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Search Results: 1 - 10 of 32704 matches for " Daniel Brandeis "
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Fast, visual specialization for reading in English revealed by the topography of the N170 ERP response
Urs Maurer, Daniel Brandeis, Bruce D McCandliss
Behavioral and Brain Functions , 2005, DOI: 10.1186/1744-9081-1-13
Abstract: Extending previous research in German [1], we use a high-density channel array to characterize the N170 topography for reading-related perceptual expertise in English, a language with inconsistent spelling-to-sound mapping. N170 effects related to overall reading-related expertise are defined by contrasting responses to visual words versus novel symbol strings. By contrasting each of these conditions to pseudowords, we examined how this reading-related N170 effect generalizes to well-ordered novel letter strings.A sample-by-sample permutation test computed on word versus symbol ERP topographies revealed differences during two time windows corresponding to the N170 and P300 components. Topographic centroid analysis of the word and symbol N170 demonstrated significant differences in both left-right as well as inferior-superior dimensions. Words elicited larger N170 negativities than symbols at inferior occipito-temporal channels, with the maximal effect over left inferior regions often unsampled in conventional electrode montages. Further contrasts produced inferior-superior topographic effects for the pseudoword-symbol comparison and left-lateralized topographic effects for the word-pseudoword comparison.Fast specialized perception related to reading experience produces an N170 modulation detectable across different EEG systems and different languages. Characterization of such effects may be improved by sampling with greater spatial frequency recordings that sample inferior regions. Unlike in German, reading-related expertise effects in English produced only partial generalization in N170 responses to novel pseudowords. The topographic inferior-superior N170 differences may reflect general perceptual expertise for orthographic strings, as it was found for words and pseudowords across both languages. The topographic left-right N170 difference between words and pseudowords was only found in English, and may suggest that ambiguity in pronunciating novel pseudowords due
Simultaneous EEG-fMRI during a Working Memory Task: Modulations in Low and High Frequency Bands
Lars Michels,Kerstin Bucher,Rafael Lüchinger,Peter Klaver,Ernst Martin,Daniel Jeanmonod,Daniel Brandeis
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010298
Abstract: EEG studies of working memory (WM) have demonstrated load dependent frequency band modulations. FMRI studies have localized load modulated activity to the dorsolateral prefrontal cortex (DLPFC), medial prefrontal cortex (MPFC), and posterior parietal cortex (PPC). Recently, an EEG-fMRI study found that low frequency band (theta and alpha) activity negatively correlated with the BOLD signal during the retention phase of a WM task. However, the coupling of higher (beta and gamma) frequencies with the BOLD signal during WM is unknown.
Discovering Robustness Amongst CBIR Features
Brandeis Marshall
International Journal of Web & Semantic Technology , 2012,
Abstract: Digital photography faces the challenges of image storage, retrieval and provenance at the consumer and commercial level. One major obstacle is in the computational cost of image processing. Solutions rangefrom using high-throughput computing systems to automatic image annotation. Consumers can not dedicate computing systems to image processing and handling nor do consumers have large-scale image repositories to make automatic image annotation effective. Nevertheless, we consider an alternative approach: reducing computational cost in image processing. Using a 25,000 image collection, we consider using a sub- set of image features to evaluate image similarity. We discover several robust features displaying comparable relevancy performance with the additional benefit of reduced processing cost.
Developmental Changes of BOLD Signal Correlations with Global Human EEG Power and Synchronization during Working Memory
Lars Michels, Rafael Lüchinger, Thomas Koenig, Ernst Martin, Daniel Brandeis
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039447
Abstract: In humans, theta band (5–7 Hz) power typically increases when performing cognitively demanding working memory (WM) tasks, and simultaneous EEG-fMRI recordings have revealed an inverse relationship between theta power and the BOLD (blood oxygen level dependent) signal in the default mode network during WM. However, synchronization also plays a fundamental role in cognitive processing, and the level of theta and higher frequency band synchronization is modulated during WM. Yet, little is known about the link between BOLD, EEG power, and EEG synchronization during WM, and how these measures develop with human brain maturation or relate to behavioral changes. We examined EEG-BOLD signal correlations from 18 young adults and 15 school-aged children for age-dependent effects during a load-modulated Sternberg WM task. Frontal load (in-)dependent EEG theta power was significantly enhanced in children compared to adults, while adults showed stronger fMRI load effects. Children demonstrated a stronger negative correlation between global theta power and the BOLD signal in the default mode network relative to adults. Therefore, we conclude that theta power mediates the suppression of a task-irrelevant network. We further conclude that children suppress this network even more than adults, probably from an increased level of task-preparedness to compensate for not fully mature cognitive functions, reflected in lower response accuracy and increased reaction time. In contrast to power, correlations between instantaneous theta global field synchronization and the BOLD signal were exclusively positive in both age groups but only significant in adults in the frontal-parietal and posterior cingulate cortices. Furthermore, theta synchronization was weaker in children and was –in contrast to EEG power– positively correlated with response accuracy in both age groups. In summary we conclude that theta EEG-BOLD signal correlations differ between spectral power and synchronization and that these opposite correlations with different distributions undergo similar and significant neuronal developments with brain maturation.
Cognitive-electrophysiological indices of attentional and inhibitory processing in adults with ADHD: familial effects
Gráinne McLoughlin, Philip Asherson, Bjoern Albrecht, Tobias Banaschewski, Aribert Rothenberger, Daniel Brandeis, Jonna Kuntsi
Behavioral and Brain Functions , 2011, DOI: 10.1186/1744-9081-7-26
Abstract: Using a family design, we compared 20 fathers of children with the combined subtype of ADHD with 21 adults with ADHD combined subtype and 20 controls in event-related potential indices of preparatory states and subsequent response inhibition processing as elicited by a cued continuous performance task.Fathers of children with ADHD exhibited significantly weaker orienting attention to cues and inhibitory processing than the controls but not the ADHD sample.These findings provide evidence for the familial association of attentional orienting and response inhibition processes with ADHD in adults and indicate a familial and neurobiological link between ADHD in children and adults.Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that persists into adulthood in around 65% of cases and is associated with high levels of clinical, psychosocial and economic burden [1,2]. ADHD in adults is recognised as a valid and reliable disorder that is a developmental outcome of ADHD in children and shares many of the same clinical features with ADHD in childhood, including the cardinal symptoms of inattentiveness, overactivity and impulsivity [3-5]. ADHD tends to run in families with increased rates of ADHD among the siblings [6-8] and parents [6,9] of children with ADHD. Twin studies indicate that the familial risk for ADHD results from genetic influences with heritability estimates averaging around 76% during childhood and adolescence [10]. Due to the high heritability, aetiological investigations have focused primarily on the role of genetic factors and on the identification of intermediate phenotypes, such as cognitive and neurobiological processes, that potentially mediate genetic effects on behaviour [11-13].Key requirements for intermediate phenotypes include association with the disorder, indicated by case-control differences, and presence in unaffected first-degree relatives of affected individuals with levels significantly higher than in t
Electrophysiological evidence for abnormal preparatory states and inhibitory processing in adult ADHD
Gráinne McLoughlin, Bjoern Albrecht, Tobias Banaschewski, Aribert Rothenberger, Daniel Brandeis, Philip Asherson, Jonna Kuntsi
Behavioral and Brain Functions , 2010, DOI: 10.1186/1744-9081-6-66
Abstract: The objective of this paper was to investigate event-related potential indices of preparatory states and subsequent response inhibition processing in adults with ADHD. Two cued continuous performance tasks were presented to 21 adults meeting current criteria for adult ADHD and combined type ADHD in childhood, and 20 controls.The ADHD group exhibited significantly weaker orienting attention to cues, cognitive preparation processes and inhibitory processing. In addition, we observed a strong correlation between the resources allocated to orienting to cues and the strength of the subsequent response strength control processes, suggesting that orienting deficits partly predict and determine response control deficits in ADHD.These findings closely resemble those previously found in children with ADHD, which indicate that there is not a core response inhibition deficit in ADHD. These findings therefore suggest the possibility of developmental stability into adulthood of the underlying abnormal processes in ADHD.Adult ADHD (AD-ADHD) is recognised as a valid and reliable disorder that shares many features with ADHD in childhood [1-3]. Prevalence and longitudinal studies indicate that the cardinal symptoms of ADHD, inattentiveness, overactivity and impulsiveness, persist into adulthood in the majority of cases [4,5]. As some symptoms of ADHD decline in severity throughout development, many individuals who fulfilled symptom criteria for ADHD as children may no longer reach full criteria for ADHD as adults, even though persistence of some symptoms continues to cause significant clinical impairments [6-8].Several theories postulate deficits in ADHD that have effects across many executive functions, such as response inhibition, attention or working memory, with some data further suggesting that this may be particularly true for a subgroup of ADHD [9]. A meta-analysis confirmed that children with ADHD often perform more poorly than control children on tasks measuring inhibition,
Controlled evaluation of a neurofeedback training of slow cortical potentials in children with Attention Deficit/Hyperactivity Disorder (ADHD)
Renate Drechsler, Marc Straub, Mirko Doehnert, Hartmut Heinrich, Hans-Christoph Steinhausen, Daniel Brandeis
Behavioral and Brain Functions , 2007, DOI: 10.1186/1744-9081-3-35
Abstract: To evaluate the specificity of a neurofeedback training of slow cortical potentials, a twofold strategy was pursued: First, the efficacy of neurofeedback training was compared to a group training program for children with ADHD. Secondly, the extent of improvements observed in the neurofeedback group in relation to successful regulation of cortical activation was examined. Parents and teachers rated children's behaviour and executive functions before and after treatment. In addition, children underwent neuropsychological testing before and after training.According to parents' and teachers' ratings, children of the neurofeedback training group improved more than children who had participated in a group therapy program, particularly in attention and cognition related domains. On neuropsychological measures children of both groups showed similar improvements. However, only about half of the neurofeedback group learned to regulate cortical activation during a transfer condition without direct feedback. Behavioural improvements of this subgroup were moderately related to neurofeedback training performance, whereas effective parental support accounted better for some advantages of neurofeedback training compared to group therapy according to parents' and teachers' ratings.There is a specific training effect of neurofeedback of slow cortical potentials due to enhanced cortical control. However, non-specific factors, such as parental support, may also contribute to the positive behavioural effects induced by the neurofeedback training.Although stimulant medication has proven as the most efficacious strategy in the treatment of ADHD, there is a considerable need for effective treatment alternatives to help the sizeable number of children who do not respond to medication, suffer from intolerable side effects or whose parents are reluctant to administer stimulant medication to their children. In addition, stimulant medication seems to alleviate primary symptoms of ADHD in child
Response inhibition deficits in externalizing child psychiatric disorders: An ERP-study with the Stop-task
Bj?rn Albrecht, Tobias Banaschewski, Daniel Brandeis, Hartmut Heinrich, Aribert Rothenberger
Behavioral and Brain Functions , 2005, DOI: 10.1186/1744-9081-1-22
Abstract: A Stop-task was used to measure specific aspects of response inhibition in 10 children with attention-deficit hyperactivity disorder (AD/HD), 8 children with oppositional defiant disorder/conduct disorder (ODD/CD), 11 children with comorbid AD/HD+ODD/CD and 11 normal controls. All children were between 8 and 14 years old. Event-related potentials and behavioural responses were recorded. An initial go-signal related microstate, a subsequent Stop-signal related N200, and performance measures were analyzed using ANCOVA with age as covariate.Groups did not differ in accuracy or reaction time to the Go-stimuli. However, all clinical groups displayed reduced map strength in a microstate related to initial processing of the Go-stimulus compared to normal controls, whereas topography did not differ. Concerning motor response inhibition, the AD/HD-only and the ODD/CD-only groups displayed slower Stop-signal reaction times (SSRT) and Stop-failure reaction time compared to normal controls. In children with comorbid AD/HD+ODD/CD, Stop-failure reaction-time was longer than in controls, but their SSRT was not slowed. Moreover, SSRT in AD/HD+ODD/CD was faster than in AD/HD-only or ODD/CD-only. The AD/HD-only and ODD/CD-only groups displayed reduced Stop-N200 mean amplitude over right-frontal electrodes. This effect reached only a trend for comorbid AD/HD+ODD/CD.Following similar attenuations in initial processing of the Go-signal in all clinical groups compared to controls, distinct Stop-signal related deficits became evident in the clinical groups. Both children with AD/HD and ODD/CD showed deficits in behavioural response-inhibition accompanied by decreased central conflict signalling or inhibition processes. Neither behavioural nor neural markers of inhibitory deficits as found in AD/HD-only and ODD/CD-only were additive. Instead, children with comorbid AD/HD+ODD/CD showed similar or even less prominent inhibition deficits than the other clinical groups. Hence, the AD/HD+ODD/CD
Time-Resolved Influences of Functional DAT1 and COMT Variants on Visual Perception and Post-Processing
Stephan Bender, Thomas Rellum, Christine Freitag, Franz Resch, Marcella Rietschel, Jens Treutlein, Christine Jennen-Steinmetz, Daniel Brandeis, Tobias Banaschewski, Manfred Laucht
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041552
Abstract: Background Dopamine plays an important role in orienting and the regulation of selective attention to relevant stimulus characteristics. Thus, we examined the influences of functional variants related to dopamine inactivation in the dopamine transporter (DAT1) and catechol-O-methyltransferase genes (COMT) on the time-course of visual processing in a contingent negative variation (CNV) task. Methods 64-channel EEG recordings were obtained from 195 healthy adolescents of a community-based sample during a continuous performance task (A-X version). Early and late CNV as well as preceding visual evoked potential components were assessed. Results Significant additive main effects of DAT1 and COMT on the occipito-temporal early CNV were observed. In addition, there was a trend towards an interaction between the two polymorphisms. Source analysis showed early CNV generators in the ventral visual stream and in frontal regions. There was a strong negative correlation between occipito-temporal visual post-processing and the frontal early CNV component. The early CNV time interval 500–1000 ms after the visual cue was specifically affected while the preceding visual perception stages were not influenced. Conclusions Late visual potentials allow the genomic imaging of dopamine inactivation effects on visual post-processing. The same specific time-interval has been found to be affected by DAT1 and COMT during motor post-processing but not motor preparation. We propose the hypothesis that similar dopaminergic mechanisms modulate working memory encoding in both the visual and motor and perhaps other systems.
Dopamine Inactivation Efficacy Related to Functional DAT1 and COMT Variants Influences Motor Response Evaluation
Stephan Bender, Thomas Rellum, Christine Freitag, Franz Resch, Marcella Rietschel, Jens Treutlein, Christine Jennen-Steinmetz, Daniel Brandeis, Tobias Banaschewski, Manfred Laucht
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0037814
Abstract: Background Dopamine plays an important role in orienting, response anticipation and movement evaluation. Thus, we examined the influence of functional variants related to dopamine inactivation in the dopamine transporter (DAT1) and catechol-O-methyltransferase genes (COMT) on the time-course of motor processing in a contingent negative variation (CNV) task. Methods 64-channel EEG recordings were obtained from 195 healthy adolescents of a community-based sample during a continuous performance task (A-X version). Early and late CNV as well as motor postimperative negative variation were assessed. Adolescents were genotyped for the COMT Val158Met and two DAT1 polymorphisms (variable number tandem repeats in the 3′-untranslated region and in intron 8). Results The results revealed a significant interaction between COMT and DAT1, indicating that COMT exerted stronger effects on lateralized motor post-processing (centro-parietal motor postimperative negative variation) in homozygous carriers of a DAT1 haplotype increasing DAT1 expression. Source analysis showed that the time interval 500–1000 ms after the motor response was specifically affected in contrast to preceding movement anticipation and programming stages, which were not altered. Conclusions Motor slow negative waves allow the genomic imaging of dopamine inactivation effects on cortical motor post-processing during response evaluation. This is the first report to point towards epistatic effects in the motor system during response evaluation, i.e. during the post-processing of an already executed movement rather than during movement programming.
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