题目：Characterizing the perceptual and attentional functions of the early visual system

报告人：Dr. Frank Tong ,Vanderbilt University

时间：2017年06月13日 星期二 13:00-15:00

地点： 王克桢楼1113

Much has been learned about the role of human V1 in perception and higher cognitive functions over the last decade. In comparison, the lateral geniculate nucleus (LGN) is commonly viewed as a relay station that simply serves to transfer information from retina to cortex. In this talk, I will describe our recent and ongoing fMRI work at characterizing the visual and attentional functions of the LGN and its relationship with early visual areas. We find novel evidence of orientation processing in the human LGN; moreover, attentional feedback can modify the strength of these orientation-selective responses (Ling, Pratte & Tong, Nat Neurosci, 2015). Although the LGN does not appear to be sensitive to long-range interactions between orientation stimuli, which can give rise to visual salience, our ongoing work suggests that both the LGN and V1 are sensitive to orientation-defined figures. These studies demonstrate that figure-ground processing involves distinct mechanisms of boundary enhancement and figure enhancement, and that both mechanisms operate in an automatic manner without requiring focal attention. Further experiments suggest that the sensitivity of the LGN to perceptual figures likely depends on automatic top-down feedback from the visual cortex. Taken together, our research suggests that the LGN has an integral role in more complex visual processes through its bidirectional connections with the visual cortex.

Host PI: Fang Fang