findings demonstrate that a dysregulated reward system is not only responsible for the symptomatology of schizophrenia, but might also be involved in physical comorbidities which could pave the way for future lifestyle therapy interventions.
Early maternal care may counteract familial liability for psychopathology in the reward circuitry
(2018)
Reward processing is altered in various psychopathologies and has been shown to be susceptible to genetic and environmental influences. Here, we examined whether maternal care may buffer familial risk for psychiatric disorders in terms of reward processing. Functional magnetic resonance imaging during a monetary incentive delay task was acquired in participants of an epidemiological cohort study followed since birth (N = 172, 25 years). Early maternal stimulation was assessed during a standardized nursing/playing setting at the age of 3 months. Parental psychiatric disorders (familial risk) during childhood and the participants’ previous psychopathology were assessed by diagnostic interview. With high familial risk, higher maternal stimulation was related to increasing activation in the caudate head, the supplementary motor area, the cingulum and the middle frontal gyrus during reward anticipation, with the opposite pattern found in individuals with no familial risk. In contrast, higher maternal stimulation was associated with decreasing caudate head activity during reward delivery and reduced levels of attention deficit hyperactivity disorder (ADHD) in the high-risk group. Decreased caudate head activity during reward anticipation and increased activity during delivery were linked to ADHD. These findings provide evidence of a long-term association of early maternal stimulation on both adult neurobiological systems of reward underlying externalizing behavior and ADHD during development.
The comparison of persons is pervasive in social judgement and human decision making and yet its neural substrate is poorly explored. Using functional magnetic resonance imaging we investigated the brain activities of participants comparing other persons with each other (other vs. other comparison - OOC) and with themselves (self vs. other comparison - SOC) as regards psychological (intelligence) and physical (height) characteristics. We found that the comparison of these two person characteristics differ in their neural activation patterns in the OOC as well as in the SOC with higher activity increases for intelligence than height comparison in several areas in medial frontal and orbitofrontal cortex and posterior cingulate cortex suggesting that their activation scales with the demand on person comparison. The person comparison network strikingly overlaps the one commonly described for the classic theory of mind tasks. We interpret this overlap as indicating perspective taking common to person comparison and theory of mind. Furthermore, we suggest that the neural differences between the SOC and the OOC especially in the dorsal part of the medial frontal cortex rely on the different degree of the self involved in the two types of comparisons. The results additionally suggest that the decision directions of self-relevant comparisons, especially in the intelligence comparison of the SOC, resulted in differences in the activation of the medial frontal cortex, which also relies on differences in the reward anticipation and self-relatedness of these decisions.
Ten years ago, neuroscientists began to study cultural phenomena by using functional MRI. Since then the number of publications in this field, termed cultural neuroscience (CN), has tremendously increased. In these studies, particular concepts of culture are implied, but rarely explicitly discussed. We argue that it is necessary to make these concepts a topic of debate in order to unravel the foundations of CN. From 40 fMRI studies we extracted two strands of reasoning: models investigating universal mechanisms for the formation of cultural groups and habits and, models assessing differences in characteristics among cultural groups. Both strands simplify culture as an inflexible set of traits and specificities. We question this rigid understanding of culture and highlight its hidden evaluative nature.
We examined the neural signatures of stimulus features in visual working memory (WM) by integrating functional magnetic resonance imaging (fMRI) and event-related potential data recorded during mental manipulation of colors, rotation angles, and color–angle conjunctions. The N200, negative slow wave, and P3b were modulated by the information content of WM, and an fMRI-constrained source model revealed a progression in neural activity from posterior visual areas to higher order areas in the ventral and dorsal processing streams. Color processing was associated with activity in inferior frontal gyrus during encoding and retrieval, whereas angle processing involved right parietal regions during the delay interval. WM for color–angle conjunctions did not involve any additional neural processes. The finding that different patterns of brain activity underlie WM for color and spatial information is consistent with ideas that the ventral/dorsal “what/where” segregation of perceptual processing influences WM organization. The absence of characteristic signatures of conjunction-related brain activity, which was generally intermediate between the 2 single conditions, suggests that conjunction judgments are based on the coordinated activity of these 2 streams. Keywords: EEG, fMRI, source analysis, visual, working memory
Pattern recognition approaches, such as the Support Vector Machine (SVM), have been successfully used to classify groups of individuals based on their patterns of brain activity or structure. However these approaches focus on finding group differences and are not applicable to situations where one is interested in accessing deviations from a specific class or population. In the present work we propose an application of the one-class SVM (OC-SVM) to investigate if patterns of fMRI response to sad facial expressions in depressed patients would be classified as outliers in relation to patterns of healthy control subjects. We defined features based on whole brain voxels and anatomical regions. In both cases we found a significant correlation between the OC-SVM predictions and the patients' Hamilton Rating Scale for Depression (HRSD), i.e. the more depressed the patients were the more of an outlier they were. In addition the OC-SVM split the patient groups into two subgroups whose membership was associated with future response to treatment. When applied to region-based features the OC-SVM classified 52% of patients as outliers. However among the patients classified as outliers 70% did not respond to treatment and among those classified as non-outliers 89% responded to treatment. In addition 89% of the healthy controls were classified as non-outliers.
From age 5 to 7, there are remarkable improvements in children’s cognitive abilities (“5–7 shift”). In many countries, including Germany, formal schooling begins in this age range. It is, thus, unclear to what extent exposure to formal schooling contributes to the “5–7 shift.” In this longitudinal study, we investigated if schooling acts as a catalyst of maturation. We tested 5-year-old children who were born close to the official cutoff date for school entry and who were still attending a play-oriented kindergarten. One year later, the children were tested again. Some of the children had experienced their first year of schooling whereas the others had remained in kindergarten. Using 2 functional magnetic resonance imaging tasks that assessed episodic memory formation (i.e., subsequent memory effect), we found that children relied strongly on the medial temporal lobe (MTL) at both time points but not on the prefrontal cortex (PFC). In contrast, older children and adults typically show subsequent memory effects in both MTL and PFC. Both children groups improved in their memory performance, but there were no longitudinal changes nor group differences in neural activation. We conclude that successful memory formation in this age group relies more heavily on the MTL than in older age groups.
Memory impairments are a major characteristic of schizophrenia (SZ). In the current study, we used an associative memory task to test the hypothesis that SZ patients and first-degree relatives have altered functional patterns in comparison to healthy controls. We analyzed the fMRI activation pattern during the presentation of a face-name task in 27 SZ patients, 23 first-degree relatives, and 27 healthy controls. In addition, we performed correlation analyses between individual psychopathology, accuracy and reaction time of the task and the beta scores of the functional brain activations. We observed a lower response accuracy and increased reaction time during the retrieval of face-name pairs in SZ patients compared with controls. Deficient performance was accompanied by abnormal functional activation patterns predominantly in DMN regions during encoding and retrieval. No significant correlation between individual psychopathology and neuronal activation during encoding or retrieval of face-name pairs was observed. Findings of first-degree relatives indicated slightly different functional pattern within brain networks in contrast to controls without significant differences in the behavioral task. Both the accuracy of memory performance as well as the functional activation pattern during retrieval revealed alterations in SZ patients, and, to a lesser degree, in relatives. The results are of potential relevance for integration within a comprehensive model of memory function in SZ. The development of a neurophysiological model of cognition in psychosis may help to clarify and improve therapeutic options to improve memory and functioning in the illness.
Emotional instability, difficulties in social adjustment, and disinhibited behavior are the most common symptoms of the psychiatric comorbidities in juvenile myoclonic epilepsy (JME). This psychopathology has been associated with dysfunctions of mesial-frontal brain circuits. The present work is a first direct test of this link and adapted a paradigm for probing frontal circuits during empathy for pain. Neural and psychophysiological parameters of pain empathy were assessed by combining functional magnetic resonance imaging (fMRI) with simultaneous pupillometry in 15 JME patients and 15 matched healthy controls. In JME patients, we observed reduced neural activation of the anterior cingulate cortex (ACC), the anterior insula (AI), and the ventrolateral prefrontal cortex (VLPFC). This modulation was paralleled by reduced pupil dilation during empathy for pain in patients. At the same time, pupil dilation was positively related to neural activity of the ACC, AI, and VLPFC. In JME patients, the ACC additionally showed reduced functional connectivity with the primary and secondary somatosensory cortex, areas fundamentally implicated in processing the somatic cause of another's pain. Our results provide first evidence that alterations of mesial-frontal circuits directly affect psychosocial functioning in JME patients and draw a link of pupil dynamics with brain activity during emotional processing. The findings of reduced pain empathy related activation of the ACC and AI and aberrant functional integration of the ACC with somatosensory cortex areas provide further evidence for this network's role in social behavior and helps explaining the JME psychopathology and patients' difficulties in social adjustment.
Talking about emotion and sharing emotional experiences is a key component of human interaction. Specifically, individuals often consider the reactions of other people when evaluating the meaning and impact of an emotional stimulus. It has not yet been investigated, however, how emotional arousal ratings and physiological responses elicited by affective stimuli are influenced by the rating of an interaction partner. In the present study, pairs of participants were asked to rate and communicate the degree of their emotional arousal while viewing affective pictures. Strikingly, participants adjusted their arousal ratings to match up with their interaction partner. In anticipation of the affective picture, the interaction partner’s arousal ratings correlated positively with activity in anterior insula and prefrontal cortex. During picture presentation, social influence was reflected in the ventral striatum, that is, activity in the ventral striatum correlated negatively with the interaction partner’s ratings. Results of the study show that emotional alignment through the influence of another person’s communicated experience has to be considered as a complex phenomenon integrating different components including emotion anticipation and conformity.
The visual system encompasses about 20% of the cerebral cortex1 and plays a pivotal role in higher-order cognitive processes such as attention and working memory. Cognitive impairments constitute a central role in neuropsychiatric disorders such as schizophrenia (SZ). Impairments are described in visual perceptual processes including contrast, and emotion discrimination as well as in the ability to identify visual irregularities and in higher-order cognition like visual attention and working memory. Furthermore, perceptual and higher-order cognitive processes are part of the Research Domain Criteria (RDoC) project that aims to develop dimensional and transdiagnostic constructs with defined links to specific brain circuits.Therefore, the detailed study of the visual system using functional magnetic resonance imaging (fMRI) is essential to understand the processes in healthy individuals but also in populations with neuropsychiatric disorders. Visual mapping techniques include functional localizer tasks to map functionally defined regions like the fusiform face area (FFA), retinotopic mapping to map specific brain regions that are retinotopically organized in full, and visual-field localizer paradigms to define circumscribed areas within retinotopically organized areas.Thus, the latter allow studying local information processing in early visual areas. Despite advances in neuroimaging techniques, analyses of fMRI data at the group-level are impeded by interindividual macroanatomical variability. This reduces the reliability to accurately define visual areas particularly at the group-level and decreases statistical power. Single-subject based solutions for this problem are not appropriate. Analyses after volume-based alignment (VBA) and primary surface-based analyses without macroanatomical alignment do not increase macroanatomical correspondence sufficiently. Cortex-based alignment (CBA) approaches are recommended as an alternative technique to address this obstacle. However, CBA has not been evaluated for visual-field localizer paradigms. Therefore, we aimed to evaluate potential benefits of CBA for an attention-enhanced visual field localizer paradigm that maps circumscribed regions in retinotopically organized visual areas. Since previous studies solely compared surface-based data before and after CBA, we aimed to compare all three techniques: (1) a volume-based alignment (VBA), (2) a surface-based data set without (SBAV) and (3) a surface- based data set with macroanatomical alignment (CBA). Furthermore, we sought to define regions of interest (ROI) that subsequently can be used for the study of higher-order cognitive processes. Also, we aimed to investigate whether CBA facilitates the study of functional asymmetries in early visual areas as these were described in previous studies. Healthy volunteers (n=50) underwent fMRI in a 3- Tesla Siemens Trio scanner while performing an attention-enhanced visual field localizer paradigm. Our task consisted of a series of flickering, black-and white colored checkerboard stimuli that randomly appeared at one of four locations comprising the participants’ visual quadrants. In 25% of the trials the centrally located squares briefly changed their color to yellow (target trial). Participants had to indicate detection of a target by button press. Data analysis was conducted using Brain Voyager 20.6. Our approach for macroanatomical alignment included a high-resolution, multiscale curvature driven alignment procedure minimizing interindividual macroanatomical variability. Here, each folding pattern was aligned to a dynamically updated group average. Thus, we counteracted a possible confounding effect of a suboptimal selection of an individual target brain with a folding pattern deviating considerably from the cohort average. Group ROIs after CBA showed increased spatial consistency, vertical symmetry, and an increase of size. This was corroborated by an increase in the probability of activation overlap of up to 86%. CBA increased macroanatomical correspondence and thus ameliorated results of multi-subject ROI analyses. Functional differences in the form of a downward bias in visual hemifields were measured with increased reliability. In summary, our findings provide clear evidence for the superiority of CBA for the study of local information processing in early visual cortex at the group-level. This approach is of relevance for the study of visual dysfunction in neuropsychiatric disorders including schizophrenia as they show impaired visual processing that in turn impacts higher-order cognitive processes and in consequence functional outcome. In addition, our attention-enhanced visual field localizer paradigm will be useful for machine learning approaches such as multivariate pattern analysis decoding local information processes and connectivity patterns.
Background: Conduct disorder (CD), which is characterized by severe aggressive and antisocial behavior, is linked to emotion processing and regulation deficits. However, the neural correlates of emotion regulation are yet to be investigated in adolescents with CD. Furthermore, it remains unclear whether CD is associated with deficits in emotional reactivity, emotion regulation, or both.
Methods: We used functional magnetic resonance imaging to study effortful emotion regulation by cognitive reappraisal in 59 female adolescents 15 to 18 years of age (30 with a CD diagnosis and 29 typically developing (TD) control adolescents).
Results: Behaviorally, in-scanner self-report ratings confirmed successful emotion regulation within each group individually but significant group differences in emotional reactivity and reappraisal success when comparing the groups (CD < TD). Functional magnetic resonance imaging results revealed significantly lower activation in left dorsolateral prefrontal cortex and angular gyrus in CD compared with TD adolescents during emotion regulation, but no group differences for emotional reactivity. Furthermore, connectivity between left dorsolateral prefrontal cortex and the bilateral putamen, right prefrontal cortex, and amygdala was reduced in CD compared with TD adolescents during reappraisal. Callous-unemotional traits were unrelated to neural activation, but these traits correlated negatively with behavioral reports of emotional reactivity.
Conclusions: Our results demonstrate reduced prefrontal brain activity and functional connectivity during effortful emotion regulation in female adolescents with CD. This sheds light on the neural basis of the behavioral deficits that have been reported previously. Future studies should investigate whether cognitive interventions are effective in enhancing emotion-regulation abilities and/or normalizing prefrontal and temporoparietal activity in female adolescents with CD.
Pattern recognition applied to whole-brain neuroimaging data, such as functional Magnetic Resonance Imaging (fMRI), has proved successful at discriminating psychiatric patients from healthy participants. However, predictive patterns obtained from whole-brain voxel-based features are difficult to interpret in terms of the underlying neurobiology. Many psychiatric disorders, such as depression and schizophrenia, are thought to be brain connectivity disorders. Therefore, pattern recognition based on network models might provide deeper insights and potentially more powerful predictions than whole-brain voxel-based approaches. Here, we build a novel sparse network-based discriminative modeling framework, based on Gaussian graphical models and L1-norm regularized linear Support Vector Machines (SVM). In addition, the proposed framework is optimized in terms of both predictive power and reproducibility/stability of the patterns. Our approach aims to provide better pattern interpretation than voxel-based whole-brain approaches by yielding stable brain connectivity patterns that underlie discriminative changes in brain function between the groups. We illustrate our technique by classifying patients with major depressive disorder (MDD) and healthy participants, in two (event- and block-related) fMRI datasets acquired while participants performed a gender discrimination and emotional task, respectively, during the visualization of emotional valent faces.
Motives motivate human behavior. Most behaviors are driven by more than one motive, yet it is unclear how different motives interact and how such motive combinations affect the neural computation of the behaviors they drive. To answer this question, we induced two prosocial motives simultaneously (multi-motive condition) and separately (single motive conditions). After the different motive inductions, participants performed the same choice task in which they allocated points in favor of the other person (prosocial choice) or in favor of themselves (egoistic choice). We used fMRI to assess prosocial choice-related brain responses and drift diffusion modeling to specify how motive combinations affect individual components of the choice process. Our results showed that the combination of the two motives in the multi-motive condition increased participants’ choice biases prior to the behavior itself. On the neural level, these changes in initial prosocial bias were associated with neural responses in the bilateral dorsal striatum. In contrast, the efficiency of the prosocial decision process was comparable between the multi-motive and the single-motive conditions. These findings provide insights into the computation of prosocial choices in complex motivational states, the motivational setting that drives most human behaviors.
The neural processing of speech and music is still a matter of debate. A long tradition that assumes shared processing capacities for the two domains contrasts with views that assume domain-specific processing. We here contribute to this topic by investigating, in a functional magnetic imaging (fMRI) study, ecologically valid stimuli that are identical in wording and differ only in that one group is typically spoken (or silently read), whereas the other is sung: poems and their respective musical settings. We focus on the melodic properties of spoken poems and their sung musical counterparts by looking at proportions of significant autocorrelations (PSA) based on pitch values extracted from their recordings. Following earlier studies, we assumed a bias of poem-processing towards the left and a bias for song-processing on the right hemisphere. Furthermore, PSA values of poems and songs were expected to explain variance in left- vs. right-temporal brain areas, while continuous liking ratings obtained in the scanner should modulate activity in the reward network. Overall, poem processing compared to song processing relied on left temporal regions, including the superior temporal gyrus, whereas song processing compared to poem processing recruited more right temporal areas, including Heschl's gyrus and the superior temporal gyrus. PSA values co-varied with activation in bilateral temporal regions for poems, and in right-dominant fronto-temporal regions for songs. Continuous liking ratings were correlated with activity in the default mode network for both poems and songs. The pattern of results suggests that the neural processing of poems and their musical settings is based on their melodic properties, supported by bilateral temporal auditory areas and an additional right fronto-temporal network known to be implicated in the processing of melodies in songs. These findings take a middle ground in providing evidence for specific processing circuits for speech and music in the left and right hemisphere, but simultaneously for shared processing of melodic aspects of both poems and their musical settings in the right temporal cortex. Thus, we demonstrate the neurobiological plausibility of assuming the importance of melodic properties in spoken and sung aesthetic language alike, along with the involvement of the default mode network in the aesthetic appreciation of these properties.
In human neuroscientific research, there has been an increasing interest in how the brain computes the value of an anticipated outcome. However, evidence is still missing about which valuation related brain regions are modulated by the proximity to an expected goal and the previously invested effort to reach a goal. The aim of this dissertation is to investigate the effects of goal proximity and invested effort on valuation related regions in the human brain. We addressed this question in two fMRI studies by integrating a commonly used reward anticipation task in differential versions of a Multitrial Reward Schedule Paradigm. In both experiments, subjects had to perform consecutive reward anticipation tasks under two different reward contingencies: in the delayed condition, participants received a monetary reward only after successful completion of multiple consecutive trials. In the immediate condition, money was earned after every successful trial. In the first study, we could demonstrate that the rostral cingulate zone of the posterior medial frontal cortex signals action value contingent to goal proximity, thereby replicating neurophysiological findings about goal proximity signals in a homologous region in non-human primates. The findings of the second study imply that brain regions associated with general cognitive control processes are modulated by previous effort investment. Furthermore, we found the posterior lateral prefrontal cortex and the orbitofrontal cortex to be involved in coding for the effort-based context of a situation. In sum, these results extend the role of the human rostral cingulate zone in outcome evaluation to the continuous updating of action values over a course of action steps based on the proximity to the expected reward. Furthermore, we tentatively suggest that previous effort investment invokes processes under the control of the executive system, and that posterior lateral prefrontal cortex and the orbitofrontal cortex are involved in an effort-based context representation that can be used for outcome evaluation that is dependent on the characteristics of the current situation.
In recent years, a number of functional and structural neuroimaging studies have investigated the neural bases of aggressive and violent behaviour in children and adolescents. Most functional neuroimaging studies have persued the hypothesis that pathological aggression is a consequence of deficits in the neural circuits involved in emotion processing. There is converging evidence for abnormal neural responses to emotional stimuli in youths with a propensity towards aggressive behaviour. In addition, recent neuroimaging work has suggested that aggressive behaviour is also associated with abnormalities in neural processes that subserve both the inhibitory control of behaviour and the flexible adaptation of behaviour in accord with reinforcement information. Structural neuroimaging studies in children and adolescents with conduct problems are still scarce, but point to deficits in brain structures involved in the processing of social information and in the regulation of social and goal-directed behaviour. The indisputable progress that this research field has made in recent years notwithstanding, the overall picture is still rather patchy and there are inconsistencies between studies that await clarification. Despite this, we attempt to provide an integrated view on the neural abnormalities that may contribute to various forms of juvenile aggression and violence, and discuss research strategies that may help to provide a more profound understanding of these important issues in the future. Keywords: aggression, violence, conduct disorder, fMRI, brain imaging, psychiatry
Human deep sleep is characterized by reduced sensory activity, responsiveness to stimuli, and conscious awareness. Given its ubiquity and reversible nature, it represents an attractive paradigm to study the neural changes which accompany the loss of consciousness in humans. In particular, the deepest stages of sleep can serve as an empirical test for the predictions of theoretical models relating the phenomenology of consciousness with underlying neural activity. A relatively recent shift of attention from the analysis of evoked responses toward spontaneous (or “resting state”) activity has taken place in the neuroimaging community, together with the development of tools suitable to study distributed functional interactions. In this review we focus on recent functional Magnetic Resonance Imaging (fMRI) studies of spontaneous activity during sleep and their relationship with theoretical models for human consciousness generation, considering the global workspace theory, the information integration theory, and the dynamical core hypothesis. We discuss the venues of research opened by these results, emphasizing the need to extend the analytic methodology in order to obtain a dynamical picture of how functional interactions change over time and how their evolution is modulated during different conscious states. Finally, we discuss the need to experimentally establish absent or reduced conscious content, even when studying the deepest sleep stages.