No abstract available.
Aphasia/*etiology/*physiopathology ; Brain Injuries/*complications ; Cognition/*physiology ; Female ; Functional Laterality/*physiology ; Humans ; Male

No abstract available.
Aphasia/*etiology/*physiopathology ; Brain Injuries/*complications ; Cognition/*physiology ; Female ; Functional Laterality/*physiology ; Humans ; Male

OBJECTIVETo investigate the brain functional laterality in motor areas during motor execution systematically.

METHODSFunctional magnetic resonance imaging (fMRI) was employed combined with right hand sequential finger movement task to investigate brain activation pattern and laterality in 8 right-handed subjects. 3dDeconvolve program of AFNI was used to estimate the hemodynamic response function and to generate activation maps. Then the laterality index (LI) was calculated and tested statistically.

RESULTAll motor areas including the areas which were previously considered to be engage in movement preparation only were activated in movement execution. In the activation map, it appeared left lateralization in cerebra and right lateralization in cerebella. After further statistical test, it was found that in primary motor area (M1), supplementary motor area (SMA) and posterior parietal cortex (PPC), there were left lateralization. While in premotor cortex (PMC), cingulate gyrus and basal ganglia (BG), the lateralization tendency was not obvious. The activation in cerebella is characterized with right lateralization.

CONCLUSIONThough there are tiny differences among subjects, most of the motor areas appear lateralized activation. Past studies only observed laterality in several motor areas. It may be due to the difficulty of the task or the experimental design.

Adult ; Brain ; physiology ; Female ; Functional Laterality ; physiology ; Humans ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; Male ; Motor Cortex ; physiology

Mean Kolmogorov entropy within one second is introduced and is used to analyze and localize the cortical lateralization based on spontaneous EEG and nonlinear dynamics. The results of analysis indicate: The conclusion drawn form the use of this method is almost consistent with that from other methods, but this method is more sensitive to cortical lateralization; this method can identify the differences of cortical lateralization between different brain areas. To analyze and localize cortical lateralization, mean Kolmogorov entropy based on spontaneous EEG is a good method.
Cerebral Cortex ; physiology ; Cognition ; Electroencephalography ; methods ; Functional Laterality ; physiology ; Humans ; Mental Processes ; physiology ; Nonlinear Dynamics ; Rotation ; Signal Processing, Computer-Assisted

BACKGROUNDAsymmetry of bilateral cerebral function, i.e. laterality, is an important phenomenon in many brain actions: arithmetic calculation may be one of these phenomena. In this study, first, laterality of brain areas associated with arithmetic calculations was revealed by functional magnetic resonance imaging (fMRI). Second, the relationship among laterality, handedness, and types of arithmetic task was assessed. Third, we postulate possible reasons for laterality.

METHODSUsing a block-designed experiment, twenty-five right-handed and seven left-handed healthy volunteers carried out simple calculations, complex calculations and proximity judgments. T1WI and GRE-EPI fMRI were performed with a GE 1.5T whole body MRI scanner. Statistical parametric mapping (SPM99) was used to process data and localize functional areas. Numbers of activated voxels were recorded to calculate laterality index for evaluating the laterality of functional brain areas.

RESULTSFor both groups, the activation of functional areas in the frontal lobe showed a tendency towards the nonpredominant hand side, but the functional areas in the inferior parietal lobule had left laterality. During simple and complex calculations, the laterality indices of the prefrontal cortex and premotor area were higher in the right-handed group than that in the left-handed group, whereas the laterality of the inferior parietal lobule had no such significant difference. In both groups, when the difficulty of the task increased, the laterality of the prefrontal cortex, premotor area, and inferior parietal lobule decreased, but the laterality of posterior part of the inferior frontal gyrus increased.

CONCLUSIONSThe laterality of the functional brain areas associated with arithmetic calculations can be detected with fMRI. The laterality of the functional areas was related to handedness and task difficulty.

Brain ; physiology ; Female ; Functional Laterality ; Humans ; Magnetic Resonance Imaging ; Male ; Mathematics ; Parietal Lobe ; physiology ; Prefrontal Cortex ; physiology

Attention ; physiology ; Female ; Functional Laterality ; physiology ; Humans ; Middle Aged ; Neuropsychological Tests ; Prosopagnosia ; complications ; Space Perception ; physiology ; Stroke ; complications

This study was done to evaluate differences in pressure pain threshold, grip strength, manual dexterity and touch pressure threshold in the dominant and non-dominant hands of right- and left-handed subjects, and to compare findings within and between these groups. Thirty-nine right-handed and twenty-one left-handed subjects participated in the study. Pressure pain threshold was assessed using a dolorimeter, grip strength was assessed with a hand-grip dynamometer, manual dexterity was evaluated using the VALPAR Component Work Sample-4 system, and touch pressure threshold was determined using Semmes Weinstein monofilaments. Results for the dominant and non-dominant hands were compared within and between the groups. In the right-handed subjects, the dominant hand was significantly faster with the VALPAR Component Work Sample-4, showed significantly greater grip strength, and had a significantly higher pressure pain threshold than the non-dominant hand. The corresponding results for the two hands were similar in the left-handed subjects. The study revealed asymmetrical manual performance in grip strength, manual dexterity and pressure pain threshold in right-handed subjects, but no such asymme-tries in left-handed subjects.
Adult ; Female ; Hand/innervation/*physiology ; Hand Strength/*physiology ; Humans ; Laterality/*physiology ; Male ; Motor Skills/*physiology ; Pain Threshold/*physiology ; Physical Stimulation ; Touch/*physiology

PURPOSE: The lateralization of cognitive functions in crossed aphasia in dextrals (CAD) has been explored and compared mainly with cases of aphasia with left hemisphere damage. However, comparing the neuropsychological aspects of CAD and aphasia after right brain damage in left-handers (ARL) could potentially provide more insights into the effect of a shift in the laterality of handedness or language on other cognitive organization. Thus, this case study compared two cases of CAD and one case of ARL. MATERIALS AND METHODS: The following neuropsychological measures were obtained from three aphasic patients with right brain damage (two cases of CAD and one case of ARL); language, oral and limb praxis, and nonverbal cognitive functions (visuospatial neglect and visuospatial construction). RESULTS: All three patients showed impaired visuoconstructional abilities, whereas each patient showed a different level of performances for oral and limb praxis, and visuospatial neglect. CONCLUSION: Based on the analysis of these three aphasic patients' performances, we highlighted the lateralization of language, handedness, oral and limb praxis, visuospatial neglect and visuospatial constructive ability in aphasic patients with right brain damage.
Aged ; Aphasia/*etiology/*physiopathology ; Brain Injuries/*complications ; Cognition/*physiology ; Female ; Functional Laterality/*physiology ; Humans ; Male ; Middle Aged

OBJECTIVETo explore effects of chewing-side preference (CSP) on cerebral cortical response during clenching task with functional magnetic resonance imaging (fMRI).

METHODSSeven patients with left CSP and 7 patients with right CSP were selected to perform the maximum voluntary clenching in intercuspal position, and block designed blood oxygenation level-dependent (BOLD) fMRI scan covering the whole brain was carried out.

RESULTSThere was activation in the parahippocampal gyrus in the four patients among seven with left CSP. But there was no activation in the parahippocampal gyrus among the patients with right CSP.

CONCLUSIONSThis research shows that the parahippocampal gyrus, which is associated with human memory and study, is activated during clenching task in the patients with left CSP.

Adult ; Bite Force ; Female ; Functional Laterality ; physiology ; Humans ; Magnetic Resonance Imaging ; Male ; Mastication ; physiology ; Memory ; physiology ; Parahippocampal Gyrus ; physiology ; Young Adult

INTRODUCTIONThe superficial and deep palmar arterial arches are the main sources of blood supply to all structures in the human hand, and variations in these arterial arches are quite common. Although several studies have reported diameters and variations of these arches, to the authors' knowledge, no study has correlated such changes to handedness in adults. It is likely that dominance may play a role in arterial variations, such as those seen in the diameter or number of arteries formed in the palmar arches, much like in other areas of the human body. This cadaver study was conducted to determine any such association.

METHODS42 formalin-fixed hands were dissected to expose the superficial and deep palmar arches. These arches were then thoroughly examined for any variations between the dominant and non-dominant hands. All cadavers were noted to be right-handed as per hospital records.

RESULTS19 complete superficial arterial arches (right hand 14; left hand 5) were found in the 42 hands dissected.

CONCLUSIONMost complete superficial palmar arches were found in the dominant hand of the cadavers studied, and therefore, handedness may have a role to play in determining palmar arterial arch variations in humans. Due to dominance or handedness, some arteries may likely persist into adulthood while others may become obliterated, thus leading to variations. Dissection of foetal hands may help to shed more light on the persistence or obliteration of various arteries after birth. Knowledge of such variations may prove helpful for surgeons during hand surgeries.

Cadaver ; Functional Laterality ; Hand ; anatomy & histology ; physiology ; Hand Deformities ; Humans ; Radial Artery ; anatomy & histology ; Ulnar Artery ; anatomy & histology