There is growing interest in the therapeutic utility of psychedelic substances, like psilocybin, for disorders characterized by distortions of the self-experience, like depression. Accumulating preclinical evidence emphasizes the role of the glutamate system in the acute action of the drug on brain and behavior; however this has never been tested in humans. Following a double-blind, placebo-controlled, parallel group design, we utilized an ultra-high field multimodal brain imaging approach and demonstrated that psilocybin (0.17 mg/kg) induced region-dependent alterations in glutamate, which predicted distortions in the subjective experience of one’s self (ego dissolution). Whereas higher levels of medial prefrontal cortical glutamate were associated with negatively experienced ego dissolution, lower levels in hippocampal glutamate were associated with positively experienced ego dissolution. Such findings provide further insights into the underlying neurobiological mechanisms of the psychedelic, as well as the baseline, state. Importantly, they may also provide a neurochemical basis for therapeutic effects as witnessed in ongoing clinical trials.

Multimodal approaches are of growing interest in the study of neural processes. To this end much attention has been paid to the integration of electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) data because of their complementary properties. However, the simultaneous acquisition of both types of data causes serious artifacts in the EEG, with amplitudes that may be much larger than those of EEG signals themselves. The most challenging of these artifacts is the ballistocardiogram (BCG) artifact, caused by pulse-related electrode movements inside the magnetic field. Despite numerous efforts to find a suitable approach to remove this artifact, still a considerable discrepancy exists between current EEG-fMRI studies. This paper attempts to clarify several methodological issues regarding the different approaches with an extensive validation based on event-related potentials (ERPs). More specifically, Optimal Basis Set (OBS) and Independent Component Analysis (ICA) based methods were investigated. Their validation was not only performed with measures known from previous studies on the average ERPs, but most attention was focused on task-related measures, including their use on trial-to-trial information. These more detailed validation criteria enabled us to find a clearer distinction between the most widely used cleaning methods. Both OBS and ICA proved to be able to yield equally good results. However, ICA methods needed more parameter tuning, thereby making OBS more robust and easy to use. Moreover, applying OBS prior to ICA can optimize the data quality even more, but caution is recommended since the effect of the additional ICA step may be strongly subject-dependent.

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In this article we describe visual perceptual abilities of a clinical population, referred for visual problems to our multidisciplinary team and assessed with the five computer tasks from the L94 visual perceptual battery. Clinical and neuroimaging findings were correlated with the findings on this task battery. Seventy children (35 males, 35 females) constituted our cohort. Age ranged from 4 to 20 years (mean 7y [SD 3y]). Forty children were born before 37 weeks gestational age. Thirty-six children had cerebral palsy (CP), of whom 24 had spastic diplegia, five had spastic hemiplegia, and four had spastic quadriplegia. Three children had ataxic CP. Perceptual visual impairment (PVI) was established in comparison to the performance age obtained on non-verbal intelligence subtests, instead of chronological age. Our results suggest that children with a history of preterm birth and a clinical CP picture are most at risk for a specific PVI. Correlations among other clinical variables did not define a clinical subgroup more at risk. Children with periventricular leucomalacia were almost equally represented in both PVI and non-PVI groups. Normal magnetic resonance imaging did not exclude the presence of PVI. In these children, however, we found another impairment profile, more in favour of dorsal stream impairment.Cerebral visual impairment (CVI) is a neurological disorder caused by dysfunction of the retrochiasmatic visual pathways and projection areas in the absence of any major ocular disease.

Antenatal maternal anxiety has been shown to be related to infant temperament, childhood disorders, and impulsivity in adolescence. This study prospectively investigated whether antenatal maternal anxiety is associated with performance on a continuous performance task. Sixty-four adolescents (mean age, 15 y; 34 boys, 30 girls) were examined with a computerized continuous performance task (CPT) measuring sustained attention. Results showed that the CPT performance of boys of mothers with high levels of state anxiety during the 12th to 22nd postmenstrual week of pregnancy declined as the task progressed: their processing speed became slower and the variability in their reaction times increased. The study controlled for the possible confounding influences of postnatal maternal anxiety, the parents' educational level, and intelligence. Establishing a link between antenatal maternal anxiety and an objective measure of sustained attention/self-regulation, our results extend the growing evidence for an association between antenatal maternal anxiety and the neurobehavioral development of the offspring up into adolescence. A growing number of studies provide evidence that child development is negatively related to heightened maternal anxiety and stress during pregnancy (1-3). Prospective longitudinal studies, using behavioral questionnaires and clinical scales administered at several moments during development up to 9 y of age, revealed that children of mothers with high anxiety during pregnancy had more difficulties with cognitive, behavioral, and emotional self-regulation as expressed in infant difficult temperament, attention regulation problems, hyperactivity, clinical diagnosis of ADHD, ADHD symptoms, conduct disorders, and emotional problems (4 -9). One explanation for these observations, which is based on experimental studies in rodents and other animals, is that, during sensitive periods of development, disturbing factors (hormones related to maternal anxiety and/or stress) exercise organizational effects that constrain the malleability of biologic systems that ultimately can predispose to disorder (10,11).At present, it is not clear during which prenatal period the human fetus is most sensitive to the negative influence of the mother's emotional state. O'Connor et al. (7,8) found anxiety at 32 wk of pregnancy to be related to behavioral and emotional problems of both boys and girls, whereas anxiety at 18 wk of pregnancy was only in girls associated with these problems. In the second wave of their longitudinal study, Van den Bergh and Marcoen (9) pinpointed 12-22 wk as the only important period predictive of ADHD symptoms and externalizing and internalizing problems. In the first part of the third wave of this study, maternal anxiety during this period was found to be related to impulsivity during performance on a divided attention task and to lower scores on two intelligence subtests (12).This article represents a second part of the third wave of the prospective study of Van den Bergh and Marcoen (9) ...