Réka Horváth

History of simple febrile seizures is associated with hippocampal abnormalities in adults

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.

Are there any gender differences in the hippocampus volume after head-size correction? A volumetric and voxel-based morphometric study

Previous findings on normal sexual dimorphism in hippocampal volume have not always been consistent. This study investigated gender differences in hippocampal volume using different head-size correction strategies. T1-weighted MR images were collected in 99 healthy, Caucasian, university students (66 female subjects; mean age: 23.1 ± 2.3, range: 19-31 years). Sexual dimorphism in hippocampus was investigated by automated MRI volumetry and voxel-based morphometry (VBM) using both general linear model (GLM) and proportion head-size correction strategies. Absolute hippocampal volumes were larger in men than women. After adjusting for head-size, the proportion method indicated larger hippocampi in women than men, while no gender differences were found using the GLM approach. Investigating absolute hippocampal volumes in 15 head-size matched pairs of males and females indicated no gender differences. We suggest that there is no sexual dimorphism in hippocampal size and the apparent gender differences found by the proportion method may have more to do with head-size than with sex. The GLM and proportion head-size correction strategies are not interchangeable and may yield different results. The importance of the present findings is mostly related to scientific reproducibility across MRI volumetry or VBM studies.

Does obstetric brachial plexus injury influence speech dominance

Right‐handedness and left‐sided language lateralization is an unresolved mystery with unknown cause/effect relations. Most studies suggest that the language lateralization is related to a fundamental brain asymmetry: right‐handedness may be secondary. We analyzed the possibility of an opposite cause/effect relation: whether asymmetric hand usage (as a cause) can influence language lateralization (as a consequence).

Circadian expression of Bmal1 and serotonin-N-acetyltransferase mRNAs in chicken retina cells and pinealocytes in vivo and in vitro.

Unlike mammals, rhythmic changes in serotonin N-acetyltransferase (arylalkylamine N-acetyltransferase [AANAT]) transcripts in chicken pineal cells are controlled by an oscillator located in the pinealocytes themselves, which is comprised of clock genes. A similar clock-dependent pathway has been postulated to regulate the retinal melatonin rhythm. In chicken retinal photoreceptor cells and pinealocytes, the chicken AANAT gene (cAANAT) is coexpressed with clock genes, including cBmal1 and cClock, which might regulate cAANAT transcription. Here, we have studied the temporal profile of cBmal1, cClock, and cAANAT mRNA expression in retinal cells in vivo with chickens housed in a 14/10-h light/dark (LD) cycle for 2 wk and in vitro cultured in a superfusion system for 4 LD cycles. mRNA levels of these genes were analyzed by RT-PCR and compared with their corresponding pineal transcripts. cBmal1 mRNA showed a peak during the light phase between Zeitgeber time (ZT) 8 and 10, preceding the amplitude of the nocturnal increase in cAANAT expression at ZT 16–17. Retinal cBmal1 and cAANAT mRNAs exhibited less robust cycling than their corresponding pineal transcripts in the same animal. cClock mRNA levels failed to exhibit a well-detectable rhythm. The phase of the rhythms of retinal cBmal1 and cAANAT mRNAs suggests a link between retinal cBmal1 and cAANAT expressions similar to the regulation of pineal cAANAT transcription. Based on the highly conserved nature of the clockwork, it is reasonable to consider that chicken retina and pineal gland might serve as a useful tool for the development of drugs that could infuence clock function in man.

White-matter microstructure and language lateralization in left-handers: A whole-brain MRI analysis.

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.

Visuospatial impairment in Parkinson's disease: The role of laterality

Asymmetry is one of the unique and mysterious features of Parkinsons disease (PD). Motor symptoms develop unilaterally either on the left (LPD) or the right side (RPD). Incongruent data are available whether the side of onset has an impact on cognition in PD. The objective of this study is to compare the visuospatial performance of RPD and LPD patients. Seventy-one non-demented, non-depressive and right-handed patients were categorized into RBD (n = 36) and LPD (n = 35) groups. Rey-Osterrieth Complex Figure Test (ROCF) was evaluated by both the Taylors and Lorings scoring systems. Subsequently, we also performed subgroup analyses on patients having short disease duration (≤5 years, 15 RBD and 15 LPD patients). The standard analysis of ROCF (Taylors system) did not reveal any differences; however, the utilization of the Lorings system demonstrated that LPD patients had significantly worse visuospatial performance than the RPD subjects (3.0 vs. 2.0 points, median, p = 0.002). Correlation between the number of spatial errors and the degree of asymmetry was significant (r = −0.437, p = 0.001). However, this difference could not be observed in PD patients with short disease duration. LPD patients had worse visuospatial performance than the RPD subjects and the number of errors tightly correlated with the degree of asymmetry and long disease duration.

Ictal vocalizations occur more often in temporal lobe epilepsy with dominant (left-sided) epileptogenic zone

Objective:  To investigate the lateralization value of ictal vocalizations in temporal lobe epilepsy (TLE).

Right–left discrimination is related to the right hemisphere

We aimed to determine the functional localisation of right–left discrimination (RLD) by functional MRI (fMRI). In this study, 16 male volunteers were examined. There were three task sessions: one active and two baseline tasks. During the baseline tasks participants were instructed to show numbers with their fingers. The first baseline task was performed with the right hand, the second one with the left hand. During the active (RLD) task participants were also instructed to show numbers. The difference between baseline and active tasks was that during the active task the hand with which the participant should perform the instruction was assigned randomly. Thus, participants were unaware which hand should be used before the instruction command. During RLD, activations occurred in the right-sided frontal, precuneus, postcentral, angular, lingual, and superior temporal gyri. Activations also appeared in the left-sided temporal gyri and precuneus. Of the activations, 76.7% appeared in the right hemisphere, 23.3% in the left hemisphere. Conclusively, we found that RLD is mainly related to the right hemisphere, and requires activation of the parieto-temporo-occipital junction and the visual system including cuneus, precuneus, and gyrus lingualis.

Comparison of accuracy between FSL’s FIRST and Freesurfer for caudate nucleus and putamen segmentation

Although several methods have been developed to automatically delineate subcortical gray matter structures from MR images, the accuracy of these algorithms has not been comprehensively examined. Most of earlier studies focused primarily on the hippocampus. Here, we assessed the accuracy of two widely used non-commercial programs (FSL-FIRST and Freesurfer) for segmenting the caudate and putamen. T1-weighted 1 mm3 isotropic resolution MR images were acquired for thirty healthy subjects (15 females). Caudate nucleus and putamen were segmented manually by two independent observers and automatically by FIRST and Freesurfer (v4.5 and v5.3). Utilizing manual labels as reference standard the following measures were studied: Dice coefficient (D), percentage volume difference (PVD), absolute volume difference as well as intraclass correlation coefficient (ICC) for consistency and absolute agreement. For putamen segmentation, FIRST achieved higher D, lower PVD and higher ICC for absolute agreement with manual tracing than either version of Freesurfer. Freesurfer overestimated the putamen, while FIRST was not statistically different from manual tracing. The ICC for consistency with manual tracing was similar between the two methods. For caudate segmentation, FIRST and Freesurfer performed more similarly. In conclusion, Freesurfer and FIRST are not equivalent when comparing to manual tracing. FIRST was superior for putaminal segmentation.

Lateralisation of non-metric rhythm.

There are contradictory results on lateralisation and localisation of rhythm processing. Our aim was to test whether there is a hemispheric dissociation of metric and non-metric rhythm processing. We created a non-metric rhythm stimulus without a sense of metre and we measured brain activities during passive rhythm perception. A total of 11 healthy, right-handed, native female Hungarian speakers aged 21.3 ± 1.1 were investigated by functional magnetic resonance imaging (fMRI) using a 3T MR scanner. The experimental acoustic stimulus consisted of comprehensive sentences transformed to Morse code, which represent a non-metric rhythm with irregular perceptual accent structure. Activations were found in the right hemisphere, in the posterior parts of the right-sided superior and middle temporal gyri and temporal pole as well as in the orbital part of the right inferior frontal gyrus. Additional activation appeared in the left-sided superior temporal region. Our study suggests that non-metric rhythm with irregular perceptual accents structure is confined to the right hemisphere. Furthermore, a right-lateralised fronto-temporal network extracts the continuously altering temporal structure of the non-metric rhythm.