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ABSTRACT: Research has linked oscillatory activity in the α frequency range, particularly in sensorimotor cortex, to processing of social actions. Results further suggest involvement of sensorimotor α in the processing of facial expressions, including affect. The sensorimotor face area may be critical for perception of emotional face expression, but the role it plays is unclear. The present study sought to clarify how oscillatory brain activity contributes to or reflects processing of facial affect during changes in facial expression. Neuromagnetic oscillatory brain activity was monitored while 30 volunteers viewed videos of human faces that changed their expression from neutral to fearful, neutral, or happy expressions. Induced changes in α power during the different morphs, source analysis, and graph-theoretic metrics served to identify the role of α power modulation and cross-regional coupling by means of phase synchrony during facial affect recognition. Changes from neutral to emotional faces were associated with a 10-15 Hz power increase localized in bilateral sensorimotor areas, together with occipital power decrease, preceding reported emotional expression recognition. Graph-theoretic analysis revealed that, in the course of a trial, the balance between sensorimotor power increase and decrease was associated with decreased and increased transregional connectedness as measured by node degree. Results suggest that modulations in α power facilitate early registration, with sensorimotor cortex including the sensorimotor face area largely functionally decoupled and thereby protected from additional, disruptive input and that subsequent α power decrease together with increased connectedness of sensorimotor areas facilitates successful facial affect recognition.
Journal of Neuroscience 04/2013; 33(14):6018-26. · 7.11 Impact Factor
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ABSTRACT: Hemodynamic and electromagnetic neuroimaging suggests a sequence of intraregional and interregional activity during emotion processing. Oscillatory activity within trials may offer insight into neural mechanisms involved in this process. MEG was measured in 24 subjects during passive viewing of neutral and unpleasant pictures and emotion regulation by cognitive reappraisal. Regulation prompted more gamma increase and alpha decrease to picture onset than did passive viewing. Source analysis confirmed differential modulation of these power changes in occipitoparietal regions during passive viewing and larger power changes in prefrontal regions during regulation. Local coupling of alpha phase to gamma amplitude within a medial prefrontal region and long-range synchrony of medial prefrontal, occipital, and temporoparietal regions index mechanisms of prefrontal top-down contribution to emotion processing.
Psychophysiology 02/2013; · 3.29 Impact Factor
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ABSTRACT: Endophenotypes for psychopathology have been conceived as latent, unobserved, but measureable manifestations of phenomena that causally connect genetic liability to clinical disorder. Several decades of research have led to refinement of the construct and identification of some candidate endophenotypes, but rather limited progress on finding the genes involved or the mechanisms by which endophenotypes are driven by genetic and environmental factors and in turn drive psychopathology. Currently promising avenues for research involve development of transdiagnostic concepts not limited to traditional diagnostic categories, measures of endophenotypic and manifest psychopathology that have higher validity than those categories, and methods for modeling complex relationships among diverse contributors to etiology. With more grounding in animal neuroscience and other aspects of basic biological and psychological science, exemplified in the Research Domain Criteria initiative, there is every reason to anticipate that the endophenotype concept will grow more central in the psychopathology literature. Expected final online publication date for the Annual Review of Clinical Psychology Volume 9 is March 26, 2013. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.
Annual Review of Clinical Psychology 01/2013; · 9.11 Impact Factor
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ABSTRACT: Substantial evidence documented that adverse childhood experiences exert deleterious effects on mental health. It is less clear, to what extent specific maltreatment during specific developmental periods vary between disorders rather than raising vulnerability for any suffering. The present comparison of characteristics of childhood adversity (type and frequency of adversity, developmental period) between Major Depressive Disorder (MDD), Borderline Personality Disorder (BPD), schizophrenia, and psychiatrically healthy subjects examined how effects of adverse childhood experiences vary between disorders. Patients generally reported more adversities than healthy subjects. Irrespective of diagnosis, emotional maltreatment was substantial in all patients. BPD was characterized by marked increase of adversities across age relative to MDD and schizophrenia. Fifty-six percent of BPD, 40% MDD and 18% of schizophrenia sample experienced significant degree of early adversities. Stress pattern (type and time) varied between diagnoses, but not for patients with significant early adversities. Regression analyses confirmed early experiences as predictor of BPD, but not MDD and schizophrenia. Prepubescent experiences predicted affective and traumatic symptoms in BPD, and moderated the association with symptoms in MDD. Results indicate a dose-effect with differential impact of adverse childhood experiences in BPD, MDD, and schizophrenia, while early maltreatment beyond a certain degree affects mental health independent of diagnosis.
Psychiatry research. 12/2012;
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ABSTRACT: Traumatic stressors such as water boarding, electric shock, or false execution all activate similar bodily, affective, and cognitive responses even when they are quite different from one another. As a result, the memory traces merge into a “trauma network” that includes sensory memories but becomes detached from the particular episodic memory; that is, the trauma network has no time or place. As, with increasing traumatic experiences, more and more cues become integrated in the network, the threshold for excitation is continually lowered and the individual is likely to show frequent alarm and other defense responses to reminders of the trauma. Neuroplastic mechanisms determine subsequent reorganization of brain circuitry in order to adapt to a presumed permanent need for defense. We hypothesized that aversive pictorial material is differentially processed in visual as well as frontal and limbic areas of the traumatized brain. We used Rapid Serial Visual Presentation (three pictures per second) to present aversive, neutral, and appetitive pictorial stimuli. Event-related magnetic fields were recorded in 41 survivors of torture and organized violence who suffered from posttraumatic stress disorder (PTSD) as well as 43 controls with a comparable ethnic background. Traumatized individuals showed an early shift in the processing of aversive pictures from sensory visual areas to fronto-temporal areas and the amygdala compared to controls without trauma-related symptoms. For survivors, as opposed to controls, these stimuli automatically activate aspects of the defense cascade and thus lead to an excitation of action-related neural activity. We conclude that an enlarged fear network in survivors of organized violence has a low excitation threshold, thus leading to prominent PTSD symptoms. A disintegration of the fear network by reconnecting its elements to the respective episodic memory or by some form of inhibition of the network may bring relief. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Zeitschrift für Psychologie 10/2012; 219(3):167-174. · 1.57 Impact Factor
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ABSTRACT: Dysfunctional emotion regulation is often reported in affective disorders, but it is unclear whether this dysfunction concerns initial processing of emotional input or regulation of resulting emotion. The present study addressed these aspects in 27 depressive and 15 borderline personality disorder patients and 28 healthy controls who were instructed to either passively view unpleasant and neutral pictures or downregulate emotional responses by reappraisal, while neuromagnetic brain activity was measured. All three groups showed more early response to unpleasant than to neutral pictures, whereas patients failed to show subsequent activity suppression under instructions to down-regulate. This deficient emotion regulation was evident primarily in those subjects reporting high childhood adversity. Results support intact emotional input processing but impaired emotion regulation in affective disorders and indicate a moderating influence of early life stress.
Depression research and treatment 01/2012; 2012:156529.
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ABSTRACT: In a previous report we showed that cognitive training fostering auditory-verbal discrimination and working memory normalized magnetoencephalographic (MEG) M50 gating ratio in schizophrenia patients. The present analysis addressed whether training effects on M50 ratio and task performance are mediated by changes in brain oscillatory activity. Such evidence should improve understanding of the role of oscillatory activity in phenomena such as M50 ratio, the role of dysfunctional oscillatory activity in processing abnormalities in schizophrenia, and mechanisms of action of cognitive training.
Time-locked and non-time-locked oscillatory activity was measured together with M50 ratio in a paired-click design before and after a 4-week training of 36 patients randomly assigned to specific cognitive exercises (CE) or standard (comparison) cognitive training (CP). Patient data were compared to those of 15 healthy controls who participated in two MEG measurements 4 weeks apart without training. Training led to more time-locked gamma-band response and more non-time-locked alpha-band desynchronization, moreso after CE than after CP. Only after CE, increased alpha desynchronization was associated with normalized M50 ratio and with improved verbal memory performance. Thus, both types of cognitive training normalized gamma activity, associated with improved stimulus encoding. More targeted training of auditory-verbal discrimination and memory additionally normalized alpha desynchronization, associated with improved elaborative processing. The latter presumably contributes to improved auditory gating and cognitive function.
Results suggest that dysfunctional interplay of ocillatory activity that may contribute to auditory processing disruption in schizophrenia can be modified by targeted training.
PLoS ONE 01/2012; 7(7):e39051. · 4.09 Impact Factor
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ABSTRACT: Schizophrenia patients commonly exhibit smaller amplitudes of mismatch negativity (MMN) than in controls. It remains unclear whether this results from deficient processes indexed by MMN or 'normally' though more variable processing. The present magnetoencephalographic study addressed this question by analyzing intra-individual trial-by-trial variability and MMN amplitude.
Twenty inpatients meeting ICD criteria for schizophrenia and 18 healthy controls participated in an auditory oddball experiment. The neuromagnetic mismatch field (MMNm) was defined as the difference waveform deviant minus standard tone response. Variability index (VI) in different frequency bands was quantified as trial-by-trial variation of stimulus-evoked responses and epoch-by-epoch variation of signal amplitude during a resting condition.
Patients displayed a smaller MMNm amplitude and higher VI during the oddball experiment and during the resting condition than in controls. VI and MMNm amplitude were correlated in controls, but not in patients.
Reduced MMN in schizophrenia cannot be explained by augmented variability of brain activity; deficient auditory sensory memory and stimulus related phase-locking may characterize the disorder.
Understanding the contribution of diminished temporal stability of neuronal network dynamics to schizophrenia is crucial in modeling the impact of such instability on performance and thus for understanding deviant attention and memory functions.
Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 05/2011; 122(12):2365-74. · 3.12 Impact Factor
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ABSTRACT: The ratio of scalp-recorded brain responses occurring 50 msec after paired clicks (S2-evoked P50/S1-evoked P50) serves as a measure of sensory gating. An abnormally large ratio is commonly found in schizophrenia and is considered as a sign of reduced sensory gating or otherwise dysfunctional organization of the auditory/verbal system as a factor contributing to psychopathology and cognitive dysfunction in schizophrenia. This initial randomized clinical trial compared the efficacy of two 4-week, computer-based cognitive training methods that emphasize either auditory discrimination and verbal memory or a broader range of cognitive functions in schizophrenia.
Thirty-nine schizophrenia patients (ICD-F20.0 diagnosis) were assigned to Cognitive Exercises (CE) or Cognitive Package (Cogpack). The M50, the magnetoencephalographic analogue of electroencephalographic P50, and performance on verbal learning and memory tests were used to evaluate training effects.
As expected, patients exhibited higher pretreatment gating ratios than 28 age-matched healthy comparison participants. Gating ratios decreased after CE but not after Cogpack. Cognitive test performance improved more after CE than after Cogpack.
Appropriately specific psychological training changes the neural performance in schizophrenia, normalizing sensory and cognitive function.
Biological psychiatry 03/2011; 69(5):465-71. · 8.93 Impact Factor
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ABSTRACT: The ratio of magnetoencephalogram-recorded brain responses occurring 50ms after paired clicks (S2-evoked M50/S1-evoked M50) serves as a measure of sensory gating. An abnormally large ratio is commonly found in schizophrenia. Whether this abnormality indicates impaired gating is debated. Using event-related oscillations the present study sought to elucidate processes contributing to the phenomenon of altered M50 gating ratio. Schizophrenia inpatients (n=50) showed the expected large M50 gating ratio relative to 48 healthy controls, which correlated with less induced frontally generated activity in the 10-15Hz frequency band starting 200ms before the onset of S2. Patients also produced smaller alpha (8-12Hz) and gamma (60-80Hz) responses to S1. Results suggest that the deviant gating ratio in schizophrenia is a consequence of a complex alteration in the processing of incoming information that cannot be attributed to impaired gating alone.
NeuroImage 02/2011; 56(1):307-14. · 5.89 Impact Factor
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ABSTRACT: Distinct psychological processes have been proposed to unfold in decision-making. The time course of neural mechanisms supporting these processes has not been fully identified. The present MEG study examined spatio-temporal activity related to components of decision-making proposed to support reward valuation, reward prediction, and outcome evaluation. Each trial presented information on reward value (10 or 50 cents) and reward probability (10%, 50%, or 90%). Brain activity related to those inputs and to outcome feedback was evaluated via electromagnetic responses in source space. Distributed dipole activity reflected reward value and reward probability 150-350 ms after information arrival. Neural responses to reward-value information peaked earlier than those to reward-probability information. Results suggest that valuation, prediction, and outcome evaluation share neural structures and mechanisms even on a relatively fine time scale.
Psychophysiology 01/2011; 48(8):1037-46. · 3.29 Impact Factor
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ABSTRACT: Attention Deficit Hyperactivity Disorder (ADHD) is one of the most prevalent disorders in children and adolescence. Impulsivity is one of three core symptoms and likely associated with inhibition difficulties. To date the neural correlate of the antisaccade task, a test of response inhibition, has not been studied in children with (or without) ADHD.
Antisaccade responses to visual and acoustic cues were examined in nine unmedicated boys with ADHD (mean age 122.44 ± 20.81 months) and 14 healthy control children (mean age 115.64 ± 22.87 months, three girls) while an electroencephalogram (EEG) was recorded. Brain activity before saccade onset was reconstructed using a 23-source-montage.
When cues were acoustic, children with ADHD had a higher source activity than control children in Medio-Frontal Cortex (MFC) between -230 and -120 ms and in the left-hemispheric Temporal Anterior Cortex (TAC) between -112 and 0 ms before saccade onset, despite both groups performing similarly behaviourally (antisaccades errors and saccade latency). When visual cues were used EEG-activity preceding antisaccades did not differ between groups.
Children with ADHD exhibit altered functioning of the TAC and MFC during an antisaccade task elicited by acoustic cues. Children with ADHD need more source activation to reach the same behavioural level as control children.
BMC Psychiatry 01/2011; 11:7. · 2.55 Impact Factor
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ABSTRACT: Allocating electromagnetic auditory responses to active regions in the human auditory cortex can be difficult because of high interindividual variability of the relevant structures. Location and orientation of the primary auditory cortex (Heschl's Gyrus) and the temporal plane vary with individual features such as age, gender, handedness, or between healthy subjects and patients with a psychiatric disorder (e.g., schizophrenia). Here, we propose a reference coordinate system that considers the individual MRI-based position, orientation and length of the primary auditory cortex to account for interindividual variability. Transformation of the M50 dipole localizations in this new HG-(Heschl's-Gyrus)-coordinate system, accomplished for 10 healthy subjects and 10 schizophrenia patients, confirmed group difference more precisely than other registration methods. We suggest to use the HG-coordinate system for localization of functional measures and evaluation of brain activity differences between groups or measurement conditions.
Journal of neuroscience methods 09/2010; 192(1):121-6. · 2.30 Impact Factor
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ABSTRACT: Previous results suggest that early life stress (ELS) may be related to altered cortical responses to emotional stimuli. In a previous study, we found suppressed cortical responses to emotional pictures in psychiatric patients with high-ELS. The present study explored the stability of this effect across time and stimulation conditions. In addition, the relationship between ELS and current life stress was examined, and we probed whether this current life stress was related to the cortical responses. Fifteen patients with high, 16 patients with low-ELS and 15 psychiatrically healthy subjects with low-ELS participated in two sessions 8 months apart. Subjects monitored a rapid serial presentation of pleasant, neutral and unpleasant pictures during magnetoencephalographic recording. In both sessions, estimated neural activity in occipital-parietal-temporal regions between 70 and 250 ms after picture onset was smaller in patients, particularly in those with high-ELS, compared to healthy subjects. Modulation of activity by arousing (pleasant and unpleasant) compared to neutral stimuli around 200 ms post-stimulus did not differ between groups, whereas around 300 ms, patients did not show the pronounced cortical response to pleasant stimuli exhibited by healthy subjects. Results suggest that ELS and psychiatric disorder (1) diminish early perceptual processing (<200 ms) of emotional stimuli without substantially affecting activity modulation by stimulus arousal value, (2) diminish later attention allocation processes (>300 ms), and (3) are related to more recent life stress. High intraindividual correlations of activity patterns between sessions suggest lasting effects of ELS on processing modes.
International journal of psychophysiology: official journal of the International Organization of Psychophysiology 03/2010; 75(3):277-86. · 3.05 Impact Factor
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ABSTRACT: The concept of a 'fear network', i.e. an interconnected set of neural representations has been instrumental in explaining symptoms and their maintenance in anxiety disorders. The neural representations include both, response propositions such as flight or freezing and chunks of memory, conceptualized as Hebbian cell assemblies. Consequently, the fear network undergoes neuroplastic modifications, for instance, incremental enlargements with repeated exposure to threat and danger. This will in turn modify future processing of sensory stimuli and ultimately lead to an altered architecture of the brain's processing machinery and information processing modes. Using repeated exposure to traumatic stress as a model to study these processes, we summarize a series of magnetoencephalographic investigations from our laboratory, which demonstrate a characteristic pattern of early activation (before 100 ms latency to the eliciting stimulus) in fronto-cortical circuits by high-arousing, aversive pictorial and verbal stimuli in individuals presenting with posttraumatic stress disorder (PTSD). We propose that this pattern reflects a preference of stressed brains to engage a 'low road' sensory processing, which is fast but uncoupled from prefrontal regulatory control and which easily activates an alarm response, whereas less emphasis is given the more careful and contextual processing via the 'high road' along the ventral stream. As a result, the brain's architecture is changed from a careful analyzer of the environment to a rapid threat detector with a low threshold to engage in costly defense.
International journal of psychophysiology: official journal of the International Organization of Psychophysiology 02/2010; 78(1):14-9. · 3.05 Impact Factor
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ABSTRACT: Altered affective processing has been proposed as mediating between early life stress (ELS) and subsequent psychopathology. The present study examined whether ELS influences affective cortical processing differently in psychiatric patients and healthy subjects. The number of stressful experiences before onset of puberty was assessed in 50 inpatients with diagnoses of Major Depressive Disorder, schizophrenia, drug addiction, or Borderline Personality Disorder and in 20 healthy comparison subjects. Subjects monitored pleasant, neutral, and unpleasant pictures during magnetoencephalographic recording. Suppression of right-posterior activity 160-210 ms after stimulus onset was associated with certain diagnoses and high ELS. Results confirmed specific contributions of ELS versus adult stress, comorbid posttraumatic stress disorder, or depression.
Psychophysiology 09/2009; 46(6):1234-43. · 3.29 Impact Factor
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Social Science [?] Medicine 08/2009; · 2.70 Impact Factor
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ABSTRACT: As we age, our ability to select and to produce words changes, yet we know little about the underlying neural substrate of word-finding difficulties in old adults. This study was designed to elucidate changes in specific frontally mediated retrieval processes involved in word-finding difficulties associated with advanced age. We implemented two overt verbal (semantic and phonemic) fluency tasks during fMRI and compared brain activity patterns of old and young adults. Performance during the phonemic task was comparable for both age groups and mirrored by strongly left-lateralized (frontal) activity patterns. On the other hand, a significant drop of performance during the semantic task in the older group was accompanied by additional right (inferior and middle) frontal activity, which was negatively correlated with performance. Moreover, the younger group recruited different subportions of the left inferior frontal gyrus for both fluency tasks, whereas the older participants failed to show this distinction. Thus, functional integrity and efficient recruitment of left frontal language areas seems to be critical for successful word retrieval in old age.
Journal of Cognitive Neuroscience 04/2009; 21(10):2007-18. · 5.18 Impact Factor
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ABSTRACT: In the composition of an event the verb's argument structure defines the number of participants and their relationships. Previous studies indicated distinct brain responses depending on how many obligatory arguments a verb takes. The present functional magnetic resonance imaging (fMRI) study served to verify the neural structures involved in the processing of German verbs with one (e.g. "snore") or three (e.g. "gives") argument structure. Within a silent reading design, verbs were presented either in isolation or with a minimal syntactic context ("snore" vs. "Peter snores").
Reading of isolated one-argument verbs ("snore") produced stronger BOLD responses than three-argument verbs ("gives") in the inferior temporal fusiform gyrus (BA 37) of the left hemisphere, validating previous magnetoencephalographic findings. When presented in context one-argument verbs ("Peter snores") induced more pronounced activity in the inferior frontal gyrus (IFG) of the left hemisphere than three-argument verbs ("Peter gives").
In line with previous studies our results corroborate the left temporal lobe as site of representation and the IFG as site of processing of verbs' argument structure.
BMC Neuroscience 02/2009; 10:3. · 3.04 Impact Factor
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ABSTRACT: Self-regulation of intention formation is pivotal for achieving behavior change. Fantasy realization theory (Oettingen, 2000) assumes that mentally contrasting a desired positive future with present negative reality turns high expectations of success into strong intentions to realize the desired future, while indulging in the positive future fails to do so. The present study tests the theory's process assumption that mental contrasting is a cognitively demanding, purposeful problem-solving strategy involving working and episodic memory, whereas indulging is a mindless daydreaming strategy involving the free flow of thought, by investigating the neural correlates of the two strategies via continuous magnetoencephalographic (MEG) activity. We observed greater activity during mental contrasting (but not indulging) compared to resting in prefrontal, frontal, parietal, and temporal areas, indicating that mental contrasting involves strong intention formation, working memory, and episodic memory. In addition, heightened activity of occipital areas was observed during mental contrasting compared to resting and indulging, suggesting that mental contrasting, more than indulging and resting, entails purposefully creating mental images. Taken together, these findings indicate that mental contrasting is indeed a purposeful problem-solving strategy based on past performance history, whereas indulging is a purposeless daydreaming strategy that is oblivious to past experiences.
Social neuroscience 01/2009; 4(1):11-27. · 3.17 Impact Factor
