Attentional Modulation and Resource Allocation in Human Brain during Visual Stimulation with Stereogram - A fMRI Study

Objective: To explore regional brain activity changes during neural processing of human stereopsis by subtracting and reverse subtracting. Methods: Ten healthy volunteers participated in our fMRI experiments. Each subject performed two different vision-related tasks: plane figure and stereogram stimulations. After preprocessing, data were analyzed with SPM 99 software. We employed reverse subtracting method to obtain the group averaged deactivation maps. Results: There are two major findings in our study. The deactivated brain areas appear to be task dependence. Of plane figure stimuli, deactivation were mainly centered on default mode network, and with stereogram stimuli induced deactivation in regions of fusiform gyrus, thalamus and claustrum. Furthermore, task independent deactivation were observed in the medial frontal gyrus, superior temporal gyrus and insula. Conclusion: Our data further supported the notion that default mode network activity does exist during resting state. Nevertheless, stimulus is an important contribution to deactivation and should be considered when exploring the phenomenon of deactivation. Brain resources can be allocated automatically and continuously according to different task performance.