Neurology

Most people are left-hemisphere dominant for language. However the neuroanatomy of language lateralization is not fully understood. By combining functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), we studied whether language lateralization is associated with cerebral white-matter (WM) microstructure. Sixteen healthy, left-handed women aged 20-25 were included in the study. Left-handers were targeted in order to increase the chances of involving subjects with atypical language lateralization. Language lateralization was determined by fMRI using a verbal fluency paradigm. Tract-based spatial statistics analysis of DTI data was applied to test for WM microstructural correlates of language lateralization across the whole brain. Fractional anisotropy and mean diffusivity were used as indicators of WM microstructural organization. Right-hemispheric language dominance was associated with reduced microstructural integrity of the left superior longitudinal fasciculus and left-sided parietal lobe WM. In left-handed women, reduced integrity of the left-sided language related tracts may be closely linked to the development of right hemispheric language dominance. Our results may offer new insights into language lateralization and structure-function relationships in human language system.

Caffeine is the most often used psychoactive substance. Caffeine may influence neuroplasticity in animals. We investigated the relationship between caffeine intake (coffee consumption) and brain morphology. Fortyfive healthy, non-smoking women aged 19-30 were included in the present study. We used semi-automatic user-independent MR volumetry and voxel-based morphometry. We investigated the relationship between caffeine intake (coffee consumption) and the volumes of the cortical brain structures where caffeine is supposed to act. We found that high-level and low-level caffeine intake was associated with a larger hippocampus compared to moderate-level caffeine intake. The other brain structures showed no association with coffee consumption or caffeine intake. The U-shape association between caffeine concentration and its effect has already been described in some experimental studies. To our knowledge this is one of the very first studies, which tries to find an association between brain morphology and coffee consumption or caffeine intake in humans using MR imaging.

Leber's hereditary optic neuropathy (LHON) is associated with point mutations in the mitochondrial DNA (mtDNA), coding for a mitochondrial respiratory chain complex I subunit. It is characterized by bilateral, usually sequential, optic neuropathy and may co-occur with multiple sclerosis-like white matter lesions. Despite repeated clinical reports including MRI and histopathological examination of the visual system, neuropathological descriptions of LHON associated with multiple sclerosis-like syndrome are lacking. We present here the case of a female patient with a point mutation at nucleotide position T14484C, who suffered from relapsing episodes of visual loss of both eyes and consecutively developed Hashimoto thyroiditis as well as widespread demyelinating CNS lesions outside the visual system. She died of bronchopneumonia at the age of 44 years, after a disease duration of 19 years, with progressive deterioration, epileptic seizures and immobility. Immunohistochemical analysis on formalin-fixed and paraffin-embedded tissue reveals a spectrum of neuropathological changes, including actively and inactively demyelinating plaques in the white matter and optic nerve, vacuolation and cystic necrosis with CD8-positive T cells in the frontal lobe, axonal damage, and vacuolation of white matter. Tissue destruction is associated with upregulation of mitochondrial manganese superoxide dismutase within the lesions and an increase in the expression of inducible nitric oxide synthase within macrophages and microglia. This variable phenotype of extraoptic LHON disease suggests that mtDNA mutations may affect the nervous system on a common metabolic basis and occasionally may aggravate or initiate autoimmune pathology.

Background: It is unclear whether the hippocampal abnormality in temporal lobe epilepsy (TLE) is a consequence or the cause of afebrile or febrile seizures (FSs). We investigated whether hippocampal abnormalities are present in healthy adults >15 years after a simple FS. Methods: Eight healthy subjects (5 men) with a history of simple FS (FS+ group) and eight sex-and aged-matched control subjects (FS-group) were investigated by three MR methods: blinded visual inspection of the MRI pictures; automatic voxelbased volumetry; and T2 relaxation time measurements. Results: The mean total volume of the two hippocampi was 5.36 ± 1.33 cm 3 in the FS+ group and 6.63 ± 1.46 cm 3 in the FS-group (p = 0.069). The T2 values in the anterior part of the left hippocampus (p = 0.036) and in the middle part of the right hippocampus (p = 0.025) were elevated in the FS+ subjects. The mean volume of the right hippocampus was 3.05 ± 0.8 cm 3 in the FS+ men and 4.05 ± 0.48 cm 3 in the FS-men (p = 0.043). The mean total volume of the two hippocampi was 5.38 ± 1.4 cm 3 in the FS+ men and 7.48 ± 1.14 cm 3 in the FS-men (p = 0.043). There were three FS+ men in whom hippocampal abnormalities including hippocampal sclerosis (HS) and dysgenesis were observed on visual inspection. Conclusions: A history of simple FS in childhood can be associated with hippocampal abnormalities in adults. These abnormalities are probably more pronounced in men. Simple FS may not be as a benign event as previously thought. Our findings suggest that hippocampal abnormalities associated with FS are not necessarily epileptogenic.

The interleukin (IL) -23/IL-17 cytokine axis has been suggested to play an important role in the development of several autoimmune diseases including multiple sclerosis. Here, we compared the prevalence of C2370A single nucleotide polymorphism (SNP) in the 3 untranslated region (3 UTR) of the IL-23 receptor (IL23R) between 223 patients with relapsing-remitting multiple sclerosis (RRMS) and 200 healthy controls. The A2370A genotype was significantly over-represented among patients with RRMS (10.8%) and RRMS exhibiting oligoclonal bands in the cerebrospinal fluid (12.9%) when compared to healthy subjects (5.50%). Multiple regression analysis revealed that presence of AA genotype provides a two-fold risk for the development of multiple sclerosis (OR = 2.072, 95% CI: 0.988-4.347, p < 0.05). These data indicate that IL23R represents a novel shared susceptibility gene as its association with inflammatory bowel disease (IBD) has recently been verified.