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

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

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

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

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

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

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

The brain modulates the immune system in an asymmetrical way, as shown by the association between paw preference and immune response in the mice. The purpose of the present work was to study the relationship between plasma tumor necrosis factor-alpha (TNF-alpha), nitric oxide (NO) and nitric oxide synthase (NOS) and brain lateralization. In the study, paw preference test was used to select right-pawed, left-pawed and ambidextrous mice. Mice were classified as the right-pawed if the right paw entry (RPE) score was equal to or greater than 30 (30-50), as the left-pawed if the score was equal to or less than 20 (0-20), and as the ambidextrous if the score was between 21 and 29. One week after the paw preference testing, the animals were injected intraperitoneally with either sterilized 0.9% saline or lipopolysaccharide (LPS) (5 microg/0.5 ml NS) and were killed 2 h later. Plasma was collected from each mouse. The level of plasma TNF-alpha was measured with ELISA kits provided by ENDOGEN. NO and NOS levels of plasma were detected with kits from Juli Biotechnology Company. The results showed that (1) in the normal mice, ambidextrous mice had higher NO levels compared with left-pawed mice (P<0.05). After the injection of LPS, plasma level of TNF-alpha was lower in left-pawed mice compared with those of the right-pawed and ambidextrous mice; plasma level of NO was higher in ambidextrous mice compared with those of the right- (P<0.01) and left-pawed (P<0.05) ones, and there was no significant difference in the plasma levels of NOS among ambidextrous, right- and left-pawed mice. (2) Immune parameters were correlated with the RPE scores. The shape of the curve describing this relation was similar to a parabola. In general, the levels of TNF-alpha, NO, NOS rose along with the increase of RPE if the scores were in the score range of left-pawed mice.After that, they reached a peak if the scores were in the score range of ambidextrous mice. Then they declined along with the increase of RPE if the scores were in the score range of right-pawed mice. In conclusion, plasma levels of TNF-alpha, NO and NOS were associated with brain lateralization, suggesting that the activities of Mo/Mphi were influenced by brain lateralization, and that the immune parameters were correlated with the RPE scores.
Animals ; Brain ; physiology ; Female ; Functional Laterality ; physiology ; Macrophages ; immunology ; Mice ; Mice, Inbred BALB C ; Nitric Oxide ; blood ; Nitric Oxide Synthase ; blood ; Tumor Necrosis Factor-alpha ; blood