题  目：Understanding the Social Brain at the Single-Neuron Level
   主讲人：王硕 博士（美国普林斯顿大学）
   时  间：2017年3月23 日（星期四）下午3：00 - 4：30
   地  点：心理学院301会议厅
   

主讲人简介：
    王硕，美国普林斯顿大学博士后。本科毕业于新加坡国立大学计算神经学专业，博士毕业于加州理工学院计算与神经系统专业，师从Ralph Adolphs教授。现工作于普林斯顿大学，师从Alexander Todorov教授。运用多种认知神经学方法，包括心理物理学，眼动，脑电，核磁共振，人脑单细胞记录，以及自闭症人群和杏仁核损伤病人，在面孔处理（face processing）以及社会注意（social attention）领域有多项研究成果。在Neuron， Current Biology, PNAS，Nature Communications等国际重要期刊发表论文，是Journal of Neuroscience，Cerebral Cortex, Psychological Science等期刊的审稿人。

讲座摘要：
       My research studies the neural computation underlying social cognition. In this talk, I will first discuss face processing in the amygdala, which has long been implicated in encoding saliency and biologically relevant stimuli. I will show that single neurons in the human amygdala encode subjective judgment of emotions instead of physical stimulus properties. With a unique combination of single-neuron recordings, fMRI, and amygdala lesion patients, I will further show that the amygdala parametrically encodes both emotion intensity and ambiguity.

In the second half of the talk, I will also show some recent data that combine single-neuron recording with concurrent eye tracking in humans, where we find a top-down goal-directed signal in the human amygdala and hippocampus. The human medial temporal lobe (MTL) plays a key role in recognizing, categorizing, and learning about visual objects. Previous studies have found visual category selectivity in MTL neurons, but it remains unknown whether response selectivity could also be induced by explicit task demands, rather than by the visual properties of stimuli. We employed a goal-directed visual search task and recorded over 400 single neurons in the amygdalae and hippocampi from 10 neurosurgical patients with concurrent eye tracking. Here, we describe a set of “target neurons”, which differentiated fixations on search targets vs. distractors. This target response was predominantly determined by top-down attention and independent of bottom-up factors such as visual category selectivity or the format of search goals. In contrast, visual category selectivity was encoded in a separate class of neurons and was unaffected by our search task. Taken together, this shows that neurons in the human MTL not only encode object categories but also top-down goal signals with behavioral relevance.