EEG Research On Spatial Processing Of Different Handedness

Handedness is considered to be an important factor affecting brain resource allocation in cognitive processing.Previous studies have disputed in how different handedness characteristics affect the allocation of brain resources during cognitive processing.Many researchers believe that the right brain function of left-handed or mixed-handed people is more developed than that of right-handed people,but the results of relevant empirical studies are contradictory and inconclusive.Previous studies have failed to unify the criteria for handedness,and choose different cognitive tasks.These problems may lead to conflict conclusions among different studies.Present study base on both international standards and China's national conditions,we selected mixed handedness(i.e.both left and right handedness can be used flexibly)and right handedness subjects,using EEG to investigate their differences in brain activation during spatial processing,with a wish to contribute to brain activation on handedness during cognitive processing.Spatial ability is a composite ability,which includes different sub-abilities,such as targeting;spatial orientation;spatial location memory;spatial visualization;disembedding;spatial perception.In this study,three of the most representative spatial sub-abilities were selected(disembedding;spatial orientation;spatial location memory),and the differences of brain function activation modes in these three spatial sub-abilities among different handedness were emphatically investigated.Since sex is an important factor in predicting spatial ability,so it is also included in the independent variable ranks in data analysis.In addition,because the intelligence can also predict spatial ability,so the present study collected intelligence scores(Raven&dot Advanced Progressive Matrices)as control variables.In experiment 1,EFT was used to examine the ability to separate a simple figure from a complex one;in experiment;in experiment 2,SPT was used to examine the ability to memorize the locations of an object in space;in experiment 3,MRT was used to examine the ability of the subjects to make mental choices about the three-dimensional spatial information.The main conclusions of this study are as follows:In Embedded Figure Test,behavior data showed that male mixed-handed subjects had a certain reaction time advantage over male right-handed subjects,and there was no difference between the two female handed subjects;On EEG data,the mixed-handed subjects showed bilateral brain activation pattern,while the right-handed subjects showed bilateral brain activation pattern in the frontal and temporal lobes,but in the core brain area closely related to spatial ability---parietal lobe,they showed left brain activation.The results showed that in the process of spatial information analysis,right-handed people showed dependence on left brain function(mainly left parietal lobe),while mixed-handed people showed the same dependence on bilateral brain.In Spatial Position Test,behavior data showed that male right-handed subjects performed significantly better than male mixed-handed subjects,and there was no difference between the two female handed subjects;On EEG data,mixed handedness subjects showed bilateral brain activation pattern,but in which female subjects showed right frontal lobe activation pattern;right handedness subjects also showed bilateral brain activation pattern,but in which female subjects showed left temporal lobe activation pattern.The results show that during static spatial information processing,the effect of handedness is more obvious in female groups.In the Mental Rotation Test,behavior data showed that mixed-handed subjects outperformed right-handed subjects in all;On EEG data,both handedness groups of male subjects showed bilateral brain activation mode;for female subjects,mixed handedness was bilateral brain activation mode,while right handedness was left brain dominant activation mode.The results show that the handedness effect is more obvious in the dynamic spatial information processing among female groups.Based on the above results,we can see that the spatial advantages of mixed-handed subjects are mainly reflected in the dynamic operation of spatial information,rather than in the static operation.The effect of handedness on spatial manipulation was regulated by sex,while female subjects obtained small effects.What's more,the brain activation patterns of mixed-handed and right-handed subjects were both regulated by types of spatial task and sex.Overall,these Chinese subjects showed bilateral activation patterns.Some subjects(mainly female subjects)showed dominant activation in the right frontal lobe or left temporal lobe in certain spatial tasks.The results of present study support the interaction among handedness,sex and task types,which together affect people's spatial manipulation and brain activation patterns.