The neural organization in parietal cortex serving communication related to representation and cognition of facial expression.

猴子的顶叶内皮层与运动和感觉信息（如视觉、听觉和体感）的整合有关，并且已知是控制口腔和面部运动的区域。因此，对于口腔和面部运动，我们认为顶叶内皮层提供了与不同个体之间的意义交流相关的信息处理。如果我们记录下对自己的特定面部表情和观察他人的特定面部表情做出反应的脑壳内皮层的神经元，就有可能解释猴子的顶叶内皮层在与面部表情相关的意义交流中起着重要作用。在本研究中，我们运用行为学和电生理学技术来研究我们的意义交流理论。在行为实验中，通过图像分析仪器测量猴子的面部运动和眼球运动。首先，我们在猴子的脸上确定特征点（例如，嘴和眼球的角度）。其次，测量这些特征点的运动并进行数字化处理。因此，将猴子的面部表情分为三类，即威胁脸、惊吓脸和拍打脸。在电生理实验中，我们记录了清醒猴子的顶叶内皮层的神经元。为了确定这些神经元的反应特性，根据它们的行为模式分析这些神经元的活动。因此，我们记录了神经元对执行自己的特定动作和观察他人的类似动作做出反应。这些神经元在顶叶内皮层的存在说明顶叶内皮层与动作意义的编码有关。人们认为在顶叶内皮层也存在与面部表情交流相关的类似神经元。

The intraparieatal cortex of monkeys is related to an integration of motor and sensory information (e.g.,vision, audition and somatosensory), and is known to an area controlling the oral and facial movements. Accordingly, for the oral and facial movement, it is supposed that the intraparietal cortex subserves an information processing related to communication of meaning between different individuals. If we record neurons in the intrapaeital cortex which respond to both representing a specific facial expression of one's own and observing a specific facial expression of others, it is possible to interpret that the monkey's intraparietal cortex subserbes an important role on communication of meaning related to facial expression. In this study, we executed behavioral and electrophysiological techniques to investigate our theory on communication of meaning.In behavioral experiments, monkey's facial movement and eye movement are measured by an image-analyzing apparatus in the following steps. First, we decided characteristic points on monkey's face (e.g., angle of mouth and eyeball). Second, motions of these characteristic points are measured and are digitized. As a result, monkey's facial expression was classified into three categories, that is, menacing face, frightened face and smacking face.In electrophysiological experiments, we recorded neurons in the intraparietal cortex of awake monkeys. To identify response properties of these neurons, these neuronal activities were analyzed according to their behavior patterns. As a result, we recorded neurons which responded to both executing a specific action of one's own and observing the similar action of others. The existence of these neurons in the intraparietal cortex indicates that the intraparietal cortex is related to coding of action meaning. It is considered that similar neurons related to communication of facial expression also exist in the intraparietal cortex.