Publications

Abstract

Native speakers of Dutch do not always adhere to prescriptive grammar rules in their daily speech. These grammatical norm violations can elicit emotional reactions in language purists, mostly high-educated people, who claim that for them these constructions are truly ungrammatical. However, linguists generally assume that grammatical norm violations are in fact truly grammatical, especially when they occur frequently in a language. In an fMRI study we investigated the processing of grammatical norm violations in the brains of language purists, and compared them with truly grammatical and truly ungrammatical sentences. Grammatical norm violations were found to be unique in that their processing resembled not only the processing of truly grammatical sentences (in left medial Superior Frontal Gyrus and Angular Gyrus), but also that of truly ungrammatical sentences (in Inferior Frontal Gyrus), despite what theories of grammar would usually lead us to believe

Abstract

Communication and integration of information between brain regions plays a key role in healthy brain function. Conversely, disruption in brain communication may lead to cognitive and behavioral problems. Autism is a neurodevelopmental disorder that is characterized by impaired social interactions and aberrant basic information processing. Aberrant brain connectivity patterns have indeed been hypothesized to be a key neural underpinning of autism. In this study, graph analytical tools are used to explore the possible deviant functional brain network organization in autism at a very early stage of brain development. Electroencephalography (EEG) recordings in 12 toddlers with autism (mean age 3.5 years) and 19 control subjects were used to assess interregional functional brain connectivity, with functional brain networks constructed at the level of temporal synchronization between brain regions underlying the EEG electrodes. Children with autism showed a significantly increased normalized path length and reduced normalized clustering, suggesting a reduced global communication capacity already during early brain development. In addition, whole brain connectivity was found to be significantly reduced in these young patients suggesting an overall under-connectivity of functional brain networks in autism. Our findings support the hypothesis of abnormal neural communication in autism, with deviating effects already present at the early stages of brain development

Abstract

Atypical visual perception in people with autism spectrum disorders (ASD) is hypothesized to stem from an imbalance in excitatory and inhibitory processes in the brain. We used neuronal oscillations in the gamma frequency range (30 – 90 Hz), which emerge from a balanced interaction of excitation and inhibition in the brain, to assess contextual modulation processes in early visual perception. Electroencephalography was recorded in 12 high-functioning adults with ASD and 12 age- and IQ-matched control participants. Oscilla- tions in the gamma frequency range were analyzed in response to stimuli consisting of small line-like elements. Orientation-speci fi c contextual modulation was manipulated by parametrically increasing the amount of homogeneously oriented elements in the stimuli. The stimuli elicited a strong steady-state gamma response around the refresh-rate of 60 Hz, which was larger for controls than for participants with ASD. The amount of orientation homogeneity (contextual modulation) in fl uenced the gamma response in control subjects, while for subjects with ASD this was not the case. The atypical steady-state gamma response to contextual modulation in subjects with ASD may capture the link between an imbalance in excitatory and inhibitory neuronal processing and atypical visual processing in ASD