Research


Here are my research topics:


Texture processing

''Simultaneous contrast'' is the phenomenon that our perception of a visual attribute is altered by a surround with a different level of that dimension. We use it to investigate the processing of texture density and regularity, i.e. ''simultaneous density contrast (SDC, top row in the right)'' and ''simultaneous regularity contrast (SRC, bottom row in the right)''. We found a bidirectional SDC effect: a denser surround reduces perceived density of the center, and a sparser surround enhances it. The data from texture density aftereffect again support this bidirectionality. Our results suggest the presence of density-selective channels in the visual system, with lateral inhibitory interactions between them. Moreover, we found that texture density processing is sensitive to binocularity that SDC declined as the difference in depth between center and surround increased. Our results challenge the previous view of a solely 2D representation of texture density.


See the papers:

  1. Sun, H.-C., David St-Amand, Baker C. L., & Kingdom, F. A. A. (2021). Visual perception of texture regularity: conjoint measurements and a wavelet response-distribution model. PLOS Computational Biology, 17(10): 1-28. [Link]

  2. Sun, H.-C., Kingdom, F. A. A., & Baker C. L. (2019). Perceived regularity of a texture is influenced by the regularity of a surrounding texture. Scientific Reports, 9(1637), 1-11. [Link]

  3. Sun, H.-C., Baker C L, & Kingdom, F A A (2018). Simultaneous density contrast and binocular integration. J. Vision, 18(6):3, 1–12. [Link]

  4. Sun, H.-C., Kingdom, F. A. A., & Baker C. L. (2017). Texture density adaptation can be bidirectional. J. Vision, 17(8):9, 1-10. [Link]

  5. Sun, H.-C., Baker C L, & Kingdom, F A A (2016). Simultaneous density contrast is bidirectional. J. Vision, 16(14):4, 1-11. [Link]


Material perception

How do we perceive object materials? Using human fMRI, we found that both ventral and dorsal visual areas involved in material perception. More specifically, the posterior fusiform sulcus (pFs) and V3B/KO are selective to glossy objects. In addition to known ventral areas involved in material processing, we found that higher dorsal areas play a role in processing binocular gloss information, and V3B/KO integrates monocular and binocular gloss cues. Interestingly, different fMRI response patterns are evoked in the secondary somatosensory area (S2) when viewing glossy and rough surfaces, suggesting a visual–somatosensory crossmodal network for material processing.

See the papers:

  1. Sun, H.-C., Welchman, A. E., Chang, D. H. F & Di Luca, M. (2016). Look but don’t touch: visual cues to surface structure drive somatosensory cortex. NeuroImage, 128, 353-361. [Link]

  2. Sun, H.-C., Di Luca, M., Ban, H., Muryy, A., Fleming, R. W. & Welchman, A. E. (2016). Differential processing of binocular and monocular gloss cues in human visual cortex. Journal of Neurophysiology, 115, 2779-2790. [Link]

  3. Sun, H.-C., Ban, H., Di Luca, M. & Welchman, A. E. (2015). fMRI evidence for areas that process surface gloss in the human visual cortex.. Vision Research, 109, 149-157. [Link]

  4. Sun, H.-C. (2015). The neural basis of visual material properties in the human brain. PhD dissertation. [Link]


Attention & bistable motion perception

Can attention affect bistable perception? Here we use the diamond stimulus to test this, which contains four occluders and four moving lines that can be perceived as coherent motion or separate motion. Participants were required to distribute their spatial attention on the occluders or the moving lines. We found that coherent motion was perceived more when attention was on the occluders, and this effect of attention was weaken when binocular or monocular depth cues were presented to define the depth of the occluders and moving lines. Our results suggest the idea that spatial attention alone can bias multistable perception by making attended areas look nearer.

See the papers:

  1. Sun, H.-C. (2010). The effect of spatial attention on multistable motion perception via the depth mechanism. Master thesis. [Link]

  2. Sun, H.-C. & Huang, S.-L. (2010). The Effect of Attention on the Multistable Motion Perception: Does It Involve the Perceived Depth? Paper presented at the 10th VSS Annual Meeting , Florida, USA [Link]