Does hemispheric lateralization influence therapeutic effects of transcranial direct current stimulation?

This study investigated the effect of transcranial direct current stimulation（t DCS） polarity depending on lateralized function of task property in normal individuals performing visuomotor and simple repetitive tasks. Thirty healthy participants with no neurological disorders were recruited to participate in this study. Participants were randomly allocated into active or control condition. For the active condition, t DCS intensity was 2 m A with stimulation applied for 15 minutes to the right hemisphere（t DCS condition）. For the sham control, electrodes were placed in the same position, but the stimulator was turned off after 30 seconds（sham condition）. The tapping and tracking task tests were performed before and after for both conditions. Univariate analysis revealed significant difference only in the tracking task. For direct comparison of both tasks within each group, the tracking task had significantly higher Z score than the tapping task in the t DCS group（P 〈 0.05）. Thus, our study indicates that stimulation of the right hemisphere using t DCS can effectively improve visuomotor（tracking） task over simple repetitive（tapping） task.

Hemispheric Lateralization and Language Learning:Neurolinguisitc Considerations

This paper reviews research on hemispheric lateralization.There are neurological evidences for the lateralization of speech and language functions and inter-and intrahemispherical differences between males and females.The results for the study of lateralization and bilingualism are mixed,proving the complexity and multidimensionality of lateralization.

Differential Effect of Unilateral Amygdalar GABAA Receptor Agonist Injection on Low- and High-Anxiety Rats

The influence of γ-aminobutyric type-A (GABAA) receptors agonist (muscimol hydrobromide, 0.1 μg/0.5 μl) injections into the right or left basolateral amygdala (BLA) on the behavior of high-anxiety (HA) and low-anxiety (LA) rats subjected to the elevated plus-maze (EPM) test was investigated. Anxiolytic-like effects (increase of open-arm entries and open-arm time) was revealed only after administration of muscimol into the left (but not right) amygdala of HA animals. No effect was observed upon administration of muscimol to LA rats. These findings suggest an important role in anxiety regulation of the amygdalar GABA levels, and the assumed GABA hemispheric lateralization.

Dimensionality and Angular Disparity Influence Mental Rotation in Computer Gaming

Computer gaming is one of the most common activities that individuals are indulged in their usual activities concerning interactive systembased entertainment.Visuospatial processing is an essential aspect of mental rotation(MR)in playing computer-games.Previous studies have explored how objects’features affect theMRprocess;however,non-isomorphic 2Dand 3D objects lack a fair comparison.In addition,the effects of these features on brain activation during the MR in computer-games have been less investigated.This study investigates how dimensionality and angular disparity affect brain activation duringMRin computer-games.EEG(electroencephalogram)data were recorded from sixty healthy adults while playing an MR-based computer game.Isomorphic 2D and 3D visual objects with convex and reflex angular disparity were presented in the game.Cluster-based permutation tests were applied on EEG spectral power for frequency range 3.5–30 Hz to identify significant spatio-spectral changes.Also,the band-specific hemispheric lateralization was evaluated to investigate task-specific asymmetry.The results indicated higher alpha desynchronization in the left hemisphere during MR compared to baseline.The fronto-parietal areas showed neural activations during the game with convex angular disparities and 3D objects,for a frequency range of 7.8–14.2Hz and 7.8–10.5Hz,respectively.These areas also showed activations during the game with reflex angular disparities and 2D objects,but for narrower frequency bands,i.e.,8.0–10.0 Hz and 11.0–11.7 Hz,respectively.Left hemispheric dominance was observed for alpha and beta frequencies.However,the right parietal region was notably more dominant for convex angular disparity and 3D objects.Overall,the results showed higher neural activities elicited by convex angular disparities and 3D objects in the game compared to the reflex angles and 2Dobjects.The findings suggest future applications,such as cognitive modeling and controlled MR training using computer games.

Depth perception differences between hemispheres,genders,and eye dominance A study on evoked potential

BACKGROUND： Certain neural functions, such as peripheral reflexes, differ between genders, while higher brain functions, such as language, are asymmetrically distributed between the two hemispheres. The question remains as to whether depth perception differs between hemispheric laterality and genders, and whether it is affected by eye dominance. OBJECTIVE： To determine whether depth perception is influenced by factors such as gender, eye dominance, and hemispheric lateralization by recording evoked potential associated with depth perception. DESIGN, TIME AND SETTING： A contrast observation based on neuroelectrophysiology was performed at the Department of Biophysics of Ege University Medical School between June 2006 and April 2007. PARTICIPANTS： A total of 34 subjects, 19 females and 15 males, were included in the study with a mean age of （31.0 ± 6.9） years. All subjects were free of neurological or psychological disorders, or problems such as strabismus or vision correction. METHODS： Random-dot stereograms were used to elicit brain activity. A specially designed signal acquisition system employing two computers was used to record evoked potentials from both hemispheres via two pairs of scalp electrodes placed over the occipitotemporal areas of both hemispheres at symmetrical locations. MAIN OUTCOME MEASURES： Negative potential with a mean latency of （211.21 ±25.55） ms and a mean amplitude of （6.05 ± 1.53） pV was recorded from both occipitotemporal areas in 30 out of 34 participants. This was termed ＂Nd＂ and represented the evoked potential associated with depth perception. RESULTS： There were no significant differences in Nd amplitude or latency between the two hemispheres, the two eyes, or genders （P 〉 0.05）. CONCLUSION： The evoked potential associated with depth perception was not influenced by gender, hemisphere, or eye dominance.