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学者论坛:Visual perceptual learning: A new perspective
文:人力资源部教师发展中心 来源:党委教师工作部、人力资源部(教师发展中心) 时间:2023-04-18 1593

  教师发展中心“学者论坛”活动特别邀请北京大学余聪教授来校作学术交流。具体安排如下,欢迎广大师生参加。

  一、主 题:Visual perceptual learning: A new perspective

  二、主讲人:北京大学 余聪 教授

  三、时 间:2023年4月20日(周四)9:30-11:00

  四、地 点:清水河校区综合楼309报告厅

  五、主持人:生命科学与技术学院 李永杰 教授

  六、主讲内容:

  Visual perceptual learning (PL) shows specificity to the trained retinal location and orientation, which is often taken as indications of neural plasticity in the early visual cortex. However, we created a “double training” paradigm to demonstrate complete learning transfer, suggesting that PL is mainly a high-level learning process beyond the visual areas.

  Why is PL specific in the first place? Double training results suggest that the specificity may be to do with the untrained conditions. We used a continuous flash suppression technique to create “bottom-up only” or “top-down only” exposure stimuli, and found that pure bottom-up exposure of an untrained location or orientation, or pure top-down influences, can both enable learning transfer. Therefore, learning specificities may result from functional disconnections between high-level learning and under-activated neurons representing untrained stimulus conditions.

  What is actually learned in PL? We studied orientation learning with luminance gratings and symmetric axes of dot patterns, and motion direction learning with first- and second-order motion stimuli. Each pair of stimuli were physically distinct, processed by different neural encoders, and with different precision (thresholds). Yet double training enabled complete mutual transfer of learning, indicating that concepts of visual features, such as orientation and motion direction are being learned.

  If time allows, I will present some two-photon imaging data on macaque visual areas and discuss this technology from the perspective of a psychophysicist.

  七、主讲人简介:

  余聪,北京大学心理与认知学院教授、博士生导师,国家级人才、国家自然科学基金委杰出青年基金获得者。1995年获University of Louisville实验心理学博士学位,1995年至2003年分别在University of Houston和University of California, Berkeley做博士后研究,2003年任中国科学院神经科学研究所研究员(百人计划),2006年任北京师范大学认知神经科学与学习国家重点实验室研究员,2012年起任北京大学心理系(现北京大学心理与认知科学学院)教授暨北京大学-清华大学联合生命科学中心高级研究员。担任第九届亚太视觉科学大会主席(2013)、Vision Research期刊编委(2006-)等。曾获教育部自然科学一等奖等奖项。目前承担有科技部重大研究计划(脑计划)课题等。主要研究方向包括:(1)运用心理物理学方法,结合脑成像和计算模型手段,研究人类视觉过程,尤其是知觉学习(感觉训练)过程的脑机制,以及知觉学习在临床视觉和工程中的应用;(2)运用清醒猕猴双光子钙成像技术,研究视觉过程的神经机制。

  八、主办单位:教师发展中心

    承办单位:生命科学与技术学院


编辑:林坤  / 审核:林坤  / 发布:陈伟

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