title: Decoding brain responses to pixelized images in the primary visual cortex: implications for visual cortical prostheses.
abstract: Visual cortical prostheses have the potential to restore partial vision. Still limited by the low-resolution visual percepts provided by visual cortical prostheses, implant wearers can currently only "see" pixelized images, and how to obtain the specific brain responses to different pixelized images in the primary visual cortex (the implant area) is still unknown. We conducted a functional magnetic resonance imaging experiment on normal human participants to investigate the brain activation patterns in response to 18 different pixelized images. There were 100 voxels in the brain activation pattern that were selected from the primary visual cortex, and voxel size was 4 mm × 4 mm × 4 mm. Multi-voxel pattern analysis was used to test if these 18 different brain activation patterns were specific. We chose a Linear Support Vector Machine (LSVM) as the classifier in this study. The results showed that the classification accuracies of different brain activation patterns were significantly above chance level, which suggests that the classifier can successfully distinguish the brain activation patterns. Our results suggest that the specific brain activation patterns to different pixelized images can be obtained in the primary visual cortex using a 4 mm × 4 mm × 4 mm voxel size and a 100-voxel pattern.
authors.affiliation: Department of Biomedical Engineering, Chongqing University, Chongqing, China ; Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA.
authors.forename: Bing-Bing
authors.initials: BB
authors.lastname: Guo
authors.affiliation: Department of Biomedical Engineering, Chongqing University, Chongqing, China.
authors.forename: Xiao-Lin
authors.initials: XL
authors.lastname: Zheng
authors.affiliation: Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA.
authors.forename: Zhen-Gang
authors.initials: ZG
authors.lastname: Lu
authors.affiliation: Department of Biomedical Engineering, Chongqing University, Chongqing, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Lab of Visual Damage and Regeneration & Restoration, Third Military Medical University, Chongqing, China.
authors.forename: Zheng-Qin
authors.initials: ZQ
authors.lastname: Yin
authors.affiliation: Department of Biomedical Engineering, Chongqing University, Chongqing, China.
authors.forename: Wen-Sheng
authors.identifier: 0000-0002-2201-4177
authors.initials: WS
authors.lastname: Hou
authors.affiliation: Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Meng
keywords: brain activation pattern; electrical stimulation; functional magnetic resonance imaging; low resolution vision; nerve regeneration; neural regeneration; pixelized image; primary visual cortex; visual cortical prosthesis; voxel size