Parametric Probability Distribution Functions for Axon Diameters of Corpus Callosum

Axon diameter is an important neuroanatomical characteristic of the nervous system that alters in the course of neurological disorders such as multiple sclerosis. Axon diameters vary, even within a fiber bundle, and are not normally distributed. An accurate distribution function is therefore beneficial, either to describe axon diameters that are obtained from a direct measurement technique (e.g., microscopy), or to infer them indirectly (e.g., using diffusion-weighted MRI). The gamma distribution is a common choice for this purpose (particularly for the inferential approach) because it resembles the distribution profile of measured axon diameters which has been consistently shown to be non-negative and right-skewed. In this study we compared a wide range of parametric probability distribution functions against empirical data obtained from electron microscopy images. We observed that the gamma distribution fails to accurately describe the main characteristics of the axon diameter distribution, such as location and scale of the mode and the profile of distribution tails. We also found that the generalized extreme value distribution consistently fitted the measured distribution better than other distribution functions. This suggests that there may be distinct subpopulations of axons in the corpus callosum, each with their own distribution profiles. In addition, we observed that several other distributions outperformed the gamma distribution, yet had the same number of unknown parameters; these were the inverse Gaussian, log normal, log logistic and Birnbaum-Saunders distributions

Packages of Care for Epilepsy in Low- and Middle-Income Countries

In the second in a series of six articles on packages of care for mental health disorders in low- and middle-income countries, Caroline Mbuba and Charles Newton discuss treatment for epilepsy

The amygdala and anxiety after epilepsy surgery

Lee et\ua0al. (2017) show that in the basolateral amygdala (BLA), fear and reward are encoded by phasic activation of distinct populations of neurons, while anxiety results in persistent activity changes. This study raises questions about how sensory inputs are encoded in the basal amygdala

Synthesis, characterization and coordination chemistry of dibenzofuran derivatives of 1,4,7,10-tetraazacyclododecane

A 1,4-disubstituted dibenzofuran derivative of 1,4,7,10- tetraazacyclododecane (cyclen), L1, has been prepared by the direct reaction of cyclen and chloroacetyldibenzofuran and the mono-substituted derivative, L2, by reaction of chloroacetyldibenzofuran and 1,4,7-tris(t-butoxycarbonyl)-1,4,7,10- tetraazacyclododecane followed by deprotection with trifluoroacetic acid. The ligands were characterized by H and C NMR spectroscopy, IR spectroscopy and mass spectrometry. The reaction of the 1,4-disubstituted dibenzofuran cyclen, L1, with Cu(ClO)·6H O in methanol yielded crystals of [CuL1](ClO) ·MeOH·1/2HO that were suitable for single crystal structural analysis. The X-ray structure confirmed that the 1,4-disubstituted dibenzofuran cyclen had been formed. The copper(II) coordination sphere in the complex cation, [CuL1], is occupied by four nitrogen atoms from the macrocycle and an amide oxygen donor from one dibenzofuran pendant group. As is typical for copper(II)-cyclen complexes, the Cu(II) centre sits above the plane of the macrocycle nitrogen towards the oxygen donor, in this case by 0.5 . Fluorescence emission studies indicate that coordination of the macrocycle to either copper(II) or zinc(II) results in a decrease in emission with respect to the emission of the pure ligand

Language skills of school-aged children prenatally exposed to antiepileptic drugs

OBJECTIVES: Fetal exposure to some antiepileptic drugs (AEDs) carries increased risk of major birth defects, and may be associated with reduced intellectual abilities. The impact on language remains unclear. This study aimed to investigate the impact of fetal AED exposure on language skills. METHODS: Women with epilepsy and their children were recruited to this observational study through the Australian Pregnancy Register for Women with Epilepsy and Allied Disorders. Language skills of 102 AED-exposed children were assessed using the Clinical Evaluation of Language Fundamentals, fourth edition (CELF-4). Assessments were conducted blind to drug. Maternal epilepsy, pregnancy, and medical histories were obtained from prospectively collected records. RESULTS: Mean CELF-4 Core Language scores of children exposed to sodium valproate in monotherapy (mean 91.5, SD 17.5) or polytherapy (mean 73.4, SD = 22.3) were significantly below the standardized test mean of 100 (p < 0.05). Mean language scores of children exposed to carbamazepine or lamotrigine monotherapy, or polytherapy without sodium valproate, were not significantly different from normal. First-trimester sodium valproate dose was negatively correlated with language scores, and significantly predicted language scores after controlling for other group differences. CONCLUSIONS: Fetal exposure to sodium valproate increases the risk of language impairment. This should be taken into account when making treatment decisions for women with epilepsy of childbearing age