Editor's Highlight: Embryonic Exposure to the Environmental Neurotoxin BMAA Negatively Impacts Early Neuronal Development and Progression of Neurodegeneration in the Sod1-G93R Zebrafish Model of Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder leading to progressive paralysis and death within 2-5 years after diagnosis. Sporadic cases (SALS) comprise approximately 90% of cases with the remaining 10% familial (FALS) caused by mutations in approximately 27 genes. The vast heterogeneity seen in age and location of disease onset, rate of progression, and duration of disease has been linked with genetic and environmental influences in both SALS and FALS cases. Increased ALS incidence clusters in Guam, southern France, and Maryland have been linked with exposure to Beta-methylamino-L-alanine (BMAA), a nonproteinogenic amino acid produced by cyanobacteria, dinoflaggelates, and diatoms. We embryonically exposed zebrafish, Danio rerio, (transgenically overexpressing a FALS-causing SOD1-G93R mutation) to BMAA to investigate early motor neuron outgrowth in larvae and endurance and fatigability in 5-month adults. SOD1-G93R zebrafish showed decreased embryonic nerve length with increased BMAA dose, a phenotypic change mirrored in 5-month performance measures of weaker swimming and increased fatigability. In contrast, transgenic fish overexpressing wild-type SOD1 were resistant to phenotypic changes, indicating a potential neuroprotective function of healthy SOD1. We show that the etiology of genetic ALS animal models can be influenced by environmental exposures, and that embryonic toxin exposures can result in changes to both early and adult measures. We demonstrate that zebrafish can be a robust model for investigating causes of ALS heterogeneity. Establishing these links between developmental and adult ALS-like symptoms in the zebrafish increases the power of this model for toxicological and drug screens.

Advanced MR imaging of cortical dysplasia with or without neoplasm: a report of two cases.

We herein describe two cases of patients with epilepsy with occipital lobe cortical dysplasia who were studied with both MR spectroscopy and MR diffusion imaging in addition to conventional MR imaging. Greater diffusion abnormalities, as well as more marked decreases in N-acetylaspartate, were observed to occur in the patient harboring a low grade neoplasm within an area of cortical dysplasia than in the patient with cortical dysplasia alone.

Functional MRI study of semantic and phonological language processing in bilingual subjects: preliminary findings.

The objective of the study was to explore differences in regional fMRI activation topography and lateralization between semantic and phonological tasks performed in English and Spanish in bilingual individuals. Eight bilingual (primary Spanish and secondary English-speaking) individuals performed fMRI noun-verb association and rhyming tasks in both Spanish and English. Functional dataset analysis within Statistical Parametric Mapping (SPM99) with overlay on T1-weighted anatomic images was performed. Significantly higher laterality indices were noted in the semantic tasks as compared with the phonological tasks in the anterior regions of interest comprising the frontal and superior temporal lobes. A task subtraction analysis demonstrated right hemispheric (inferior frontal gyrus and supramarginal gyrus) foci of significantly increased activation in the combined language phonological tasks compared to the combined language semantic tasks; similarly prominent right hemispheric activation was seen in the English phonological-English semantic subtraction, but the analogous Spanish task subtraction revealed no task-related differences. This divergence in activation topography between semantic and phonological tasks performed in the nonnative language, but not in the primary language, suggests that neural networks utilized for phonological and semantic language processing in the nonnative language may not be as similar as those in the primary language.