The perception of visual information is composed of various components of vision, such as form, color, and movement. Previous animal study investigated the functional organization of visual processing and revealed the extrastriate-associated visual cortex for visual motion and color [1], [2], [3]. However, the functional organization of and networks for visual processing in humans remain unclear.

Electrical brain stimulation (EBS) has become the gold standard for localizing the eloquent cortex and provides important information for the preservation of brain functions during surgery. EBS brain mapping is critical for drawing a plan for the resection of involved brain tissue without causing major sensorimotor or cognitive impairment in patients, particularly those with epilepsy and brain tumors in eloquent areas. The information obtained by EBS is useful not only for surgical strategies, but also for elucidating human brain functions [4], [5]. A previous human EBS study revealed that form, color, and moving sensations were distributed in different areas of the visual cortex [6]. Visual symptoms were detected by a stimulation of not only the occipital lobe, but also the parietal and temporal lobes [7]. Diffusion tensor imaging (DTI) is a newly developed imaging technique for calculating the anisotropic diffusion of water molecules, and has enabled visualization of in vivo white matter pathways in the living human brain. The combination of EBS and DTI has provided novel information on human brain networks associated with the basal temporal language area, posterior superior temporal auditory cortex, negative motor area, and frontal eye field [8], [9], [10], [11].

Therefore, the present study investigated the networks associated with visual functions using EBS and DTI.