Showing papers by "Chantal Kemner published in 2007"
McMaster University1, University of Toronto2, Dalhousie University3, Pennsylvania State University4, Nationwide Children's Hospital5, University of Iowa6, University of Miami7, University of South Carolina8, University of Paris9, Pasteur Institute10, University of Gothenburg11, Icahn School of Medicine at Mount Sinai12, Stanford University13, Vanderbilt University14, Johns Hopkins University15, University of North Carolina at Chapel Hill16, University of California, Los Angeles17, University of Pennsylvania18, Washington University in St. Louis19, University of Chicago20, Harvard University21, Emory University22, George Washington University23, Yale University24, University of Utah25, University of Washington26, University of Pittsburgh27, University of California, Irvine28, Veterans Health Administration29, University of Rochester30, University of Toulouse31, German Cancer Research Center32, Goethe University Frankfurt33, National and Kapodistrian University of Athens34, University of Bologna35, Utrecht University36, Guy's Hospital37, King's College London38, University of Cambridge39, University of Manchester40, Newcastle University41, University of Oxford42, University of Illinois at Chicago43, University of Michigan44, Centre Hospitalier Universitaire de Toulouse45, McGill University46, Autism Speaks47
TL;DR: Linkage and copy number variation analyses implicate chromosome 11p12–p13 and neurexins, respectively, among other candidate loci, highlighting glutamate-related genes as promising candidates for contributing to ASDs.
Abstract: Autism spectrum disorders (ASDs) are common, heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome heterogeneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1,181 [corrected] families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamate-related genes as promising candidates for contributing to ASDs.
1,338 citations
TL;DR: Methylphenidate's ameliorating effects might be established through its influence on brain networks including posterior (parietal) cortex, enabling children with ADHD to allocate more attention to significant events.
118 citations
TL;DR: It is suggested that seeing a facial expression, an emotional body expression or hearing an emotional tone of voice all activate the affect program corresponding to the emotion displayed, and spontaneous facial expression is more akin to an emotional reaction than to facial mimicry and imitation of the seen face stimulus.
Abstract: Observing facial expressions automatically prompts imitation, as can be seen with facial electromyography. To investigate whether this reaction is driven by automatic mimicry or by recognition of the emotion displayed we recorded electromyograph responses to presentations of facial expressions, face-voice combinations and bodily expressions, which resulted from happy and fearful stimuli. We observed emotion-specific facial muscle activity (zygomaticus for happiness, corrugator for fear) for all three stimulus categories. This indicates that spontaneous facial expression is more akin to an emotional reaction than to facial mimicry and imitation of the seen face stimulus. We suggest that seeing a facial expression, an emotional body expression or hearing an emotional tone of voice all activate the affect program corresponding to the emotion displayed.
109 citations
TL;DR: This study provides evidence for enhanced sensitivity to facial cues at the level of reflex-like emotional responses in individuals with PDD and argues against impairments in crossmodal affect processing at this level of perception.
Abstract: Background: Despite extensive research, it is still debated whether impairments in social skills of individuals with pervasive developmental disorder (PDD) are related to specific deficits in the early processing of emotional information. We aimed to test both automatic processing of facial affect as well as the integration of auditory and visual emotion cues in individuals with PDD. Methods: In a group of high-functioning adult individuals with PDD and an age- and IQ-matched control group, we measured facial electromyography (EMG) following presentation of visual emotion stimuli (facial expressions) as well as the presentation of audiovisual emotion pairs (faces plus voices). This emotionally driven EMG activity is considered to be a direct correlate of automatic affect processing that is not under intentional control. Results: Our data clearly indicate that among individuals with PDD facial EMG activity is heightened in response to happy and fearful faces, and intact in response to audiovisual affective information. Conclusions: This study provides evidence for enhanced sensitivity to facial cues at the level of reflex-like emotional responses in individuals with PDD. Furthermore, the findings argue against impairments in crossmodal affect processing at this level of perception. However, given how little comparative work has been done in the area of multisensory perception, there is certainly need for further exploration.
103 citations
TL;DR: High-functioning adult subjects with Autism Spectrum Disorder as well as age- and IQ-matched adults were tested using a task that evokes illusory visual stimuli, by presenting sounds concurrently with visual flashes, and in both groups the number of sounds presented significantly affected theNumber of flashes perceived, yet there was no difference between groups.
Abstract: Patients diagnosed with Autism Spectrum Disorder, show impaired integration of information across different senses. The processing-level from which this impairment originates, however, remains unclear. We investigated low-level integration of auditory and visual stimuli in subjects with Autism Spectrum Disorder. High-functioning adult subjects with Autism Spectrum Disorder as well as age- and IQ-matched adults were tested using a task that evokes illusory visual stimuli, by presenting sounds concurrently with visual flashes. In both groups the number of sounds presented significantly affected the number of flashes perceived, yet there was no difference between groups. This finding implicates that any problems arising from integrating auditory and visual information must stem from higher processing stages in high-functioning adults with Autism Spectrum Disorder.
92 citations
TL;DR: Results from the present study show that in children, a more diffuse brain network is involved in executive control processing (conflict monitoring) in the Nogo-N2 time window than in adults.
90 citations
TL;DR: Results indicate that high-functioning individuals with PDD and their parents are able to process visual stimuli that rely on early or late processing in the magnocellular-dorsal and parvo cellular-ventral pathways as well as controls.
Abstract: The authors assessed visual information processing in high-functioning individuals with pervasive developmental disorders (PDD) and their parents. The authors used tasks for contrast sensitivity, motion, and form perception to test visual processing occurring relatively early and late in the magnocellular-dorsal and parvocellular-ventral pathways. No deficits were found in contrast sensitivity for low or high spatial frequencies or for motion or form perception between individuals with PDD in comparison with a matched control group. Individuals with PDD performed equally with or better than controls on motion detection tasks. In addition, the authors did not find differences on any of the tasks between parents of the PDD group and matched control parents. These results indicate that high-functioning individuals with PDD and their parents are able to process visual stimuli that rely on early or late processing in the magnocellular-dorsal and parvocellular-ventral pathways as well as controls.
84 citations
TL;DR: Investigation of deficits in spatial frequency processing at an early sensory level in children with PDD suggests peculiarities in PDD subjects with respect to these stimuli might be related to an abnormality in more fundamental visual processes.
55 citations
TL;DR: Results argue against the idea that this is due to a reduced face expertise on the part of the children with PDD, but instead support an abnormality in spatial frequency processing.
Abstract: Both a reduced face expertise and a basic abnormality in visual information, e.g. spatial frequency, processing have been proposed as possible causes of the abnormal face processing in Pervasive Developmental Disorder (PDD). This study investigated both the roles of expertise and spatial frequency for face processing in PDD. Event-related potentials (ERPs) and dipole sources were measured in response to (upright/inverted) high- and low-pass filtered faces, houses, and stimuli for which children with PDD were experts. ERP analyses for specific posterior electrodes showed no differences between children with PDD and matched controls, but source analyses did. These showed that controls activated specialized brain sources for the processing of faces, which was dependent on low spatial frequency content. However, children with PDD did not. Importantly, present results argue against the idea that this is due to a reduced face expertise on the part of the children with PDD, but instead support an abnormality in spatial frequency processing.
29 citations
TL;DR: Children with PDD showed a normal performance on the contour integration task, suggesting that neurons in the primary visual cortex of children withPDD can effectively integrate the activity of local detectors that process different aspects of the same object information by making use of long-range lateral connections.
28 citations
TL;DR: By measuring visual evoked potentials during a texture discrimination task, it is shown that general fluid intelligence shows a strong correlation with processing speed in recurrent visual networks, while there is no correlation with speed of feedforward connections.
Abstract: Studies on the neural basis of general fluid intelligence strongly suggest that a smarter brain processes information faster. Different brain areas, however, are interconnected by both feedforward and feedback projections. Whether both types of connections or only one of the two types are faster in smarter brains remains unclear. Here we show, by measuring visual evoked potentials during a texture discrimination task, that general fluid intelligence shows a strong correlation with processing speed in recurrent visual networks, while there is no correlation with speed of feedforward connections. The hypothesis that a smarter brain runs faster may need to be refined: a smarter brain's feedback connections run faster.
TL;DR: The results show no evidence for specific abnormalities in looking behavior to either faces or to complex stimuli in high functioning children with PDD.