948 research outputs found

    Advanced nonlinear engine speed control systems

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    Higher Order Continuous SI Engine Observers

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    Transgenerational consequences of PTSD: risk factors for the mental health of children whose mothers have been exposed to the Rwandan genocide

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    Roth M, Neuner F, Elbert T. Transgenerational consequences of PTSD: risk factors for the mental health of children whose mothers have been exposed to the Rwandan genocide. International Journal of Mental Health Systems. 2014;8(1): 12.Background: Understanding how parental Posttraumatic Stress Disorder (PTSD) may or may not affect the development and mental health in the offspring is particularly important in conflict regions, where trauma-related illness is endemic. In Rwanda, organised atrocities and the genocide against the Tutsi of 1994 have left a significant fraction of the population with chronic PTSD. The aim of the present investigation was to establish whether PTSD in mothers is associated with symptoms of depression, anxiety, and aggressive and antisocial behaviour in their children. Methods: A community sample of 125 Rwandan mothers who experienced the genocide of 1994 and their 12-year-old children were interviewed. Using a structured interview, symptoms of maternal PTSD and children's depression, anxiety, and aggressive and antisocial behaviour were assessed by trained and on-site supervised local B. A. psychologists. The interview also included a detailed checklist of event types related to family violence. Results: In showing that a maternal PTSD was not associated with child's psychopathology, the results contradict the assumption of straight "trans-generational trauma transmission". Instead, a child's exposure to maternal family violence posed a significant risk factor for a negative mental health outcome. Furthermore, it was not maternal PTSD-symptoms but mother's exposure to family violence during her own childhood that was associated with the magnitude of adversities that a child experiences at home. Conclusions: Contrary to a simple model of a trans-generational transmission of trauma, neither maternal PTSD nor maternal traumatic experiences were directly associated with symptoms of anxiety, depression, or antisocial and aggressive behaviour in the children. Instead, the present results suggest a relationship between parental child rearing practices and children's mental health. Furthermore, the study details the "cycle of violence", showing a significant link between maternal violence against a child and its mother's experience of childhood maltreatment

    Attentional influences on functional mapping of speech sounds in human auditory cortex

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    BACKGROUND: The speech signal contains both information about phonological features such as place of articulation and non-phonological features such as speaker identity. These are different aspects of the 'what'-processing stream (speaker vs. speech content), and here we show that they can be further segregated as they may occur in parallel but within different neural substrates. Subjects listened to two different vowels, each spoken by two different speakers. During one block, they were asked to identify a given vowel irrespectively of the speaker (phonological categorization), while during the other block the speaker had to be identified irrespectively of the vowel (speaker categorization). Auditory evoked fields were recorded using 148-channel magnetoencephalography (MEG), and magnetic source imaging was obtained for 17 subjects. RESULTS: During phonological categorization, a vowel-dependent difference of N100m source location perpendicular to the main tonotopic gradient replicated previous findings. In speaker categorization, the relative mapping of vowels remained unchanged but sources were shifted towards more posterior and more superior locations. CONCLUSIONS: These results imply that the N100m reflects the extraction of abstract invariants from the speech signal. This part of the processing is accomplished in auditory areas anterior to AI, which are part of the auditory 'what' system. This network seems to include spatially separable modules for identifying the phonological information and for associating it with a particular speaker that are activated in synchrony but within different regions, suggesting that the 'what' processing can be more adequately modeled by a stream of parallel stages. The relative activation of the parallel processing stages can be modulated by attentional or task demands

    Focusing Light through Random Photonic Media by Binary Amplitude Modulation

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    We study the focusing of light through random photonic materials using wavefront shaping. We explore a novel approach namely binary amplitude modulation. To this end, the light incident to a random photonic medium is spatially divided into a number of segments. We identify the segments that give rise to fields that are out of phase with the total field at the intended focus and assign these a zero amplitude, whereas the remaining segments maintain their original amplitude. Using 812 independently controlled segments of light, we find the intensity at the target to be 75 +/- 6 times enhanced over the average intensity behind the sample. We experimentally demonstrate focusing of light through random photonic media using both an amplitude only mode liquid crystal spatial light modulator and a MEMS-based spatial light modulator. Our use of Micro Electro-Mechanical System (MEMS)-based digital micromirror devices for the control of the incident light field opens an avenue to high speed implementations of wavefront shaping

    Using Auditory Steady State Responses to Outline the Functional Connectivity in the Tinnitus Brain

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    BACKGROUND: Tinnitus is an auditory phantom perception that is most likely generated in the central nervous system. Most of the tinnitus research has concentrated on the auditory system. However, it was suggested recently that also non-auditory structures are involved in a global network that encodes subjective tinnitus. We tested this assumption using auditory steady state responses to entrain the tinnitus network and investigated long-range functional connectivity across various non-auditory brain regions. METHODS AND FINDINGS: Using whole-head magnetoencephalography we investigated cortical connectivity by means of phase synchronization in tinnitus subjects and healthy controls. We found evidence for a deviating pattern of long-range functional connectivity in tinnitus that was strongly correlated with individual ratings of the tinnitus percept. Phase couplings between the anterior cingulum and the right frontal lobe and phase couplings between the anterior cingulum and the right parietal lobe showed significant condition x group interactions and were correlated with the individual tinnitus distress ratings only in the tinnitus condition and not in the control conditions. CONCLUSIONS: To the best of our knowledge this is the first study that demonstrates existence of a global tinnitus network of long-range cortical connections outside the central auditory system. This result extends the current knowledge of how tinnitus is generated in the brain. We propose that this global extend of the tinnitus network is crucial for the continuos perception of the tinnitus tone and a therapeutical intervention that is able to change this network should result in relief of tinnitus

    Emotion Processing in the Visual Brain: A MEG Analysis

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    Recent functional magnetic resonance imaging (fMRI) and event-related brain potential (ERP) studies provide empirical support for the notion that emotional cues guide selective attention. Extending this line of research, whole head magneto-encephalogram (MEG) was measured while participants viewed in separate experimental blocks a continuous stream of either pleasant and neutral or unpleasant and neutral pictures, presented for 330ms each. Event-related magnetic fields (ERF) were analyzed after intersubject sensor coregistration, complemented by minimum norm estimates (MNE) to explore neural generator sources. Both streams of analysis converge by demonstrating the selective emotion processing in an early (120-170ms) and a late time interval (220-310ms). ERF analysis revealed that the polarity of the emotion difference fields was reversed across early and late intervals suggesting distinct patterns of activation in the visual processing stream. Source analysis revealed the amplified processing of emotional pictures in visual processing areas with more pronounced occipito-parieto-temporal activation in the early time interval, and a stronger engagement of more anterior, temporal, regions in the later interval. Confirming previous ERP studies showing facilitated emotion processing, the present data suggest that MEG provides a complementary look at the spread of activation in the visual processing strea

    Abnormal auditory mismatch response in tinnitus sufferers with high-frequency hearing loss is associated with subjective distress level

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    BACKGROUND: Tinnitus is an auditory sensation frequently following hearing loss. After cochlear injury, deafferented neurons become sensitive to neighbouring intact edge-frequencies, guiding an enhanced central representation of these frequencies. As psychoacoustical data [1-3] indicate enhanced frequency discrimination ability for edge-frequencies that may be related to a reorganization within the auditory cortex, the aim of the present study was twofold: 1) to search for abnormal auditory mismatch responses in tinnitus sufferers and 2) relate these to subjective indicators of tinnitus. RESULTS: Using EEG-mismatch negativity, we demonstrate abnormalities (N = 15) in tinnitus sufferers that are specific to frequencies located at the audiometrically normal lesion-edge as compared to normal hearing controls (N = 15). Groups also differed with respect to the cortical locations of mismatch responsiveness. Sources in the 90–135 ms latency window were generated in more anterior brain regions in the tinnitus group. Both measures of abnormality correlated with emotional-cognitive distress related to tinnitus (r ~ .76). While these two physiological variables were uncorrelated in the control group, they were correlated in the tinnitus group (r = .72). Concerning relationships with parameters of hearing loss (depth and slope), slope turned out to be an important variable. Generally, the steeper the hearing loss is the less distress related to tinnitus was reported. The associations between slope and the relevant neurophysiological variables are in agreement with this finding. CONCLUSIONS: The present study is the first to show near-to-complete separation of tinnitus sufferers from a normal hearing control group based on neurophysiological variables. The finding of lesion-edge specific effects and associations with slope of hearing loss corroborates the assumption that hearing loss is the basis for tinnitus development. It is likely that some central reorganization follow a damage to hearing receptors, even though the paradoxical results indicate that they most likely are somewhat different than originally assumed (see Background). One partial explanation might lie in the involvement of top-down (presumably frontal-lobe) controlled processes. A better comprehension of the exact mechanisms leading to the present results could have a broad impact on the understanding and perhaps treatment of tinnitus

    Treating Traumatized Offenders and Veterans by Means of Narrative Exposure Therapy

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    Hecker T, Hermenau K, Crombach A, Elbert T. Treating Traumatized Offenders and Veterans by Means of Narrative Exposure Therapy. Frontiers in Psychiatry. 2015;6:80
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