Visual attention modulates the asymmetric influence of each cerebral hemisphere on spatial perception.

Meijian Wang,Lingyan Xue,Xiuhai Wang,Yao Chen,Dan Huang

doi:10.1038/srep19190

Abstract

Although the allocation of brain functions across the two cerebral hemispheres has aroused public interest over the past century, asymmetric interhemispheric cooperation under attentional modulation has been scarcely investigated. An example of interhemispheric cooperation is visual spatial perception. During this process, visual information from each hemisphere is integrated because each half of the visual field predominantly projects to the contralateral visual cortex. Both egocentric and allocentric coordinates can be employed for visual spatial representation, but they activate different areas in primate cerebral hemispheres. Recent studies have determined that egocentric representation affects the reaction time of allocentric perception; furthermore, this influence is asymmetric between the two visual hemifields. The egocentric-allocentric incompatibility effect and its asymmetry between the two hemispheres can produce this phenomenon. Using an allocentric position judgment task, we found that this incompatibility effect was reduced, and its asymmetry was eliminated on an attentional task rather than a neutral task. Visual attention might activate cortical areas that process conflicting information, such as the anterior cingulate cortex, and balance the asymmetry between the two hemispheres. Attention may enhance and balance this interhemispheric cooperation because this imbalance may also be caused by the asymmetric cooperation of each hemisphere in spatial perception.

Highlights

The allocation of brain functions across the two cerebral hemispheres has aroused public interest over the past century, asymmetric interhemispheric cooperation under attentional modulation has been scarcely investigated
The difference in the compatibility difference index (CDI) and egocentric asymmetry index (EAI) between the neutral and attentional tasks represents the modulatory effect of attention on the CDI and EAI, respectively. Both attention and task difficulty influenced the reaction time (RT) on the allocentric position discrimination task (Fig. 2A,B and Supplementary Figure S1A,B)[30], but only attention modulated the characteristics of allocentric perception. This finding implies that the changes in RT caused by cue-attention and contrast-difficulty depend on different mechanisms related to allocentric location judgment; attention, but not a reduction of difficulty, can increase the processing of conflicting information
The different RTs between compatible and incompatible tasks may be due to the influence of egocentric representation on allocentric judgment[11] or to the influence of conflict information, and this effect was reduced by attentional modulation (Fig. 2)

Summary

Introduction

The allocation of brain functions across the two cerebral hemispheres has aroused public interest over the past century, asymmetric interhemispheric cooperation under attentional modulation has been scarcely investigated. An example of interhemispheric cooperation is visual spatial perception During this process, visual information from each hemisphere is integrated because each half of the visual field predominantly projects to the contralateral visual cortex. Visual information from each hemisphere is integrated because each half of the visual field predominantly projects to the contralateral visual cortex Both egocentric and allocentric coordinates can be employed for visual spatial representation, but they activate different areas in primate cerebral hemispheres. Functional imbalance between the left and right cortical areas involved in processing conflict, such as the ACC, may be responsible for the asymmetry in allocentric-egocentric incompatibility. This imbalance may be due to asymmetric interhemispheric cooperation

Methods

Results

Conclusion